Here's an alphabetically arranged list of Isetta restoration topics that apply to the US Export Sliding Window Coupe. Not all information listed here carries over to the earlier bubble window models.
This section of Isetta Tech will be updated on a semi-regular basis. Please use the Feedback link to let us know what issues you would like to see addressed, correct us on any bogus info we've dished out or suggest other/better ways to get those Isettas back on the road where they belong.
Revised September 2005
Click on a letter that corresponds to a topic that begins with that letter.
AIR CLEANER CANISTER
Your canister is basically an elongated coffee can that bolts to the rear fender (mud/splash guard) bracket and runs from side-to-side. It has a rear inlet tube welded on at a right angle that connects to the external air intake via angled rubber hose, an early Ram-Air design if you will. The canister connects to the carburetor via a J-shaped hose on the engine side. This J-shaped hose clamps onto the canister cover containing the air filter.
If you don't do anything else in the way of maintanence on your Isetta, make sure you change the oil and at least clean, if not replace, the air filter on a routine basis.
Many different types of batteries have been sucessfully used in Isettas. The Isetta electrical system calls for 12 volt, 31 amp battery with negative ground. We have a Harley-Davidson Non-spillable (sealed) battery in our car. It's H-D part number 65989-97. This battery measures 7" wide by 6" tall by 3 1/2" deep and retails for about $75.00. With it's compact size, there's no worry about fitting in the battery box or being too tall to fit under the seat. Life expectancy is in the 3 year range. Westco Battery offers a broad range of batteries and related products that are perfect for many micro/mini cars. You can search on motorcycle batteries and plug in BMW to see their offerings or give them a call to see what they suggest.
Other battery options that have been used include Sear's (and other brands) riding lawn mower / ATV batteries. Some models are slightly less money than other choices but may not last as long. You will probably find that most of these types of batteries have the removeable caps to add distilled water to the cells, one more maintenance issue to deal with. Most we've seen also require that the electrolyte be added to the battery once you purchase it so it may not be ready to use off-the-shelf. One item that we didn't care for on these units was the ventilation tube. This tube runs down one side of the battery and it's name is self-explanatory. There's just something about having battery acid fumes vented under the seat of the car that isn't appealing. One could always drill a hole in the battery box and vent it outside but punching a hole in the car wasn't an option.
You might consider picking up a good battery charger at the same time. Westco sells a fully automatic charger, the AccuMate Power Charging System. It's their model number LS6/1.2 and sells for $60.00. It's a small, switchable, fully automatic charger for 6V / 12V small batteries. This unit won't allow you to accidentally reverse polarity and comes with a neat pigtail adapter that you can attach to the battery and leave under the seat. When need be, just plug the pigtail into the charger and plug the charger into the wall. When the green LED comes on, you're done. An LED will also indicate that the battery is no longer chargeable and should be replaced. It will also sit there for months and maintain a full charge without burning your car, garage and/or house to the ground. They also include the old standby alligator clips too if you move it around from one vehicle to another.
One word of wisdom on selecting a battery is to make sure that you don't get one that's too tall. That includes selecting one that has it's posts either recessed or side mounted so there's no danger of having the bottom of the seat springs come into contact with the posts and causing a potentially disastrous short. Assuming that you intend to use the factory grounding stud in front of your battery box, you may also find that having the negative post to the right (passenger) side allows a neater battery cable installation too. Finally, you might want to put some sort of mat under your battery. The acid-free mats seem impossible to find any more in our area. We went to the hardware store and bought a square foot of 1/16" neoprene rubber sheet and cut a mat to fit our box. Some owners, this one for instance, also cut a square of the same neoprene punched several holes around the outer perimeter and tie-wrapped it to the bottom of the seat springs directly above the battery just to be safe. More than one Isetta has burned to the ground or has been severely damaged due to those seat springs shorting across the battery posts. Electric chairs have their place but your Isetta is not one of them.
Public Enemy #1 when it comes to rotting and rusting out. New battery boxes are easy to come by through parts suppliers. The target price should be around $50.00. Being a fairly simple item, a sheet metal shop should be able to make one up for you as well.
If your floorboard has rotted away around the box, you'll need to replace that sheet metal so your new box fits the same rectangular cutout in the floorboard rather than install a larger box. Why? First, if you should go to a larger (deeper front-to-back) box, you'll be chewing up the real estate where your voltage regulator is mounted behind the battery box. If that happens, there won't be sufficient room between the back of the box and the underseat heater for the regulator to fit. You'll have to improvise and mount it off-center to the passenger side of the floorboard or the inside of the spare tire well. This will work OK ... just stand advised before you get started. Second, there is a lateral steel brace welded to the underneath side of the floorboard behind the box. You would have to remove this brace and relocate it.
One nice touch to add to that new box is a mat, preferrably of the acid resistant variety. These mats seem to be disappearing from the auto parts stores' inventory these days though. We bought a 1' piece of neoprene rubber stock from the hardware store and cut one from that. Works like a charm for a buck and a half.
Another area where we've seen lack of attention is the battery tie-down strap. The original factory boxes had a small wing on either side where a threaded, L-shaped rod was attached, threads pointing up. Once the battery is installed, a flat bracket is placed on top of the battery. The threaded part of those vertical rods goes through each end of the bracket and are secured by wing nuts on either side. That battery isn't going anywhere. Many people have stuffed foam rubber and/or pieces of wood around their batteries to keep it in place. Some have rigged up a bungee cord or two to do the job as well. That may be better than nothing but the factory setup is the way to go.
Note: If you have a Brighton-built, British Isetta, your car has Girling brake components installed. Please disregard this section as it doesn't apply to your car!
The Isetta utilizes a simple design that's easy to work on. On US Export models, the front brakes use ATE wheel cylinders with a 17mm bore. The two cast aluminum brake shoes rely on riveted lining for stopping power and there are two identical springs, one top and one bottom, that tie the two together. Two adjustments can be made here. The angle of the shoe/linings can be adjusted for parallel contact with the inside of the drum via small screw on each shoe. With only 50 square inches of braking surface, you want these shoes perfectly parallel to the drum. The conical brake adjuster at the bottom of the assembly is used to regulate the distance between the shoe/lining and the drum.
While BMW's Isetta sales brochure specifically states "four wheel brakes", the rear has only one brake mounted on the right rear. That's three total.Given that it stops a live axle that both rear tires are mounted to, the claim is accurate but seems somewhat misleading. The rear brake is similar to the front units but uses a cylinder with a smaller, 12mm bore. In addition, there are two studs, one on the top of each shoe, that the actuating levers for the hand brake cable fasten too. The spring that fastens the shoes together at the top differs from the other five brake springs in that the eyelets are rounded to clip into a machined slot in each of the studs and secure those levers.
The master cylinder, also an ATE unit, is bolted to the middle frame crossmember and is actuated by an adjustable rod that connects to the brake pedal. The brake lines have 10mm x 1mm threads and fasten into 18" brake hoses at all three ends. The system calls for DOT Type 3/4 fluid. ATE offers their own branded fluid but any reputable brand will do the job for you.
Master and Wheel Cylinders
One of the most common problems with Isettas that have been setting up is the demise of the braking system. Brake fluid takes on moisture over time and that moisture is what ruins the pistons in your master and brake cylinders. Old cylinders can leak and/or be sluggish. Many simply freeze up. You have several choices of what you can do to get your brake system back to looking like this:
Do the work yourself, or
Send them off to a rebuilding facility , or
Buy new wheel cylinders from Isetta parts suppliers
Let's say you're on a budget or just like to do the work yourself. Parts suppliers can get you the rebuild kits needed for the wheel and master cylinders. The two front wheel cylinders are identical and use a 17mm bore. The single rear cylinder uses a smaller 12mm bore. In a nutshell, the cylinders need to be removed, dismantled, thoroughly cleaned and lightly honed to remove any pitting that may have occured from moisture. Be careful when removing stubborn pistons. These things are made out of pot metal and the little rectangular protrusion on the outside end can snap off it you try to twist it too hard. Use a heat gun and lubricant on these parts and then give it another try. Be sure to take those bleeder valves out and be careful with them as well. Use some PB Blaster and a heat gun to loosen the threads up first. Having to hog out broken valve threads is a pain and one you can avoid if you're patient.
White Post Restorations is a well-respected organization that provides all type of resto services including brake and master cylinder rebuilds. They can also brass-sleeve your cylinders to eliminate that corrosion and pitting too. Check out their Web site or give them a call at (540) 837-1140 for a quote on having those brake cylinders done by professionals. Another company that can help is Sierra Specialty Automotive. They can be reached by phone at (800) 4-BRASS-1 or (800) 427-2771.
You may find that the quote for a truly shot set of cylinders isn't that far off from just buying a fresh new set. Suppliers carry the original ATE units that bolt right onto your car. As of March 2005, wheel cylinders are running in the $90.00 each range, $190.00 for a master cylinder assuming you're sending yours back as an exchange, or core, unit. For what it's worth, we know of at least two former Isetta owners who simply installed early VW Beetle wheel cylinders in their cars at a fraction of the cost. If you want a second opinion, take those Isetta cylinders to your local Euro auto parts store and compare them to the early VW Beetle/Ghia/Bus units. The ones we've seen look virtually identical but have the bleeder valve at the bottom so proceed with caution on this one. Upside down, no worky. You can also visit California Imports' Web page and take a sneak peak at 'em. You're looking for a 1952-1957 Beetle / Ghia wheel cylinder part number VWC-113-611-053 (rear) and VWC-113-611-055 (front). They run around $40.00 each, substantially less than other sources charge. Better than that, why not just go to your local VW repair shop. If they're working on vintage models, and you can bet they are, they'll have these on the shelf. That may be the quickest, safest and possibly cheapest bet of 'em all. Whatever you do, get the right ones. Your brake system is no place to be taking shortcuts and pinching pennies!
Make note that we have not used the VW wheel cylinders and do not have first hand experience with them! If anyone out there can chime in on this topic, please follow up with us so we can get the word out on this potential option.
One other note that's worth slipping in here. There has been a debate over using front wheel cylinders on the rear. At a couple of points in time, new rear cylinders were impossible to come by so some folks just popped a front unit on their rear brakes. The fronts and rears use identical bolt patterns and physically fit either way. The debate centered around the issue of the rear brake locking up with the larger, 17mm cylinder. One side said it was dangerous, the other shrugged it off. It's been noted that the front brakes on an Isetta do approximately 80% of the stopping with 20% of the task going to the rear unit, not unlike scores of other more conventional cars. We're not about to jump into the middle of that one but wanted to make you aware that it's caused more than one tongue-wrestling match. One fine-tuning tip that's been passed along is to have the rear brake shoes engage just slightly before the front shoes to give yourself a bit of a stopping advantage. Remember, on a good day, you only have 50 square inches of brake lining working for you.
Lines and Hoses
Moving right along to the brake lines and hoses, you may find deteriorated rubber hoses and crimped brake lines. New brake line kits are available at under $50.00, come cut to the correct length and are made from a semi-stainless steel material referred to as "cunifer". If you're gonna hit the parts store and buy 'em off the shelf, the line lengths are as follows: rear=44", right front=40" and left front=20". 18" brake hoses with 10mm x 1mm metric male/female fittings work fine and allow for flexibility and movement of both steering and chain drive. If you want to trick your car out a bit, why not get a set of 3 braided stainless steel hoses from Bavarian Autosport? It's their part number SSBH-18MF. This item is not currently listed on their Web site but you can always call them at (800) 535-2002 to check availability. Another option is to visit California Imports and check out their part number C12-5585-12. That's a 19" stainless steel brake hose for early Beetle, Ghia and Bus.
One word of warning about off-the-shelf brake lines. While the lines themselves are functionally OK, you'll find that the threaded ends that attach to the hoses are about half again longer than the factory threads. What will happen is the the female hose threads only go down so far on the longer threads of the lines. So what? Well, when you put your two front L-brackets and retainer springs in the middle, the line/hose won't compress, or even reach, that U-spring. Even worse, the hose won't be able to pull the line threads as far as they need to go for a tight fit. Your line/hose will just rattle around in there. Take your hose, L-bracket and spring to the parts store if you're considering this. You'll see what we mean. Perhaps there are shorter threaded brake lines or longer retainer springs. We had no luck finding them in the parts stores in Austin.
Replacement of those lines can either be a snap or a real pain depending on the disposition of your car. The 'snap' part? That's if you're body is off of the frame. You'll need to make multiple bends and test fitting is a must to have it come out right. The 'real pain' part? It's a difficult procedure if you're working under the car but it can be done. The two most critical bends you'll have to make are for the lines exiting the master cylinder on top. They come up at an angle and must be bent back down so they clear the bottom of the floorpan on both sides. In addition, the right line must come forward, around and in front of the battery box. Both lines must then come through the middle frame crossmember, under the frame and then forward to the outside where they will attach via L-bracket to the lower outside of your wheel wells. That L-bracket and associated spring also holds the line and hose tightly together.
Finally, be sure and use the correct brake fluid. ATE makes their own brand of DOT 3/4 fluid although any quality brand should do a fine job for you.
Adjusting the brakes on your Isetta is a pretty straightforward process. There are two points that will require your attention. We recommend adjusting the shoes for perfectly parallel contact with the inside of the drum first. This is accomplished by turning the small, slotted screw located in the approximate middle of each brake shoe either in or out until the surface of the lining and drum are flush. Turning this screw clockwise will move the outer edge of the shoe in an outward arc, vice versa for counter-clockwise. An easy way to check your work is to get a piece of chalk and mark a stripe across each lining at the top, middle and bottom. Make your first adjustment, put the drum and tire back on the car and give it a spin while someone steps on the brake pedal. Remove the tire and wheel and look to see where the chalk is wiped off the lining. If you see chalk left on the inside of the lining, you know that the shoe is cocked to the inside too much. Just give your adjusting screw a turn or two in the clockwise direction and repeat the process, making sure to put new chalk marks over your old ones. Once you have a "clean sweep", tighten the locking nut down on the adjusting screw and move on to the next shoe. If this is a first pass, remember that those linings may not be a perfect 360. The thing that really did it for our car was cruising down the street at 30-35 MPH and literally slamming on the brakes. Multiple times. You'll be surprised at how fast those new shoes get acclamated to their new environment!
The other adjustment moves the linings either closer to or away from the drum surface and is accomplished with the brake adjusting screw at the outside bottom of each brake backing plate. Turning this "coneheaded" screw in (or clockwise) will push the shoes outwards toward the inner drum surface. Counter-clockwise will back it away from the drum. You'll probably want it as close as you can get it to the drum for quick action. Spin your tire and turn that adjusting screw clockwise until the tire comes to a stop. Now back the screw off while giving the tire another spin. At the point you no longer have any resistance, audible or otherwise, take a wrench and tighten the locking nut down while holding the square head steady with a crescent wrench. Do this two more times and your finished (for now). You'll want to check this adjustment periodically as the new linings adapt to their environment as well as compensate for normal wear.
"Hey, that's cool but when I back the lower adjusting screw out, the tire turns OK but there's a lingering scraping/brushing sound once per revolution. What's wrong?" Your brake is telling you that the shoe(s) need a bit more attention in regards to being perfectly parallel to the drum surface. Go back and try the chalk routine. You'll probably find that this will take a bit of tweaking to get it perfect but it's pretty quick work when all is said and done. This sound could also be atttributed to a lining that has a slight high spot in it. "Easy for you to say! I've tried everything and it still has a subtle brushing sound I can't get rid of". That could be a couple of things. One, did you have your drums turned when you had the new linings installed? If not, you're probably fighting a lost cause. Have those drums turned. "Of course I had them turned! What's your number-two bright idea?" Maybe you didn't have the linings arc'ed. If those linings aren't riveted in starting from one end working to the other, they can pooch up, very slightly, towards the middle. Nothing is perfect either. That's the reason to lay out a few extra bux to have them trued up and factor that out of the equation. You're gonna have to do better than that." Did you have that wheel and tire tightened down good and snug or did you just have it on finger tight? If just finger tight, it may be rotating in an uneven pattern and causing some very slight wobble between the lining and drum."Been there, done that". Drive your car. Take it to a low/no traffic area. Use your brakes frequently over short hauls and vary the speeds you are stopping from. Let those new linings get used to having to do some work instead of sitting in a cardboard box on your shelf. Beats the heck out of yard work!
You'll probably find that the combination of all-of-the-above will do the trick. Even with all of the adjusting we did, that slight rubbing sound was still there. One owner asked, "Have you come crusing down the street and just flat-out slammed on the brakes in front of your house a few times?". No, we hadn't. But we did. Somewhere between that excercise and just putting a lot of short haul starting and stopping, the brakes became obviously better over a fairly short period of time. Just be sure to go back and check your adjustments occasionally, especially in the first 500-1000 miles you put on your car.
BRAKES, HANDBRAKE INSTALLATION AND ADJUSTMENT
This is an installation that has to be done in the correct order to be successful. First, you'll want to attach the cable to the rear brake. After you pass your cable through the slot at the bottom of the backing plate, be sure and crimp that small arm the cable passes through so it doesn't pull out on you. Remember, you may be in a panic or be parked on an incline when you need this brake so make sure it's good and tight back there.
Next, route it across the top of the right rear spring, over the rear of the frame and through the hole in the firewall in the spare tire area. Make sure you have a new rubber grommet in that hole to eliminate chafing and wear on the outer part of the cable. Run the cable forward to the outside of the left wheel well.
Next, make sure that your rear brake drum is off of the car. This will allow the rear shoes to expand outward as you pull the cable up front. Failure to remove the drum will make this task literally impossible. Now comes the tug-of-war part. Many Isetta restorers have trimmed around 1/4" of the cable's outer cover back from the threaded piece that fits into the handbrake mounting plate to allow for a bit more leverage since it will expose that much more of the actual cable inside. We didn't have to do that. Just take a pair of vice grip pliers and clamp it down good and tight on the very front of the cable. Now, get your mounting plate and lay it on the floor. Pull that cable out as hard as you can until you have enough to drop through the slot on the side of the threaded collar the cable fits into. Let go and take a break.
Next, place that small, round slotted steel piece on the end of the cable until the cable end fits into it snuggly. You'll need to grab your brake handle and spread the two tangs at the bottom (the ones with the round holes where that steel piece fits) apart. Now you can place that steel piece, cable end inserted, into place and crimp down around it so the steel piece has no where to go. Install your mounting plate/cable assembly to the wheel well, position the hand brake lever on its pivot, replace the steel retainer plate and cover and you're done. You'll be amazed, after all of that pulling, how easy it operates once it's installed.
To adjust your hand brake, put your rear brake drum back on the car along with the right rear tire. You're looking to have that tire stop from rotating at 3-4 clicks of the handle. That's where the threaded adjustment collar comes into play. Back it out a few turns at a time, if need be, and have an assistant spin the rear tires. It shouldn't take much adjusting, especially if you've had your brakes relined. Check from time to time to account for wear of the rear linings.
What if I've backed the inside threaded collar out and it still doesn't stop on click 3 or 4? That probably means that your rear brakes haven't been adjusted yet. The culprit will most likely be the brake adjuster at the bottom and you'll probably find that it is turned too far out, leaving a greater distance between the shoe and drum than is desirable. Just loosen the nut that secures it and turn it clockwise until you hear the shoe dragging on the drum (or the rear tire quits turning). Now, back it off counterclockwise until the tire rotates smoothly with no audible sound. Try your hand brake again and see if that didn't do the trick.
Finally, there are two methods of applying your brake. One is to grab it and rachet it back to the stop position. The other is to push the release button in and do the same thing, the silent treatment. The latter is the preferred method. Why? If you use the rachet method enough times, you will eventually wear the chisel point off the top of the spring-loaded actuating rod inside the brake handle. When that point is gone, there is nothing left to engage your hand brake and keep it there.
As we have mentioned, the braking system in a neglected Isetta may well be one of the worst parts of the car. While the master and wheel cylinders are probably at the top of everyone's list, the brake linings have to be dealt with too. This is no place to cut a corner and brake linings being relatively inexpensive, go for six new ones.
On higher mileage cars (ours had 34,050 on the odometer) you can bet that the brakes have had at least one new set of linings since it left Munich. In order to remove the old lining, the rivets must be drilled out in order to make way for new ones. If this is the case, it's almost a sure bet that at least some of the original rivet holes in the shoes have been enlarged by this drilling process. You may find that the new rivets available from suppliers are both too small in diameter and/or not long enough to properly cinch down on the inside of the shoe and hold the new lining in place. Here's something you can do that's cheap and works.
Take your shoes (hopefully you've cleaned them up and media blasted them ahead of time) to the brake shop, have them pull out their rivet selection and determine which size is best suited for your linings and shoes ... the larger in diameter the better. Now, check to see if the rivet will be able flare out enough on the inside of the shoe to hold the new lining. If not, make a run to the hardware store and buy the appropriate number of small washers, preferrably stainless steel, with inside diameters corresponding to the new rivet's diameter. Be sure to take a rivet with you to size the washers. All your brake shop has to do is place those washers on the inside of the shoe, drop the rivet in from the lining side, pull the trigger and, bingo, you'll have a good tight fit. The shop went so far as to drill all of the holes in the shoes to one consistent size so every rivet got a washer. It's a very neat job when done correctly. Our shop also suggested arcing the new linings to ensure a true 360 degree arc for maximum contact with the drum surface and longer life in general.
By the way, don't ever used bonded (glued) linings!
For the most part, BMW equipped Isettas with the Bing 1/22/98 carburetor. If you're wondering how they came up with the model number, Bing tells us that the "1" is virtually meaningless, the "22" refers to the venturi size in millimeters and the "98" points to a 300cc BMW (as opposed to British, Iso, Velam and Romi)Isetta. Bing also refers to this particular carb as a Type 121, used on the 300cc models. According to Bing's manual, variants of the 1/22/98 that were also used on 250 and 300cc motors are as follows: 1/24/49 (250), 1/22/97 (250), 1/22/131 (250 & 300), 1/22/161 (250 & 300) and 1/24/93 (300). With the exception of the main jet, jet needle and clip position, all other parts are virtually the same.
It's a simple little device that seems to work well if cared for but can give you fits getting it dialed in. We're not professing to be Bing experts here, mind you. As of this posting, we're speaking largely from consistent input we've gathered from other Isetta owners along with our own experiences.
Our carburetor came in two Tupperware bowls stuck to the bottom in gasoline residue. The fuel bowl was missing along with other parts. Fortunately, the carb body and guts were there. That's important given the fact that new Isetta carbs are not to be had. You either send Bing your core for rebuilding or swap your core for one of the suppliers' rebuilt units. If you hit in on the right day, you might get lucky and find an NOS/rebuilt unit up for bid on eBay.
The Bing Agency operates a facility in Council Grove, Kansas. Their phone number is (800) 309-2464 (orders only) or (620) 767-7844 for pre and post-sales tech information. You can check them out on the Web right here. They do nothing but Bing work and they do it very well. Our carb took right at a month from start to finish. We got the works ... actually, we had no choice. They bead blasted and clear coated the carb. All internal components were replaced as well as an external appearance kit (it needed it!). They had the missing fuel bowl (ouch!) which was installed and tested. We even got a couple of feet of their clear alcohol-proof fuel line which doesn't require any clamps. If you're into doing it yourself, you can buy the rebuild kit and owner's manual from them at a reduced price, too.
When the engine was rebuilt and fired for the first time, it started right up and the carb seemed to be dialed in. As the motor warmed up and began sounding even stronger, we noticed that it was running a bit rich due to the subtle presence of sooty, black exhaust while bringing the revs up. Then came the leaks. Seems like this is a way of life for Isettas. The gaskets were brand new and looked OK but leaked fuel just the same ... not a good thing.
Terry Sayther of Terry Sayther Automotive suggested that we pull that fuel bowl assembly off and check the mating surfaces to make sure that they were flat. It was a fast and easy process to determine that the surfaces needed some attention. We put a piece of 600 grit sandpaper on a flat work table and gently worked the surface back and forth for a few passes. A visual inspection revealed the obvious peaks and valleys that were causing the problem. We continued the sanding process until the major descrepencies were gone, added a light coat of Blue Magic Polish to the sandpaper and worked the surfaces to a mirror finish. Back on the car, it was dry as a bone ... all in about 10 minutes. You might want to consider buying a backup gasket set from Bing and keeping them in your service spares. The individual gaskets are all under a dollar. They're also included in Bing's rebuild kit.
Now to the running-rich problem. There are several areas to check in regards to this foible. First, pull the jet needle out of the slide pot and make sure that the e-clip is installed on the second notch from the top. There should be a total of four notches in this long, slender, tapered piece. The top notch is the leanest setting, fourth (bottom) notch being the richest. This setting affects mid-to-upper range power and that's where we saw the sooty jetsam eminating from the muffler. If you didn't replace that jet needle, get a magnifying glass and take a look at the area of the needle that seats with the jet. If that needle is an old one, there's an excellent chance that it's pitted. If that's the case, throw it out and replace it with a new one from Bing. When rebuilding your carb, make sure you get the start and idle jets installed back in their original positions. They look identical and can be easily reversed. The start jet is a #55, the idle jet a #35. The #55 start jet goes to the back, or engine, side of the carb. The #35 idle jet goes to the outside of the carb.
Next, you'll want to find the sweet spot between the idle speed and your idle air screw. The idle speed screw is on the left rear side of your carburetor with the slots facing down. There is a spring between the head of the screw and body of the carb. Turning the idle speed screw clockwise, or into the carb, will raise the revs. The idle air screw is located on the outside front of the carb and sits nestled just to the right of the fuel bowl. It uses a lock nut rather that a spring to secure it once properly adjusted. The factory calls for 1 1/2 to 2 turns out from the carb. Your engine will probably idle just fine regardless of where the idle air speed screw is set, unless it's all the way in, but will bog, fall flat on its face and/or backfire through the carb on acceleration if it's too far out.
We prefer a higher idle setting, somewhere in the 800-1000 RPM range. Our engine seemed to be happier accelerating from a dead stop with more revs at idle. Once you set your initial idle speed, you can turn the idle air screw in until you hear the motor start to decrease in revs. Now, back it out a bit and try the accelerator. You should get instant revs out of the the engine. If it balks, you might set the idle speed a bit higher and go through the same process again. It helps to have an associate manning the gas pedal during this procedure. Also, make sure the engine is warmed up for about five minutes before you get started. Trying to accomplish this with a cold engine is a fairly hopeless scenario.
One other area that can cause problems is the choke. Our choke seems to know when it drops below 65 degrees. You have to use the choke at about half-open for a few seconds, to get the engine started at or below that temperature. In warm weather, you never need to touch it. If your choke piston, or puck, is old and cracked, you can expect trouble and erratic performance. Make sure you replace this part. Bing part number 22-935 will run you all of $5.00. You can check yours by looking at the bottom of the piston and verifying that it has a small round indention in it. If it doesn't, it's worn out but you'll probably already know that from your engines cantakerous behavior, if you can even get it started to begin with.
The Cliff Notes on your Bing might look something like this: 1. Make sure the carb is super clean inside and out and has has all mounting/mating surfaces smooth and shiny. 2. Use all new gaskets. 3. Make sure all jets are free of any type of blockage. 4. Make sure your slide pot jet needle is smooth and shiny where it seats in the jet. 5. Make sure the jet needle is clipped at position 2 (from the top). 6. When adjusting, start with a higher idle speed and turn the idle air screw in until engine revs begin to decrease. Turn back out until the engine comes back to normal idle. 7. Check your choke piston and make sure it's making a good seal. 8. Make sure you have the start and idle jets installed in their correct positions.
9. Make all adjustments only when the engine is good and warmed up.
To throw you one final curve, if you continue to have performance issues after trying the above suggestions, like smooth acceleration, don't rule out timing, your spark plug, condition of your points, etc. Your carb is only one part of the equation. Don't 86 it until you know all the bases have been covered.
Personally speaking, the restoration of the Isetta chassis is one of the most gratifying parts of the whole project. It's also the messiest. Consider the fact that everything has been under the car for 40+ years and is plenty filthy by now, especially the steering knuckles, chain drive, engine and transmission. You can also bet that those brakes are shot too, particularly the wheel and master cylinders. Their innards have accumulated water over time and are probably rusted, or almost rusted, in place. There are some early before-and-after shots of our car's chassis posted on the Isetta Source site if you care to take a look at a fairly typical unrestored mess and what you can expect to get in return for your efforts.
There is no substitute for complete dismantling of the chassis and all of its subsystems if you're going the frame-off route. Once you have it down to a bare, and we mean BARE, frame you can have a nice powder coat job put on it and begin reassembling all of the original components that have either been cleaned up or replaced. All rubber items should be tossed in favor of new ones. You're well advised to replace all wheel bearings as well. These are $5.00-$10.00 items that can make a huge difference.
Rather than delve into each component here, please refer to the section of this page that is appropriate for the item(s) you are currently working on. For instance, if you go to the "Brakes" section, we will cover the disassembly, cleaning, rebuilding, reassembly and adjustment of same. Likewise with the chain drive, steering, suspension, etc.
Let's discuss the literal frame itself, though. This ladder-like backbone is one rigid unit. It's side rails are constructed of square steel tubing with round tubing at the front and rear. The second crossmember from the front is the rigid axle, also made of round tubing. The center crossmember is a U-shaped channel that the master cylinder bolts to on the driver's side. Finally, there are two curved steel tubes at the right rear that are your motor mount points and one at the rear in the middle of the frame that curves up and out with a t-shaped top bracket where the top of your rear shocks mount.
Once you have your frame void of any peripherals, you're ready to prep it for media blasting and paint or powder coat. In our opinion, go the powder coat route. You won't regret it. There is some minimal, but important, preparation you need to do before delivering it to your blasting/painting vendor.BR>
Clean, even lightly hone, the kingpin holes and put a light coat of waterproof bearing grease in them prior to the next step.
Plug the top and bottom of your front stub axles. Do this by putting a washer on top and bottom of the kingpin hole that completely covers it. Use a long bolt and nut to secure them.
Using the same method, plug the tube that houses your lateral steering shaft. This is the tube that extends from the steering gear box to the outside left front of your frame.
While not a show stopper, go ahead and put a small nut and bolt in the top, inside hole in your front motor mount tube. That's where your engine-to-frame ground cable will attach on the frame side. You need a good, clean connection to the frame if you want your engine to start.
One rule of thumb to go by here. Round up EVERYTHING you want to have coated/painted. On a side note, don't rule out small stuff you may have around the house, too. Think it through before you back out of the driveway. It's a lot cheaper to have a lot of parts done at one time than go back and have to pay a minimum fee (usually $50.00 or more per color for powder coat)if you've overlooked something or change your mind. Here's a list of what you might want to deliver to your vendor:
(2) Rear splash guards
(1) Splash guard mounting bracket
(1) Air cleaner canister (2 pieces)
(1) Engine cooling shroud (3 pieces including heater flap)
(3) Brake backing plates
(2) Shock towers
(2) Coil springs
(1) Tie rod
Pedal linkage cover
Other candidates might include:
Blower fan housing
Blower fan housing ring
Anything that can withstand 400 degrees for 30-45 minutes. No, your steering wheel is not a good choice.
The door is a project all by itself. There are more parts and more details that come into play than meets the eye here. There are aligment issues, door seal, silentblocs for the instrument panel, door piston, upholstery, hinges, glass, bumper, windshield wiper motor grounding, lock and trim.
We're going to tackle this subject starting with the dismantling of the door and building it back up from bare-bones. We'll assume that you've already taken the instrument panel, steering column, door piston, door handle and inside latch, upholstery, rear view mirror and fresh air duct (if you have the Deluxe model) out and the door is hanging there by its two hinges. It might do you well to shoot the door handle/lock assembly and hinge pins ahead of time with a product such as PB Blaster and let it do its magic overnight. Some folks have had a bear of a time with rusted hinge pins, for what it's worth.
Take a putty knife and scrape that old, farkled door seal off. Werner and Hans both stock new ones for you ... about $35.00. You can take a case cutter with a new blade and slowly, carefully cut the seal around the windshield and pull the glass out. There's just enough room between the lip of the door and glass for that blade. Be sure to remove that old locking strip first. Go ahead and remove the stiker plate from the door frame and keep it with the latch.
Remove those old silentblocs in the door's instrument panel mounting bracket. You might find it easier to do with the door still on the car rather than laying on a work bench. Using a heat gun, you should be able to work them out. Do not use excessive force or you can bend the tabs the silentblocs are mounted in. It is highly recommended that you install your new silentblocs at this time. Trying to do this after you have a shiny new paint job on it can be risky in terms of scratching things up.
Examine the tubes on the left of the door where the hinges pass through. These represent the two stress points on your door, especially the lower one. You may find that yours have been welded or have had some sort of reinforcement put in place due to this very factor. In retrospect, we wish we had fabricated a small steel reinforcement plate for our car's bottom hinge but that's water under the bridge at this point. Check to make sure that your door closes all the way and that there is no binding or obvious stress around those hinges. If you do, be sure to point it out to your body shop and have it corrected. It would be a shame to get that door painted only to find you have a problem with fit and/or closing properly. If overlooked, it can be a very frustrating problem to attempt to correct.
Now, with the aid of an assistant, remove the e-clips from the bottom of each door pin, pop the pins out and lift the door away from the car. Might keep a heat gun and some PB Blaster rust desolver handy in case you have a stubborn set of pins.
Finally, be mindful of the lip that runs around the outisde of the door. It's fairly stout but transporting the door with weight on that lip can bend it ... one more task someone will have to deal with.
Once the door has been dipped blasted, painted and is ready to install, it can be mounted back on the car for installation of the new rubber seal, hinges, handles and windshield. The key to the door seal is to make sure that you have a good, clean surface and use some serious glue. You might find that your glass man will have this and either do it for you or supply you with what you need. We've had lousy luck with anything with a 3M label on it, by the way. Especially that yellow stuff.
The seal itself is actually two pieces. The top, and much longer portion, runs from the bottom of one side of the door, around the top and down to the bottom of the other side. It has right angle cuts on the bottom edges.
The bottom seal runs across the bottom edge of the door and butts up to those two right angle cuts on either side. While most commercial grade glues set up fairly quickly, you can run a bead down the back side of the longer strip a couple of feet and carefully place it against the door. Cut your first right angle before you start. Have several pieces of masking tape cut and nearby so you can tape the seal in place. Do the next two feet and so on. Once you're all the way around the door, you can cut the second right angle before gluing the final foot or so into place. Do the same with the bottom part of the seal and close the door making note that the seal is centered all the way around. You'll still have time to make any slight adjustments. Close the door using the handle and lock it down tight leaving the masking tape in place. Let it sit overnight and let the adhesive cure. You should be able to remove that tape the next morning and have a nice installation to show for it.
Door Hinge Rubber Seals
After that new door seal is in place, you can put your new door hinge rubber seals on and install the hinges. The repro seals we've seen are made by Metro Molded Products in Minneapolis, are of very good quality and are available in the correct gray factory color. Those rubber seals have caused some confusion as to what-goes-where. The two larger diameter seals belong to the bottom hinge. You'll notice that one is sightly larger than the other and has a bit more of an angle at its base. That's the one that mounts to the body, the smaller one to the door. You'll know if you got them installed backwards because the flat base of the seals won't fit flush with the door surface.
The two top seals will be obviously smaller. The cone shaped seal mounts to the door and the elongated seal with one flat side mounts to the body with the flat side resting against the window drip molding. Snug those seals down around the bolt tubes in the body and door for a good, tight fit. Avoid using any type of sealant here. It's not necessary and might damage your paint. Insert your hinges after you've given them a thin coat of waterproof bearing grease and hand tighten them. With the help of an associate, have your greased hinge pins handy and fit the door to the body. Now you can pop those pins in. Leave the e-clips off for now. By the way, if you're pins are badly corroded, look into a new pair of stainless steel pins and e-clips through parts suppliers. The pair go for about $20 and are very sharp.
OK, you have your door painted, door and hinge seals installed and the door is back on the car. Now you can install the door handle/lock assembly on the interior side of the door, the striker plate to the inside tube frame on the passenger side, insert the door handles and make sure the hinge nuts are good and tight. Once this is done, you'll have your reference point for aligning the door. The goal here is twofold: Make sure the door closes flush with the tube frame all around and that the door lock closes just inside the edge of the striker plate without hitting it.
If you close your door and the "jaw" part of the door lock hits the striker plate, it's obviously too far to the right and needs to come back to the left a bit. This is accomplished with small aluminum shims that fit around the threaded part of your hinges. No two Isettas are necessarily alike. Some used no shims, some have shims on the bottom only, some on the top, combination of different shim thickness, etc. If you find that your door is too far to the right, placing a shim(s) between the body and the body hinge base will push your door slightly out or to the left, just what you want it to do. If you need to push the door to the right, you'll want your shim(s) to be between the door and base of the door hinge. That will push your door to the right. Play with this until you get it the way you want it. With two people to handle removing and installing the door, it doesn't take long to dial the alignment in. Once you're done, you're done.
This simple looking guy can pose quite a challenge. The door piston's primary job is to assist in opening the rather heavy door and, hopefully, keep it in the open position. As many of you have found, the inner spring has lost its oomph over the years and, while still useful in getting that door open, it also tends to let the door close on its own as well.
The piston has six parts: the inner and outer piston housings, coil spring, threaded retaining collar and two silentbloc/bushings. Replace those silentblocs while you have everything apart. If you order these, get six of them. These units are the same ones used in the drag link that connects the front of the chain drive to the rear of the frame. The other two cushion the rear of the instrument panel where it is bolted to the door.
The real issue here is that spring. First, if you take your piston apart, it is advised that you have an assistant to help steady the two parts of the piston housings once you unscrew the threaded collar. The spring compressor you used for the front spring tower/shock absorber removal is perfect for this job. Just place the piston in the compressor, crank it down until you can unscrew the collar and then back the compressor off until everything comes apart. You may want to shoot the threads around that collar with PB Blaster and use a heat gun to loosen things up a bit. Don't let that weak spring fool you! This thing packs a wallop and can turn into an unguided missile and do some serious damage if you're not careful.
There are several routes you can take in beefing your piston up. You can insert three 1/4" x 1 1/2" washers/spacers in the large end of the piston. This will slightly compress the spring to boost its lifting power but is not an eternal fix. You can add a gas strut inside the spring for additional boost, too. The cleanest approach we've seen so far is to order a new gas strut from Werner Schwark at Isettas-R-Us and eliminate that spring all together. The strut also eliminates all of that grease that goes along with the spring and saves a bit of weight, too. Werner has come up with the perfect setup that includes the washers that are threaded on at either end of the strut. It drops right into the piston housings, is smooth as silk and no assistant is needed to install it. Expect to pay in the $60.00 range for this unit.
Bubba Mace made one observation that you might make note of here. One of his housings had what appeared to be a thick wire soldered/welded into it which prevented his new strut from installing properly. Make sure the innards of your door piston are clean and clear from obstructions before proceeding.
One final detail on that piston. It may not dawn on you at first but be sure that the threaded collar securing both halves is screwed down as far as it will go. Why? Because that limits the piston travel when the door opens. If you leave that collar a few threads short, the piston will extend a bit farther and the door bumper will hit the left nerf bumper when the door is open. That's why.
The Isetta's Achilles Heel. They are also referred to as donuts and guibos (pronounced "gwee-boze"). These poor things twist around in a continous S-shape while moving up and down with the chain drive. You can see from this pic that they sit at a contorted angle when they're not moving. Spin 'em up, move 'em up and down and you've got a lot of stress going on. If you do nothing else, make sure that you a.) have a good set of couplings, b.) have the correct low-profile coupling bolts with the lock nuts facing the inside of the car, not on the transmission and chain drive sides and c.) have them good and tight and check them on a regular basis. At around $80.00 for a new pair, it's a bargain compared to the holocaust you'll have on your hands if an old one decides to buy the ranch on you.
Craig Vechorik installed a pair of couplings for a BMW 325 automatic transmission model on his daily-driver back in the early '90's. Isetta parts were hard to find so he went with the real thing as opposed to the shoddy third party units that were available at the time. Here's a pic comparing the Isetta coupler and the 325 unit. The beefier 325 coupler is part number 26 11 1 225 624 and retails for $57.50 each.
Hopefully, Jim Janacek, Isetta guru and cameraman deluxe, will shoot some footage of the drive couplings under power. He brought the subject up at the 2002 National Microcar & Minicar Meet. We hope he can find the time for it in the future. It would be interesting to watch the action.
Here's some more drive coupling input from our friend Richard Lewis:
If you have inspected the coupling flanges and intermediate shaft and found that some of the ears are tweaked, the parts should be replaced or repaired before you install new couplings and the special thin head bolts. Since the couplings already run at a slight angle, it is important to have the coupling mounting ears running true. This can be done by machine shops or drive shaft repair shops.
To many, this is a mysterious device. In reality, it's a big electromagnet and a good one at that. The Dynastart unit in your Isetta was manufactured by Bosch in Germany and carries their part number LA12-130-3R. There are many variations of this unit with part numbers varying slightly from the Isetta's number. One camp will tell you that these units interchange, i.e. the BMW 600 unit, part number LA-BM-12-130-3R, will fit the Isetta and vice versa. At face value, it would appear that some variations should bolt right on and work. The one's we've seen don't ... at least the BMW 600 unit. The round steel housing on that unit is deeper by a good inch or so and will not fit. You may stumble across another first cousin to the Isetta unit that is immediately noticeable in that the condenser is mounted next to the points. That unit won't fit either. We tried.
In a nutshell, the field coil housing has two staggered sets of coils, one larger group for starting and one smaller group for charging. This housing surrounds a heavy duty armature that is bolted to the outside end of the crankshaft. Starting the car is completely silent as there are no gears, springs or belts involved in the process. The voltage regulator sits in between the Dynastart and battery and monitors voltage levels during operation. A red light on the instrument panel tells the driver that the unit is in "charge" mode when the light comes on and in "battery power" mode when the light goes off. In an Isetta, if the red light comes on, that's good. When it goes off, that's good too. If it stays on, that's not good.
Here are a few things to watch out for on your Dynastart unit. First, many Isettas had their voltage regulators replaced, some with the correct Bosch or Noris units, some without. Many literally got their wires crossed and fried the leads from the regulator into the Dynastart field coils, the blue wire seeming to hold the record in this category. Cold or cracked solder joints where there is an electrical connection is another thing to look out for. This would primarily manifest itself where the coils are joined inside the field housing unit and at about 11:00 o'clock on the outside of the housing where your large yellow wire is fastened to a flat copper lead coming from the starting coils. While easily fixed, these can be hairline cracks that only rear their ugly heads once the engine heat rises or vibration breaks their connection.
While pretty bullet-proof, the armature can develop a dead spot and cause starting problems. We took ours to an automotive starter/alternator company and had them give it a once over with their growler. A growler is a device that looks for dead spots or grounds. As it is run over the surface of the armature, it should get a zero current reading if the armature is in tact. If it shows a positive reading, that tells you that there is a bad ground in the armature and a signal to get out your checkbook.
Any vintage automotive electrical system can be a real challenge, especially if it's been partialy burned up due to modifications that got ugly or a voltage regulator that went into fricasse mode. Just about every tatooed Isetta wiring harness we've seen had ignition problems of some form or fashion with the blue and green ignition wires vying for first place in the Meltdown Category. One of the prior owners of our car went so far as to put a 25 amp fuse (8 amp being normal) on the ignition circuit and apparently turned the car into a space heater for a few seconds. Another mod was the installation of a Radio Shack buzzer on the turn signal circuitry. It appeared that the individual(s) that orchestrated this upgrade took the "I wonder if it's this one? No, I'll bet it's THIS one" approach to wire splicing.
The Isetta wiring harness is divided into four parts, 1.) Instrument panel to Terminal Block 1 (mounted on the driver's side wheel well), 2.) Main harness from Terminal Block 1 to the rear of the car, terminating partially at Terminal Block 2 mounted on the firewall and on up the passenger side to the headlight and turn signal, 3.) Rear harness from Terminal Block 2 on out to the tailights and, 4.) Ignition harness which only has four wires and runs to your coil and Dynastart.
At best, your harness is probably filthy, some of the shrink tubing may be frayed or gone. Extra wiring may have been added as a work-around fix at some point in time. Before you begin dismantling anything, get a #2 pencil and piece of paper and diagram your wiring harness for future reference. Taking one harness at a time, carefully strip that covering off and give it a good warm, soapy bath. It has been noted that BMW was rather stingy with their wire so make sure that you keep everything in its original configuration (lengths) if you removed that old covering. You can placed a tie wrap around the wires so they stay put.
An old tooth brush will help knock all of the crud loose. Dry the harness off and recover it with some new, fresh shrink tubing. When you buy heat shrink tubing, consider that the off-the-shelf variety shrinks two-to-one. If it starts out as 3/4" tubing, it can shrink down to 3/8". Our car had barbequed ignition wiring which followed a path from the Dynastart, up the main harness and on up to the instrument panel. If you have the classic toasted blue and/or green wiring, just replace it with 14 guage stranded copper wire from your hardware store and you're done. Keep the colors the same so it matches with the published factory wiring diagram.
Brand new harnesses are available from both Isettas-R-Us and Hans Rothkegel and are faithful to the original color codes. For what it's worth, the new instrument panel harness we bought was wired backwards. In another words, the shortest wire on the factory harness was the longest wire on the repro harness. Thankfully, the new harness had a generous amount of wire in terms of length and hooked up with no problem.
Color Codes & Wiring Schematic
Isetta Tech would like to thank Mr. John Jensen for his generosity and permission to share his electrical schematic with the Isetta community via the Internet! With the exception of a few minor tweaks in appearance, the schematic that is linked here is the same one that is published in John's book "Isetta Restoration - A Guide For Restoring The BMW Isetta 300 US Export Sliding Window Model" on page 158. The color codes, found on page 157, are public domain. The schematic is copyrighted material and is used here with his permission.
John told us, as he mentioned in his book, that this schematic was one that matched his 1958 Isetta and may not be 100% accurate for all year models. This diagram matched our early 1957 Sliding Window Coupe 100%! The only deviation from this diagram on our car was the installation of a European rear center light. The simple wiring procedure for Euro light is discussed in this section under Wiring Up Your Lights and is not depicted in Mr. Jensen's diagram.
Here's the color code chart. Here's the wiring schematic.
Instrument Panel Wiring
This isn't the nightmare that it may appear to be. While the area under that panel is somewhat restricted, you'll find that there's plenty of room for everything. This is another one of those jobs that just requires taking things in the proper sequence to ensure success and minimal hassle.
More info coming soon.
Turn Signal Switch Wiring
You'll probably find that the turn signal switch wiring is going to be the most tedious part of installing job. There are a total of six wires, three top and three bottom, that connect to the switch. All six wires must exit the bottom of the housing without getting pinched by the part of the switch that rests against the steering column. You'll want to cover these wires with shrink tubing. So everything needs to a.) be hooked up correctly and, b.) be the correct length before you crank up your heat gun.
When it really comes right down to it, the top three wires on the turn signal switch are the ones you have to deal with as the bottom wires fall below the part of the switch that rests against that steering housing. Just connect everything and pull those top three wires down each side of the recess in the switch where they meet up with their bottom three buddies. Test your turn signals and headlights before you put the heat on that shrink tubing! Please don't get it all gussied up just to find out that you got your signals backwards. Also, when wiring up the top and bottom of the switch, remember that the switch levers point up, not down.
Just for the record, here's how you wire these dudes up, starting with your high/low beam switch: Top (two brass terminals, looking at it from the lever side, lever pointing up): Right terminal=White, Left terminal=Yellow. Bottom (single terminal): Yellow and White.
Turn signals go something like this. (Again, looking at the lever side, lever pointing up): Top: Rear terminal=Yellow and Blue. Right front terminal=Black and White. Left front terminal=Green and Black. Bottom: Rear terminal=Red and Black. Right front terminal=Green, Black and White. Left front terminal=Red, Black and White. Isetta guru Jim Janecek supplied us with these top and bottom shots for your viewing pleasure. Here's how the top should look. Here's the bottom. Speaking of viewing pleasure, why not take a break, crank up the volume and go for a 50 mph cruise with Jim in "The Peril Pod"!
Check the functionality of this before you clamp the housings to the steering column. If for any reason it's not right, you're not going to burn the garage down and probably won't blow any fuses ... it just won't work or you'll have the sides reversed. And don't forget, if the turn signals don't work correctly, don't blame the switches ... yet. The lights at the other end must be correctly wired for the circuit(s) to work. Troubleshooting can be as simple as making sure that the bayonet-style bulbs are firmy seated, checking for reversed wires and/or bad ground(s). Taking a breather from a snafu has fixed a lot of problems too.
Finally, let's take a look at the Bosch flasher like the one originally installed in the Isetta. Its current part number is 0 336 102 022. The box will also indicate its electrical rating as "12V (1+1)x18W". Isetta parts suppliers are rather proud of this little guy in that the going price is over $30.00. Frankly, you can jet over to Auto Zone or your local parts house and get one of their three-pole units for around $4.00. One flasher that's guaranteed to work fine is the Tridon F550 12 volt unit. It will probably be marked "Max 4 lights" as well. Some offer an "extra loud" flasher for an extra buck or two. Get the loudest one you can get your hands on. You may not know it yet but you'll need one. It's virtually impossible to hear it over the exhaust system so you tend to drive around town with one of your turn signals on and not realize it.
As far as correctly wiring your flasher up goes, your looking for terminals marked X (power on), L (load) and P (indicator light). No one at the parts store seems to know this. You'll connect your power lead (circuit 76, blue and yellow) from the fuse box to the X terminal of the flasher. Next, connect the short red and yellow (circuit 77) lead to your instrument panel indicator light on one end and the P terminal on the flasher end. Finally, connect the blue and yellow wire (circuit 78) to the flasher's L terminal and the top, rear terminal on turn signal switch on the opposite end. That should do it. You can always refer to the section on wiring your turn signals a few paragraphs above this one for visual clarification.
On a final note, if you go the Bosch route, you'll find the terminals marked 49, 49a and C. Based on the Tridon description above, 49 is 'power on' or X, 49a is 'load' or L and C is 'indicator light' or P. There's a small wiring diagram in German that's included with the unit.
Wiring Up Your Lights
In this section, we'll cover the headlights, turn signals, tail/brake lights, license plate light, Euro center light 'upgrade' and instrument panel. We'll address details about each lighting component that aren't obvious and don't jump off of the schematic at you. In most instances, there are pix linked to augment the text. We're gonna leave the actual wiring job up to you, armed with your trusty diagram and color code chart.
The headlights are standard-issue 7" sealed beam units that can be picked up at any auto parts store. Basic lights are under $10.00 apiece with the newer, and preferrable, halogen units ranging from $14.00 to $20.00 per copy. Check out the "Headlights"
section for the inside dope.
Your headlight wiring harness/plug assembly will snap right onto the back of your new lights and the stops on the inside of the headlight rings will fit perfectly into the corresponding glass 'bumps' on the outer back side perimeter of the lights to keep them centered once you've popped 'em back in the buckets.
The bullet-shaped front parking light/turn signals have three wires connected to each one of them. The tan wire connects to the outer grounding ring and is held on by the large nut that secures the bulb holder/reflector assembly. The other two wires are secured by screws in the bulb holder base. One provides direct power for the light, the other comes from the flasher for turn signal action.
The tail lights are just about as simple as the turn signals. The rear wiring harness makes its first stop at the right rear light. The reason we mention it is that you will have more than one wire connected to a given terminal, most notably the ground (tan) wires which continue on the the license plate light and end the journey at the left rear light as a single wire. If you should get everything wired up, turn your lights on and notice that one tail light is brighter than the other, you have the two hot wires on the brighter light backwards. One light thinks it's in "brake light" mode and the other is normal. Reversing those two hot wire should put that to bed. The rear bulbs are the same bayonet-type as the turn signal bulbs except they are clear as opposed to amber (assuming you don't have amber bullets in front with clear lights installed).
The license plate light is a European "festoon" lamp that is a cylindrical job with pointed contacts on either end. It simply snaps into its holder, gets a ground wires (41, tan) on one side and a hot wire (44, red and white) on the other. Doesn't matter which which color goes to which side.
While a tad off of the subject, you may find that the clear plastic lens for your license plate light has clouded up, cracked or is missing all together. You can fashion a new one with a small piece of plexiglass cut 1" x 3". Just drill two small holes in either end and get yourself a couple of small stainless steel self-tapping screws and spring/lock washers. That's about all there is to it.
The European-style center light was factory installed to meet the Euro safety standards, clearly 25 years ahead of the United States. US Export models had only a license plate light and a blank steel plate where the Euro light was mounted. This option can be purchased from suppliers as an upgrade for around $30.00 and is a good choice in our humble opinion. Wiring it up is a piece of cake. All you need is one wire running from either tail light (we recommend the left side, circuit 46) back to one side of your new light. Considering the fact that you already have a ground wire connected to the license plate light just below it, all you have to do it make a short jumper wire to the other side of the center light and you're done.
Here's one minor detail about that center light you might want to know. The standard festoon lamps you'll find in auto parts stores are the single filament variety, not multi-filament like your tail lights. What does that mean to you? It means that the center light is either on or off and will not get brighter when the brake lights are activated. If someone knows of a multi-filament lamp, please let us know the manufacturer and part number so we can post it here. A third brake light would be nice just for the price of a single bulb, and that ain't much.
The instrument panel lights are down right cool. Total simplicity in design and function. There are only four small lights here. The oddball is the speedo lamp that is a suppository shaped bulb and fits into the brass base of the speedo light fitting and glows a sort of sexy yellow. The other three, a psychedelic purple high beam indicator on the left, 7-Up-bottle-green turn signal indicator in the lower middle and red generator light on the right, complete the Isetta's lighting compliment. These are tiny bulbs, much smaller than the one used in your speedo. The link to the pic listed above gives you a pretty good idea of what you'll see but nothing compares to the real thing.
The ignition wiring harness consists of four wires, three of which go to the Dynastart and one that connects to the coil. The green wire (circuit 90) goes to the postive side of the coil. The blue wire (circuit 91) along with the black and red wire (circuit 92) both go to the Dynastart and the black wire (circuit 93) runs from the negative (condenser) side of the coil to the Dynastart.
When we refurbed our harness, the ignition wires were separated from the main harness and got fresh shrink tubing. It seemed easier to isolate these wires for future troubleshooting or repair should the Dynastart or voltage regulator ever cause a problem. We've seen more than one original Isetta harness and they all seem to have had problems in the ignition department, never with the lighting. If any of the lights should ever develop a problem, you'll most likely blow a fuse. If your ignition system ever goes fubar on you, the damage can be much, much worse.
If you take a look at the pic of the ignition wiring harness link at the beginning of this section, you'll notice the spade connectors that were added to our setup. By doing it this way, you can simply unplug the Dynastart for service and forego having to ever remove wiring from under the seat. It's your call on this one but it certainly works well and looks good to boot.
The other component of this system is the thick cable that runs from the A (or 30h) terminal of the voltage regulator to the Dynastart post. We soldered a large round terminal, large enough to accept a 6mm bolt, on the post end of this cable rather than leave the stranded copper wire. There is a hole drilled in the post that the stranded end passes through and is then secured by a bolt threaded in from the top. We chose to mount our cable, with terminal, on the top of the post. We'll see how it stands up to vibration over time and report our findings should this turn out to be a not-so-great idea. For what it's worth, BMW made this change on the 600.
FRAME (See Chassis)
Given that the Isetta has no fuel guage, it relies on the fuel tap for switching to the remaining .8 gallons of gas in the tank once the engine begins to sputter. Assuming you have a full tank of gas, NORMAL position for your the fuel tap lever is to the right, or passenger side. The RESERVE position is to the left and, when centered, the tap shuts the fuel supply to the carburetor OFF. This tap has been the scourge of many owners due to its penchant to leak. There is a cork seal in the threaded collar that screws on to the tank. There should also be a seal or O-ring in the threaded collar that secures the fuel outlet nipple as well. One other source for potential leaks is the fuel line. We used two feet of Bing's alcohol-proof line. This line really seals well and doesn't require any clamps. It's also clear so you always have a visual for fuel flow, air bubbles/pockets, etc. You can even dress that engine compartment up and go with some of their clear blue line, too. At less than $2.00 a foot, it's highly recommended.
Probably the single biggest "leaker" is the tap itself. BMW used cork seals in the construction of this device and that old stuff is long since shot. At some point, a previous owner of our car just pulled the whole thing off, silver soldered a brass nipple in its place and sealed it with what appeared to be the world's largest glob of black Dubble-Bubble chewing gum ... very nice. Unlike your Bing carburetor, you can buy rebuilt, original taps outright although it's less expensive to have your existing one rebuilt. Parts suppliers can fix you up with a rebuilt tap or you can send yours off and have it done professionally. Craig Vechorik, owner of Bench Mark Works in Sturgis, Mississippi, can handle this task for you. See the Services Section for contact info.
The tap lever will require some behavior modification on your part. Many Isetta owners fail to turn the tap to the OFF position when they stop their car only to come into the garage the next morning to the smell of gasoline. Your Bing carburetor is not going to help you here. You must turn the fuel supply off to restrict any gasoline from flowing into your carburetor when not in use.
On a final, related item, be very mindful of the route your fuel line takes from the bottom of the fuel tap to the inlet on your carb. Keeping in mind that the Isetta employs a "gravity fuel pump", you'll want that line to be as short as possible and running downhill the whole way. It doesn't take much of an uphill kink in it to foul up your fuel flow to the carb. Leave just a little slack to allow for the vibration of the engine. Our line exits the fuel tank nipple in a line towards the carb, in front of the right rear mud guard, over the top of the mud guard/air cleaner canister bracket and on down to the carb. The carb's fuel inlet nipple is tilted slightly upward. So far, so good.
Now here's an exciting subject! Our car came with a locking BMW gas cap with no keys. Nobody was able to open it. Since it was in pretty sad shape anyway, the lock cover was cut off and guts removed. A new repro cap came from Werner Schwark and fits perfectly. The repro differs from the original in a couple of ways. One, it is all black with the BMW logo in the center. The original, non-locking cap, had the black, white and blue BMW roundel in the center and was very sharp looking. Second, under the top side of the cap, the original had a small piece of metal attached just under the ventilation hole in the center of the cap. This kept gasoline from splashing out of the cap and onto the paint. These sort-of-repros do not have this small, but important, detail. If someone out there can offer up a safe, effective solution, please let us know and we'll update everyone on the matter.
If you want something a little different, Bill Darland has mentioned that a John Deere riding lawn mower gas cap, with built-in gas guage, works like a champ. Might be fun to call the parts department at a JD dealer and ask for one of a gas cap for an Isetta and listen to the ensuing hilarity.
Note: Our thanks to Isetta owner Richard Lewis for submitting the following information.
Isetta gas tanks can have rust problems. If you rebuild your carb and don't check the tank for rust, you could undo much of your hard cleanup work on the carb when you open the tank valve and pour tiny rust particles down into the little fuel filter bowl. A source for gas tank restorations is Mattson's Radiator in Stanton, Ca http://www.mattsonsradiator.com/) they are familiar with Isetta gas tanks and will charge between $89.95 and $129.95 for a tank restoration. The price will vary depending on the tank condition and if you need the exterior finished also.
If you want to save money and can refinish the exterior yourself then the interior can be treated with Kreem fuel tank cleaner (2 part) and liner. The liner product will seal the tank and even take care of small leaks. Kreem is available at motorcycle shops or via mail order for about $30. If you want to pre-clean out a rusty tank before you use the Kreem cleaner and liner product, pour in strong TSP solution and about a cup of BBs or small ball bearings and shake the tank vigorously. This should knock off the loose rust flakes. After the second or third repetition of the TSP/BB bath you should notice the rust is almost all broken loose and the rinse water is clean. Note that the gas tank filler actually protrudes slightly down into the tank making it hard to get the BBs and TSP solution back out through that opening. Drain these out via the bottom tank outlet. A few minutes of tipping the tank back and forth will remove any fluid and BBs.
Yes, you can still buy 7" sealed beam headlights. Here's a great way to upgrade a very important part of your Isetta. Sylvania, among others, has several different 7" halogen lights, one of which is their Cool Blue series. These burn brighter than a conventional sealed beam unit but aren't literally blue. Auto Zone also has their own brand that is more of a blue if you want that European look and stay street-legal in the process.
Expect to pay in the $12.00-$18.00 apiece range depending on the model you get. More money, more light, more blue. Yep, the connectors on the back are ready to plug and play. Just place the new light in your headlight ring, pop in four or five retaining clips, plug it in and secure it to the headlight bucket. Legal in all 50 states too. See Sylvania's Web site for product info then visit your local auto parts dealer and snap a couple up.
To properly aim your headlights, park your car on a flat surface. The front of the headlights should be 16 feet and 4 inches from the wall you'll be shining your lights on. Mark two spots, left and right, 25 3/4 inches from center and 30 5/8 inches up from the ground. You can use magic marker dots on the wall, pieces of tape, thumb tacks, wads of Dubble Bubble chewing gum, .45 caliber bullet holes, etc. for your targets. Those are the spots that your bright lights should center on. Adjust those brights by loosening the hollow bolts that hold the headlight buckets to the car and center the beam on your target. Tighten them down and switch to low beam. You should see the brightest part of the beam shift slightly lower and to the right.
Here's an early drawing that depicts the metric distances required for proper alignment.
The Isetta heater's effectiveness has been described as that of "a dog's breath". Most cars have deteriorated (or missing) paper hoses and cardboard heater covers on the under-seat unit and a shot rubber air hose connecting the engine cooling shroud to the heater input 'can' on the rear of the firewall. The original heater flap knobs are, for the most part, gone and/or replaced with whatever would fit. Ours had a trendy red kitchen drawer knob mounted on it.
If you have the core components of your heater, it's another cool project to jump in to. It's simple enough to have the under-seat heater unit, firewall can, diverter flap adjusting lever and windshield vent media blasted and repainted. The factory color used on heater components was silver. Items you'll have to deal with are as follows:
Heater output hose
Rubber hose from engine cooling shroud to firewall can
Cover for underseat heater unit
Small items such as the diverter flap knob and grommets
For lack of a better description, the original heater output hose was an aluminized paper material which time took its toll on. All but four inches of ours was gone. This hose was also the haven for small creatures that found their way into primarily garaged Isettas. Several skeletal remains have been reported by owners during the dismantling process.
New heater output hoses are readily available from suppliers. Isettas-R-Us offers a truly sharp hose that will compliment any interior with its textured fabric-like tan finish. You can also go to JC Whitney for their fresh air vent hose that resembles a slinky toy covered in black plastic. You'll want the 1 3/4" variety. The only downside to the JCW hose that we found is in the area that the hose has to pass behind the shift lever. It's just enough 'fat' that the shifter doesn't seem to have enough room to smoothly move in the third and fourth gear plane. It's tight any way you cut it. Werner gets $15.00 for his hose and JCW gets $20.00 if that matters.
One other hose-related item to consider is one-piece versus two-pieces. The only real issue at hand it where the hose passes behind the left side seat frame in front of your spare tire. If the seat is adjusted all the way to the rear, you'll probably pinch that hose and restrict an already wimpy air flow. That's where the two-piece approach comes into play. Werner sells his hoses in this fashion and for that reason. What's not included is a coupler. Keeping in mind that you're dealing with a 1 3/4" diameter hose, you can fashion one from a short piece of PCV pipe or snoop around the closet where your wife has the wrapping paper stashed. The cardboard roll in the center of the wrapping paper is darn near perfect. Cut a 6" section of it off, dry fit it to the hoses to make sure it's a good fit and then glue it into ONE hose. You can put a hose clamp on it and gently tighten it down to get max contact for the glue.
Make one of your hoses long enough to run from the heater output tube and over in front of the rear seat frame. Your other, longer hose will run from there, through the bottom rear of the driver's side panel and to the front, exiting in the side panel hole just under your windshield heater vent. Now, you have a quick disconnect under the seat should it have to be removed for maintenance purposes and you've circumnavigated the pinching problem associated with that one piece hose.
Werner has also taken the initiative to tool up a nice cooling shroud-to-firewall-can hose. Just a couple of stainless steel hose clamps from your hardware store and you've just knocked out one more problem. By the way, last time we looked, that hose ran around $65.00. Some owners have used that same flexible hose mentioned above, but a larger diameter, to keep costs down.
The cover for the heater unit can be a bit more of a project. The original was something like two rectangular cardboard trays with a raised lip around the edge, sorta the same form-factor that you get ground hamburger meat on at the grocery store. The top and bottom pieces were stapled together to cover the center section of the heater unit that is drilled full of ventilation holes. We've never figured out why the heater wasn't just solid, stamped sheet metal to begin with. Perhaps the expanded metal was easier to form in the manufacturing process. Who knows? Short of trying to duplicate the original covers, we did something different.
You know those windshield sun shields that are planted on folks' dashboards? That material is perfect for the job. We got the smallest one we could find for around $5.00. It looks like aluminum foil with a thin pad inside. You'll want to take the likes of a grocery sack and make a template to work from. The area where the heater unit curves around on the front passenger side and corresponding back side is the part you need to practice on. Once that template is done, just transfer it to your sun shield and mark it off. Deliberately cut it a bit on the large side so you can trim it up nice and neat. Grab a roll of aluminum tape to fasten the seams and you're done. Looks pretty cool for something nobody will ever see.
Now to the small items. To the best of our knowledge, that knob that fits on the end of the long skinny flap lever (the one that pokes out from under the seat) is not a readily available item. We found one in a VW/BMW/Audi junk yard on an old VW bus. We had to buy the whole turn signal assembly since that knob was glued on tight and wouldn't budge. We finally got it off, cleaned it up and painted it with Krylon Appliance Epoxy (see Steering Wheel section). Looks great and is the same look and feel of those bullet shaped high/low beam light and turn signal knobs on your steering column. By the way, if you get real lucky, the same basic knobs were used on the BMW 1600. Those knobs use a 4mm thread so you'll have to re-tap them for 5mm to fit.
One other potential challenge are the two grommets that the heater flap rotates in. These dudes are made of layers of cardboard and may be flaking apart, like a croissant, if not totally shot. If they're missing, you can get a couple of new ones in the plumbing section of your local hardware store. You'll have to make a cut on one side so it mounts flat against the flange where the heater vent mounts to the main unit. This keeps the grommet from turning. If you have your original grommets, just coat them with some epoxy and let it set up. That should do the job.
Finally, be sure to make a good seal to go between that firewall can and the firewall itself. You don't want any engine compartment fumes finding their way into the cockpit. Thick cardboard or 1/8" neoprene rubber stock will work here. Just use your heater can for a template to mark the outside diameter. Cut the inside diameter about 1/2" inside that and punch three holes with a standard-issue hole punch and your done.
Here are a couple of shots of the finished product right here and here.
Isetta horns were supplied from various OEM suppliers. Ours is an Artes unit from Barcelona, Spain. It was surprising clean inside given that it spent its whole life under the car. The horn mounts under the slanted portion of the front floorboard via steel bracket and is angled down and slightly forward when secured. Two wires descend through the floorboard just behind you steel tube door frame, one tan (ground) and one green and white (hot). If your horn wire posts are threaded with nuts and lock washer, be sure and solder a round terminal on each of those wires and make sure that big honker doesn't lose its connection.
Speaking of connections, or lack thereof, here's a problem we had and the solution to it. As previously mentioned, our horn worked when the car was dismantled. It didn't when we re-installed it three years later. Even though the horn circuitry is goofy to say the least, there was no doubt that everything had been restored properly. Just to be sure, we checked everything from the copper grounding ring on the horn button bezel for proper contact, the position of the carbon brush on the brass steering column ring, correct wiring ... you name it. It didn't work.
The fix? It was so seemingly insignifigant that we looked right at it and missed it the first three times. The horn has three basic subassemblies, the base, the center plate that the magnet contact mounts to on the bottom and resonator plate mounts to on the top and the chrome cover. The bottom of that center plate had a thin paper gasket on it that we thought was a seal. Part of it had deteriorated like an old piece of newpaper and fallen off. Turns out, that paper gasket is an insulator. It's absence creates a dead ground. Dead ground, no sound. We put some masking tape around the base unit and reinstalled everything. Bingo! You can either trim that tape up with an Exacto knife or make a neat insulator with new gasket material. Whichever route you go, just make sure it's there and your presence will be known when the occasion arises.
If your factory unit doesn't honk loud enough to relocate those four wheel drive Suburbans and Roadmaster Wagons into a bar ditch, you can check this Hella air-raid-duo out at Griot's Garage under the Accessories, Exterior tab or search on part number '77573' or 'hella'. These are mean looking little guys that are the same basic form factor as the original Isetta horn except you get two instead of one in this $70.00 package deal. Were talking 118dB here, just slightly less than a Motley Crue concert. Each horn is tuned to a different frequency (300Hz and 400Hz) so you're doin' it in stereo when you punch the button. The horns we've seen use a standard male spade lug connector. You'll need to put a couple of female connectors at the ends of your two horn wires and make a short pair of jumper wires to connect horn #2. They should also have female spade connectors. Just add a two-terminal spade connector to horn#1, connect your wires and your set to create some commotion. Griot's phone number is 800.345.5789 if you need further clarification on the matter.
If that's not good enough for you, check out The Auto Barn and search on "horn". The've got everything from 2 3/4" 100 dB units to the coveted Wolo Animal House 35 Sound Electronic horn. We're talking max entertainment with selectable animal sounds, 10 different sirens (hire a good lawyer before you use this feature), 16 musical selections and a built in PA system. This incite-a-riot unit is under $50.00, less than your public nuisance fines and court fees will be. You can also go for an off-the-shelf unit from the auto parts store if you're on a budget. You'll probably want a horn in the 4" diameter variety. Finally, you can also check with suppliers and keep that factory look/sound too. Original horns tend to be plentiful and reasonably priced. Whatever you do, use your horn prudently!
INTERIOR (also see Upholstery)
In this section, we'll discuss everything in the Isetta Sliding Window Coupe interior that is not upholstered. To read about your options and how to go about it, please refer to "Upholstery" farther down this page.
One third of the Isettas interior is the paint job. Make sure your body shop paints everything! If nothing else, you've just added more years to your car's condition by giving every square inch an extra layer or two of protection. Very small bits and pieces of the body will show once your car is back together so don't let your paint people cut any corners on this one. Make sure they paint the outer (larger) part of your door piston, the complete inside of the door, the sunroof frame, the engine access panel, your air plenum (if you have a Deluxe model) and of course, your instrument panel.
While a few of the following topics are covered in other sections, we'll mention them again for the sake of redunancy. Your sunroof frame can be bolted back in the car along with its handle and spacers. If nothing else, it will get the frame out of your way and keep it from getting scratched. Make sure that the front underside of this frame has some sort of temporary padding on it so it doesn't scratch the roof of your car.
One potentially pesky little part(s) are the clips that are riveted to the roof that hold the sunroof clips in place if you're only going to partially open the roof. The clips, along with your window latch striker plates, require the same small rivets to fasten them back in place if you want the job done right ... just like the factory did. If you removed the spring steel swing arms on your sunroof frame to have them chromed or painted separately, ditto for those two pieces. These rivets are not easy to find! Pop rivets aren't the answer either since they protrude out on one side. The closest thing we found, short of having to buy a whole new riveting system, were the type used to fasten brake lining on the brake shoes in that the rivet flattens out on each side. This will probably require you taking your car to a brake shop for a 90 second service call unless you can find someone who will let you borrow their gun for a little while. Good luck on that one ...
When riveting those window striker plates on, just make sure that the bottom of the plates are resting on the window sill ... as far down as they will go .. and that they are level. If done incorrectly, they can potentially have an effect on your window latch(es) ability to lock properly. That striker plate should be on the outside of the sill with the dog-eared part to the outside and front of the car. The "pretty" side of the rivet should be on the inside of the car as the other side will be covered up by your window channel felt once it's in place.
Once this is done, you can install your plastic window sill trim along the bottom. Make darn sure this is in place before you put your rear window rubber seals in. It's a very tight fit and attempting to do this after the fact could be a real wrestling match. You can also install your trim around the perimeter of the sun roof cutout. If you have those small sunroof clips riveted into the roof, just cut one piece of trim to fit between the two clips and run the rest from the outside of one clip, around the perimeter to the outside of the second clip for a neat, seamless job. Simple, effective and easy to put on.
Next, you might want to install your refurbished shift mechanism. This subassembly an interesting one and an easy job to clean up. More detail on the process is discussed in the "Shift Linkage" section. The following text assumes that your tube has the heater and choke levers installed, is lubed and ready to go. Feed that shift tube in from the inside of the car, through the hole in the left side of the firewall. Fasten the front down with three nuts and bolts. You'll need another person to get under the car to help you bolt the rear L-bracket onto the back, left side of the spare tire well. Now, you can fasten the rear of the tube to the bracket. We'll discuss the swivel and return spring on the rear of the shift tube in the "Shift Linkage" section as well. Make sure that both front and rear mounting points are good and tight. The shift linkage can tend to be sloppy on a good day so make sure that tube is secure. While your under the car, go ahead and install your rubber shift boot and secure the firewall (forward) side of it with a hose clamp.
If you haven't already done so, now would be a good time to install new rubber grommets in all pass-through holes in the firewall. These are off-the-shelf items your hardware store should have for you. You'll need a total of six. Five of them should be pretty much the same size and will accomdate the heater and choke cables as well as the three holes on the bottom of the passenger side where your wiring harness and starter cable exit. That sixth grommet, the one that's in the bottom of the spare tire well, is slightly larger as it must accomodate the thicker hand brake cable. The only other grommet on the firewall side is the one that fits inside a round steel cover where the speedo cable passes through to the engine compartment. The one on our car just needed a hot, soapy bath and was ready to to. This one might be more of a challenge to find due to its larger diameter.
Pass your heater and choke cables through the firewall. Hook the respective front loops around the outside of the control levers. Your shorter cable is for the heater and attaches to the longer, bottom lever. The longer cable is your choke cable and attaches to the the shorter, top lever. Slip the grommet around your speedo cable, pass its steel outer cover down the cable and feed the it through the firewall. You can now screw that outer cover down with two small sheet metal screws. Your handbrake cable should already be attached to the rear brake. Feed the front of that cable through the firewall into the cockpit and leave to one side for later installation on the hand brake mechanism.
One very nice detail is the addition of a new serial number plate. These can be ordered and stamped with the serial number and year-of-manufacture of your car. Place that new plate on the interior side of the right front wheel well. Pop rivet the two bottom holes first. It will become obvious that your new plate, being flat, will have its top holes slightly above the top holes in the wheel well. Simply take the rounded handle of a screw driver, cover it with a soft cloth, and gently press the plate into the lateral bead in the wheel well, just like the factory did. This will bring the top of the plate down a tad and should match up with the top holes. Now you can rivet the top of the plate in.
Your under-seat heater can be bolted in now. Nitty gritty details on refurbishing the heater are discussed in the section above by the same name. This is another two person job. Make sure you have a good seal between the can on the engine compartment side of the "can" that mounts against the firewall. Facing the heater inlet flange at the firewall on the inside of the car, start with the lower right bolt first. It's the tightest of the three. Don't tighten anything down until all three bolts are installed. Once the main unit is secured at the rear, you can fasten the L-bracket mount on the floor with two sheet metal screws. Your hose(s) will come later.
Your battery box comes next. That box should have two ears, one on each side, for securing the battery. Suppliers can fix you up with the threaded side rods and a new top strap. If you're in do-it-yourself mode, A couple of threaded rods, wing nuts and a steel strap could be made up to accomplish the same thing. Those rods will need to be bent at a right angle at the bottom where they pass through the ears on the battery box. One other item to be aware of is the height of the rods. Ours were way too long. In another words, they stood up too high, almost to the underneath side of the seat bottom. We shortened our by about half and cut new 5mm threads for the stainless steel wing nuts. It is advised to either have your battery handy to put in the car or at least know the height dimension before getting started on those side rods. To finish things up, we put a strip of 3M Safe Step on the bottom of our steel retaining strap to cushion the battery as well as a neoprene mat for the bottom of the battery box. This was cut from stock neoprene rubber sheet available at many hardware stores. Around these parts, it sells for $3.50 a foot in is approximately 13" wide.
Now your voltage regulator can be bolted in. If you're still running the original VR in your car, you'll have two threaded mounting plates just to the rear of the battery box. Be sure and use lock washers because it is here that your regulator grounds. Some folks have even made up a redundant ground cable from 14 gauge wire just to make sure. That wire can run anywhere a good ground to the body or frame. The battery ground cable that attaches to one of the terminals on the rear right side of the regulator (position varies dependent on manufacturer but it always attaches to terminal 30/51 aka 30/B+)should be long enough to loop around the battery on the driver's side and fasten to a 6mm stud directly in front of the battery box. We used a stainless steel wing nut and lock washer here for a good solid contact.
Work in progress.
Your Isetta has three keys; ignition, door lock and engine cover. The cover key is a unique little guy, shaped like a thumb screw with a square end on it, but the same for all Isettas. Werner or Hans can supply one of these for around $10.00 plus postage. The ignition and door key can be made by any competent locksmith. The ignition blank is Taylor Lock Company number M73N. Your locksmith will need the key code number stamped on the face of the ignition switch where you insert the key. Should read something like "SH141". The door lock key is Taylor Lock Company number 62VB. The key code for the door lock can be found on the square shaft that the handles are attached to. Just take the inside nut off, slip the inside handle off and pull the assembly out from the front. You'll see the alphanumeric code on two sides of the shaft. It should be somewhat similar to the ignition key code but with the alpha part on one side, numeric part on another. The combined code should look something like GC7461. Go ahead and have a spare set or two made up while you're at it. Additional keys are cheap (insurance).
LIGHTS (See Electrical System)
Work in progress.
Work in progress.
There is no way we can write this up to everyone's satisfaction but we'll give it a try anyhow. Ask the next ten Isetta owners what they run in their car and you'll get ten different answers with a few footnotes thrown in. Viscosity, natural vs. synthetic, blah, blah, blah. The best advice we ever got was this. "You don't own a car. You own a motorcycle with a body wrapped around it. You gotta start thinking like that". This advice came from Perry Bushong, President and owner of BMW of Fort Worth. Perry has beaucoups experience with vintage BMW bikes and rebuilt our engine. Keeping in mind that we're in Central Texas where the summers get over 100 degrees and freezing weather is something that happens very few times in the winter, 20W50 motorcycle oil was the recommendation ... Belray, to be specific. Kendall was also touted but nobody we've asked knows where to get it in the Austin area. Other good competition motorcycle oil was also deemed acceptable, BMW included. Whatever you do, change your oil and air filter on a regular basis!
The transmission and chain drive run Belray 95W140 gear lube. This stuff, as the weight implies, is thick stuff, works well and is not prone to leak. A year and a half later, our car hasn't sprouted one drop of oil at either the trans or chain drive. If you're keeping score at home, the factory originally spec'ed 40W, engine included.
The final two units that get oil are your two steering knuckles. 40W was also the factory spec here. Just about everyone's seals have been worn out and that 40W has no place to go but out, all over the front suspension. Sure, new swing arm seals will solve that problem for a while but Perry came up with a much better idea. Instead of filling those steering knuckle reservoirs with 40W, pump 'em full of waterproof bearing grease. Not only are those swing arms lathered in lube but that grease ain't going anywhere. A nice touch, and the one that called our attention to this mod in the first place, is to drill a hole in the center of the filler caps and thread them for grease fittings. You'll want to use the angled type fitting so you can get a grease gun/hose to it for servicing at a later date. No leaks here yet either.
One interesting little thing you might want to do is to save a vial of your old motor oil and forward it to Petroleum Products Monitoring, Inc. for analysis. Theyre located in Athens, Georgia. Call them at (800) 564-3132 or email them at email@example.com . You can also visit their Web site at www.ppmoiltesting.com and order a kit online. Only the Shadow knows what evil lurks in the heart of your engine. Now you can find out for yourself.
Contrary to what you've read, Isettas have oil filters ... you!
OIL PAN DRAIN PLUG
Although it's a small item, you might want to splurge on a magnetic drain plug for your pan. At under $7.00, it's an inexpensive way to get a visual check on what's living down there in your engine's oil supply. The original BMW part number (11-13-0-007-163) has been retired. The new part number is 11-13-1-744-329 and should retail for around $6.50 plus tax. Give your local BMW bike shop a buzz and see if they have 'em on the shelf. It may be a special order item so plan ahead.
We learned a lot about automotive paint and the processes that are involved in applying it. And it ain't cheap either. Our cas was shot with a light, bright yellow base coat/clear coat finish. It's Glasurit number SY-045.5. Unfortunately, the Glasurit database cannot produce the vehicles this number was applied to at the factory, only how to mix it.
Without getting into the body shop part of the project too much, there are four different applications that go into a base coat/clear coat paint job. First, and probably the most important, is laying down a couple of coats of epoxy-based sealer on the bare, prepped metal. We had our car dipped, some have theirs media blasted. This sealer provides a hard shell around the metal and won't allow moisture to get to it. The most obvious reason is to keep rust from forming and another is to provide a base for any type of body filler that may be used to make those dents and dings disappear. Ever see body filler that's cracked? 10 to 1 you're looking at a car that never got properly sealed. Moisture got up under there and unraveld it from the back side.
The body work phase of the operation comes next. Once the filler has been applied, blocked and sanded, your car is ready for the second application, primer. With a good water-tight base to adhere to, the primer provides the surface for the color of your car. Many times, you'll see a body man spray black streaks all over the car. This gives him a baseline for the final blocking and sanding procedure and will show obvious low spots where the black paint is left in a given area.
Once the primer has been sanded and cleaned, it's show time. Your base coat paint dries to a satin patina, not shiny like you might think. Two coats usually do the job. Given that, our Isetta took about a quart and a half to paint ... less that we would have guessed. Given that this paint dries pretty quickly, the fourth and last application is the clear coat itself. That puts the gloss down. Once it's been buffed, you can put a coat of polish on it right away. Notice we said polish, not wax. Products such as Wizard's
Work in progress.
RUBBER PARTS AND SEALS
If your Isetta is like most, the rubber components are all shot, disintegrated and/or gone. Replacing these items will make a big difference in both performance and appearance. Let's go through the list and briefly discuss what you're looking for.
These pieces can usually be purchased separately or as a turnkey kit. The US Export Models were fitted with gray rubber while the Euro version was fitted with both gray and black. We chose black simply because of the yellow paint job. Although most pieces are available separately, we got the kit, manufactured by Metro Industries in Minneapolis. They make replacement rubber parts for all kinds of car, including the Isetta.
This kit includes rubber seals for the headlights, turn signals, door hinges, front nerf bumpers, driver's side rear view mirror, tailights, rear bumper/nerf bar and two seals for the rear air intake and license plate light pod. The pieces are of very good quality in terms of finish and fit.
We've were told by several knowledgable folks to refrain from using any kind of sealant, like silicone, with this rubber. The rubber will do the job all by itself if installed properly and you'll avoid ruining fresh paint too.
Other seals you'll need to buy separately include the front rubber seal for the sunroof. This is a unique item and can be sourced through Isettas-R-Us or Hans Rothkegel. A trim item worth noting is the welting that fits between the rear of the body and the rear bumper. It's a small item but really sets things off nicely when properly installed. You can either get these from suppliers in silver/gray or have your upholstery shop make some up for you. This is nothing more than vinyl material with a round plastic line running through it. The stitch is made right against the plastic line which produces a nice bead, the part you'll see once it's on the car. Have them make a three foot section just to be safe. You'll need to cut holes in either of the two scenarios and cut V-notches on the inside of the trim where it bends around the rear side of the car. For what its' worth, the shop charged us a whopping $5.00 to custom-make our welting.
Here's where everything will REALLY be a mess. Number one in just about everyone's book are those silentblocs in the tie rods, steering arm and left steering knuckle. They should be shot by now and are the number one contributor to the "Isetta Watusi" you may have heard about. That's the uncontrollable shimmy of the front tires at speed. All four silentblocs are be the same part number. The old ones press right out and the new ones press right back in with the use of a little heat from a propane torch or heat gun. One former Isetta owner noted that he blew off the silentblocs completely and had four bushings made from Delryn, a space age plastic that is just about indestructible. He said that the Delryn bushings also did away with any need for a steering damper as well. Check under "Plastics" in your Yellow Pages. You won't need much to have these made up. There's no need for an outer steel skirt but you'll need the center steel sleeve for a bolt guide.
In a tie for first are the drive coupling or donuts. BMW calls them guibos (pronounced 'gwee-boze'). Unless you know the age of these couplings, buy two new ones and make sure they are tightened down and stay that way. Suppliers have these for you at around $40.00 apiece.
Other items you'll want to consider replacing are those silentblocs in the cast aluminum drag link that connects the bottom front of the chain drive to the frame. Those things take a beating too and can sure help smooth out the ride. They're the same ones that fit the door instrument panel bracket and door piston, by the way.
Replace those seals at all four wheels too. The front uses O-rings at the swing arms and thicker round seals at the axles where they protrude through the brake backing plate. Your chain drive seals at the input flange will no doubt need replacing as well. You can obtain those individually or in a complete chain drive kit which includes all of your gaskets as well.
In the rear of your car, the rubber bushings at the bottom and top of the shock mounts are probably compressed and cracked. We got lucky and got a pair of left-over bushings from a muffler/shock shop, cut them in half and popped 'em right on. The bushings in the rear of the leaf springs should be pretty well fubar'ed too. You may need to tenderize them a bit by spraying some PB Blaster on them and letting it soak in to loosen any rust. Any hydraulic press can move these old timers on down the line for a fresh new pair. Have this done when you take those springs apart and have them blasted and painted. Makes a huge difference. See the "Springs" section for more on the subject.
Looking to the frame, you'll want to cut some 1/16" rubber pads where your body is bolted. There are two at the back, three on the axle crossmember. The middle pad is rectangular and the two on the sides are triangular. These can also be purchased as a kit but, in our humble opinion, they tend to be rather thick. That 1/16" rubber stock can be bought at many hardware stores by the foot. You don't need much. You can punch your holes very easily with a standard hole punch, too.
Additional rubber items include the two boots that seal off the clutch and accelerator cables where they pass through the front crossmember of the frame just behind where they attach to their respective levers behind the pedals. Kits can be purchased for rebuilding your master cylinder too and include that rubber accordian boot at the front of the cylinder. Werner Schwark has a nice repro heater hose that connects the input on the firewall to the cooling shroud. This is a one-of-a-kind hose in that is starts out square, makes a right downward turn and is round at the heater end. We've also seen simple flex hose used here with a couple of hose clamps if you're looking to save some bux and still have that heater hooked up. One more item you'll want to look in to is the accordian boot just behind the firewall that fits around the shift tube. This keeps noise and the environs out. It fastens to a round lip with a hose clamp on the firewall side.
Perhaps "Splatter Reduction Devices" would be a better term, huh? While hardly a factory option, you might feel a lot better about having a good set of seat belts in your Isetta. We popped a set of Andover Restraints' standard 72" lap belts in our car. These guys look like they're right out of a commercial airliner with a simple chrome buckle and release. Expect to pay around $50.00 for the pair plus $5.00 for the mounting kits plus shipping.We had heard these were a pain to install but didn't find that to be the case. Three point belts would, no doubt, be more of a challenge but we're not convinced of that either. Just more work to install.
The mounting kits are nothing more than two very large washers with accompanying bolts, lock washers and nuts. An optional L-bracket can be ordered for a few bux but we didn't see any reason to go that route. Your going to have to drill 4 3/8" holes in your floorboard for those mounting bolts to go through. The two outside holes will be about halfway between the outside edge of the frame and the seam where the floorpan meets the curved side of the car's body. Be cautious and use a drift punch to make your pilot hole and then proceed with your larger bits.
The passenger side of the car is virtually unobstructed from underneath. You'll need to pay a bit more attention when you get over to the driver's side though. Specifically, make sure you're inside hole is far enough back to clear the brake light switch on the rear of your master cylinder and any brake lines back there. Second, the outside hole on the driver's side is going to be directly above the muffler. Take your time here and do it right. Because of the clearance between the muffler and floorpan, we inserted our bolts from the bottom of the car with the threads coming up into the interior. You could also make a run down to the hardware store and simply buy short bolts too.
Installation is about as simple as it gets. Just put your bolt through one of the washers and insert it from under the car. That washer is primarily for reinforcement of your floorpan on the underneath side. Slip the seat belt floor anchor over the bolt threads, drop a lock washer on and tighten the nut down. That's it. Be mindful of how the belt will look once it comes up and across the seat bottom. You may prefer to have the tags/stitching on the bottom for a neater look so check aspect out before you crank things down.
You can also get additional installation tips straight from Andover's Web site. This is the same info that will be packed in with your new set of belts. With all that having been said, we sincerely hope you never need them!
The Isetta uses a different pair of shocks on the front and rear of the car. Both types are available through parts suppliers but stand advised that they are pricey ... and for no apparent reason. Your shocks can also be rebuilt.
The front shocks live underneath the triangle shaped shock tower and are the coil-over variety. The base of the shock had an eyelet that mounts into the front of the swing arm. If you're paying attention, you'll note that the eyelet is welded slightly off-center. Make sure that the offset side of the eyelet faces out when you install your shocks. Once you've bolted the swing arm end down, you can slip the coil over the shock making sure that they tighter coil windings are on the bottom. The stainless steel piston protruding out of the base of the shock should have three rubber donuts in place. These help absorb vibration when the shock is compressed.
Now is a good time to install a new pair of shock bumpers in your steering knuckles, too. Just pop the old rotted ones out and insert the new ones. Your shocks will push in on these bumpers when everything is back together. Before you install your shock towers,make sure that the piston is pulled up as far as it will go! Go ahead and put your shock towers over the coil/shock assembly and, using a spring compressor, crank each side down evenly until the top, threaded part of the piston is through the hole in the top of the tower. Now you can put the rubber grommet and washer on and secure both nuts. A front and rear nut and bolt through the steering knuckle in the tower base wraps it up. By the way, make sure that the nut is on the inside side of the tower. If you ever have to do this again, your bolts will come out to the outside of the car ... not possible if you get them reversed. Don't find out the hard way!
The rear shocks are very conventional little units.
While the Isetta's shift linkage seems simple enough in terms of number of parts, there are several adjustments that you may need to make if you're doing a frame-off job or just tweaking your car after having put some miles on it. The setup consists of a main shift tube that runs front-to-back from the driver's side wheel well, through a hole in the firewall and extends into the engine compartment about a foot. There is a sliding steel rod inside the front of the tube that allows the tube to move and pivot as you go through the gear pattern. The shift lever drops through a hole in the top of the tube and is secured by a round, threaded collar.
In the rear of the car, the main tube is shaped somewhat like a hockey stick. There is an arm welded onto the end of it that hangs down at an angle and faces the engine/transmission. There is a rubber bushing that fits into the end of the angled arm. Securing the tube just behind the firewall is an L-bracket that attaches to the firewall. This holds an L-shaped arm that pivots as the shift tube is moved while going through the gears. One end of the L-shaped arm is attached to the main shift tube with a pin that fits through a threaded clevis. The other end is where the front shift rod connects.
That front shift rod, shorter than its counterpart in the rear, runs from the L-bracket to the top, lateral shift arm on your transmission. That rear rod attaches to the end of the main shift tube "hockey stick" and runs over to the vertical shift arm on the trans. All connecting points have rubber bushings installed. If you have a running car but haven't paid any mind to it, you can improve your shift linkage movement, perhaps dramatically, by replacing all 5 of them.
Adjustment falls into three areas. The threaded clevis that's mounted to the main shift tube can be adjusted in or out to position the two shift rods in a perfect right angle with the transmission shift arms. Once this is done, it's unlikely you'll have to mess with it again. The other two adjustments are more critical to your success. Both lateral shift rods have clevises on both ends. On the transmission end, the clevises are welded on. On the shift tube end, they are threaded and provide your second and third adjustment points. Make sure you reinstall your shift arms with the threaded clevises to the outside of the car!
The shorter, front shift rod can be adjusted for lateral throw. It is recommended that you start with the clevis threads about halfway out and then tighten the lock nut down to secure it once you fastened the clevis onto the L-shaped arm it attaches to. If you find your trans popping out of gear, lengthen those threads a bit to lengthen the arm's throw and see if that does the trick for you.
Like its front counterpart, that rear rod adjusts the same way. Another adjustment comes into play here though. Besides just giving you the extra throw, or travel, the shift linkage needs to keep the car in gear, lengthening the clevis also adjusts the angle of the shift lever inside the cockpit. The longer you make the shift rod, the more it will push the shift lever out/away from the left interior panel. You want your shift lever to be more to the drivers side than the interior panel side. While you may have to pull it towards your lap to get reverse, having it too close to that interior panel can make shifting into third and fourth gear difficult if not impossible. Play with it and you'll get the hang. Our personal rule-of-thumb here is that longer-is-better to begin with. You can always back it down if need be.
A few additional related items include a bellows-like rubber seal that fits around the main shift tube at the rear and is secured via hose clamp to the outside raised lip around the hole where that tube comes through the firewall. Parts suppliers offer an excellent repro of this part. By all means, make sure this hole is not open in the firewall. Your exhaust system is both behind and underneath it! Play it safe and seal your cockpit up good and tight. You'll reduce the noise level while your at it too. One other item is a little spring that attaches to a small tab on the bottom rear of the main shift tube and to a similar tab on the side sheetmetal just in front of the rear wheel opening. The only job that spring has is to move the shift lever back across the H-pattern to rest on the interior panel side when not in use. The lack of the spring makes for a sloppy shifter so make sure you have one on your car. Just about any hardware store should have one of these for you at a buck or less.
Finally, as elementary as it sounds, make good use of waterproof bearing grease on all moving parts before you put them back together again. Don't hesitate to remove your shift lever and pack the front of the shift tube with it. It makes an incredible difference. Make sure your front and rear shift tube mounting brackets are cranked down good and tight. And don't forget the cotter pins in the steel pins that the L-shaped arm pivots on.
The Isetta's shift linkage will never displace the Hurst Competition Plus shifter in the annals automotive history but it is quite innovative given the way the car was designed. We've never seen the underside of a right-hand drive model but with everything on the opposite side of the car, it must be an equally interesting setup, if not more so. Use the above guidelines to fine tune your car and you'll be happy with the results.
'Silentbloc' is Isetta-speak for a rubber bushing with a inner and outer steel collar. Isetta's have three different size silentblocs. One fits the front tie rods and steering components. Another, smaller type fits the cast aluminum drag link that connects the front of the chain drive casing to the rear of the frame, both ends of the door piston and a pair that fit into the instrument panel mounting bracket on the door. The third and largest type fit the eye of the rear springs where the chain drive mounting bolts connect.
While the door piston/instrument panel fit aren't mission-critical, the two silentblocs that fit into that drag link are important. Why? Well, that short little drag link keeps the chain drive at bay while it's twisting and moving around under power. It's sort of like a fishing rod whipping around with an unhappy 10 pound bass on the other end. These two units are fairly easy to replace. Just apply a bit of heat to the drag link and press the old ones out, new ones in. Don't forget those two cotter pins through the drag link retaining bolts when you put it back in. We've heard of some cases of very loud noises from the rear of the car and rough ride, particularly in the 30-40 mph range. The solution in one scenario was installing a new set of drag link and rear spring silentblocs and a pair of new drive couplings.
Remember that wonderful black tarred soundproofing that was plastered on the interior of your car? Assuming you've removed it or had it dipped (which makes it vanish!), you'll want to replace it with a good sound deadener. Without this stuff, your Isetta will reverberate like an empty beer can.
One of the best known names in the business is Dynamat (www.dynamat.com). They make many different automotive products to make and keep your car quiet. Their Dynamat Extreme was highly recommended for the job. You're most likely to find it a one of your local car stereo installers. This stuff is pricey! Be sure to get the "door kit" as it will save you about 10 bux. It's four square feet for about $ 90.00.
You can do one of two things here: 1. Probably the most cost effective way is cut and install strips of it on the rear parcel shelf, firewall, sides and floor or 2. cover all areas completely for that limo-quiet ride. One way to save a buck here is to get a roll of sound heat shield insulation from JC Whitney and use this on the same surfaces, sides only, etc. A 48" x 72" roll runs $25.00. You'll need to glue this on yourself. Dynamat already has an adhesive backing.
Finally, if you're doing a frame-off job, have your body shop shoot the entire underside of your car, firewall, parcel shelf and side panels with 3M Rocker Schutz. This is the same OEM stuff that car manufacturers shoot the rocker panels on new cars with, hence the "rocker" part of its name. "Schutz" you ask? That's German for protect, cover, etc. It's amazing how much resonance this kills not to mention effectively giving your car a fresh undercoat. Has to add years of protection!
This will probably run you in the $175-$200 range. It has to be shot with a special gun and is sold through auto paint distributors so it's not exactly an off-the-shelf item.
US Export Isettas all came equipped with VDO speeometers calibrated in miles-per-hour. European counterparts were calibrated in kilometers and British-built cars were equipped with Smiths speedos. We weren't crazy enough to tear our unit apart and sent it to Palo Alto Speedometer instead. These folks do it all! They are an authorized VDO repair facility and even have the original screens for painting fresh dial faces on old, faded units.
Pricing runs around $175 for a complete rebuild. Having your face and dial re-screened will run you about that much again. We bought a new chrome trim ring for ours for a whopping $10 and used the original glass after giving it a clean up. Turn around time was a little over one month but plan on it taking a little longer just to be safe.
One item that's related is the small light bulb which just barely illuminates the dial face at night is available from Palo Alto or any auto parts store that caters to Euro cars. Another is the thin black rubber washer that provides a cushion between the speedo and instrument panel. We got ours at a plumbing supply store. It was perfect, especially given the big 15 cent price tag and the fact that the clerk told us to 'just take it and don't forget to come back and see us when you really need us".
The final part you'll want to look into is your speedo cable. Brand new cables are readily available and are exact replacements but unnecessary if you're cable is intact. Put a new blade in your case cutter of Exacto knife and cut off what's left of the plastic sheath that covers the Romex-like thin outer housing. Pull the actual cable from the outer housing. Wear gloves! That graphite-like lubricant is nasty! We took our cable and bare housing to a full service garage around the corner and put it in their carburetor cleaner bucket overnight. It was super-clean the next morning. Now came a fresh layer of shrink tubing. Use some waterproof bearing grease and lube the inner cable before you drop it back in the outer housing. That should take care of that.
The Isetta uses a coil-spring-over-shock design. There really isn't anything tricky here. You'll probably find that everything in the front suspension area is pretty grimy. In regards to those coil springs, we had ours blasted and powder coated along with all of the other chassis components.
The one detail that you need to remember when reassembling those coil spring/shock/shock tower assemblies is to make sure that the tightly wound coils are on the bottom, resting on the lip at the base of the shock absorber. Look and you'll see the difference in the top and bottom of those springs.
The rear leaf springs bolt to the rear of the frame on the forward end of the spring and the bottom of the chain drive casing on either side in the back. These springs have a large steel-clad rubber bushing that run through the eye at the spring's rear. Most bushings are cracked, hard and distorted. If rust is a real problem in removing them, grab some PB Blaster rust dissolver and let it soak in. You can pop 'em in a hydraulic press and punch those old bushings out.
If you're really going to do it right, you can take those springs apart, have them blasted and painted and put them back together looking like new. There are two steel straps, one towards the front (thick part) of the spring and one about halfway towards the rear, that hold the leaves together.On the underneath side of the middle of those straps is a small, round pin that only extends through the first leaf. Just gently pry the sides out so you can raise the strap up and shell those springs out one-by-one, bottom leaf first. Re-assembly is the opposite. Now is the time to press your new bushings in and replace any hardware, like the large front bolt, nut and washer, that you may need.
Once these springs are back on the car, you may notice that the spring on the engine side hangs just slightly lower than the left side. That's not a mistake. The spring mounting cradle on the right rear crossmember of the frame is welded at a slightly lower angle compared to its counterpart on the left. This preloads the chassis for the weight of the engine. If you look at enough Isettas from the rear, you'll notice that most, if not all, list to the passenger (engine) side just slightly. That's the reason, assuming that everything else on the car is in it's original place, hasn't been in an accident, etc.
Finally, there is one related subject that we won't go into depth to simply because we don't have enough specific information to work on. That would be retempering the rear springs. Isetta owners have done this in the past to compensate for age and wear 'n tear. Isetta Tech would appreciate any specific guidelines that could be passed along here. For instance, what do you tell the spring shop you need in regards to specifications? What are the costs involved? What is the downside, if any, of having this done?
Whether you're doing a frame-off resto or just systematically going through various parts of your car and upgrading as you can, you might consider replacing those old Grade 8 steel nuts and bolts with stainless. Keep in mind that while it certainly looks better and will withstand the elements much better that regular steel, never use stainless where anything has to be torqued down or is under stress. Stainless uses a higher content of chromium and doesn't pack the tensile strength that G8 does. For instance, don't bolt your motor mounts or rear springs in using SS. For interior use and small items, it's the ticket.
One of the best sources, besides a well stocked local hardware store, is Fuller Metric up in Canada. They've got it all! Check out their Web site at www.fullermetric.com. Their Vancouver toll free number is 800-665-4825.
Here's another project that can yield very gratifying results. Many Isetta steering wheels are showing their age. It's common to see cracks first appear in the area where the spokes meet the outer rim of the wheel. Some have been exposed to the elements and the outer rim has begun to pit and harden. Like other tasks, you have several options here. One is to send it off to a professional wheel restoration company like Gary's Steering Wheel Restoration. You can also purchase a steering wheel restoration kit like the one offered by Eastwood Company. You may be able to produce great results for the price of a few common items though. Unless your wheel is a real disaster, do it yourself. You'll get great satisfaction and the finished product is the payoff.
Our wheel was encased in not only the original paint, but three layers of gooped-on runny, gloss black enamel. That was actually a good thing in that the layers of paint sealed off the rubber rim from the elements. But it had to go. First, we used some Dad's EZ Spray paint and varnish remover. This stuff is killer! Be very careful to not leave it on the outer (hard rubber) part of the wheel too long and you won't have a problem with it. It took about three passes and a bunch of #00 steel wool to get it down the bare bones. Whatever the factory coated these wheels with is right up there with armor plating. Once you're done, you'll find that the outer part, as mentioned, is hard rubber, the spokes are steel and the hub is cast aluminum.
Once down to bare bones, wet sanded it with 420 grit sandpaper twice, gave it a warm soap and water bath and let it dry for a couple of days indoors. We wanted to leave the hub bare aluminum and had it polished to an incredible shine at a local polishing shop. If you're not going for a 100 point factory job, you won't believe the results!
Next, you can fill those small cracks in the wheel where the spokes meet the outer rim with JB Weld. Some folks get an Exacto knife and open the crack up a bit for a better fill and to rid it of any foreign material that might prevent a good, tight bond. Don't get carried away with this stuff. You're much better off to use it sparingly and make a second pass than to goop it on and have a contour sanding job on your hands later. Let it set up overnight and sand it to shape. Make your second pass if need be.
Next, mask off the hub and spray two light coats of Krylon Almond Appliance Epoxy paint (Part number: 3202) and let it dry for a week. That's right ... a week. Derusto makes a virtually identical product that some Isetta owners use as well, including painting their wheels, headlight switch, knobs, horn button, hi/lo beam and turn signal housings with it. Once cured, the wheel was wet-sanded three times, once with 420, once with 1000 and finally with 1500 grit paper. Don't worry if you cut through the epoxy in places. You just want to get a super smooth finish.
Next came the final coat(s). One note here and it's an important one! Read the instructions on the can of epoxy paint in regards to second/third coats. You MUST sand it down or it will look like wrinkle finish paint in spots when it cures and it will ruin your day. Been there, done that. Spray your final coat of epoxy on in smooth, deliberate passes. Krylon epoxy sprays on a nicely as anything your likely to find on the shelf. Just take your time and you'll impress yourself with the results.
Our car is a fresh resto so we can't speak to longevity but we do know of several people who have used the same method (it's not a process that we invented, in another words) and their wheels have held up very well over time. One member of the Central Texas Micronuts Car Club has an Isetta that has been a fairly regular driver for 8+ years and is just now beginning to show some signs of wear in the spoke/rim areas. Another Fort Worth Isetta had an identical repair process used on its wheel and is the nicest looking one we've ever seen although it was professionally sprayed with Glasurit epoxy sealer and Almond at the time the car was painted.
Some have suggested putting your steering wheel in an oven and baking it. One person will tell you 250 degress, the other will say no more than 125. We couldn't bear the thought of putting a nice steering wheel in the oven at any temperature. Besides, epoxy cures while paint dries. We're not saying it's wrong, we just can't get the nerve to close the door and push the button. Besides, we're bettin' that somewhere, someone's husband has probably spent a few nights on the couch for trying this.
Once the wheel's final coat had cured, we took some fresh #000 steel wool and gave it a very careful pass for a nice satin finish. We followed that up with a coat of Wizard's Shine Master Polish, a product that is great for any car. Note that it's polish, not wax, and is perfect for base coat/clear coat finishes.
Here's a pic of how that old gooped up mess looks now.
One more note on the subject. Before you put your steering wheel back on the shaft, make sure that the Woodruff key is perfectly parallel to the shaft and put some of that bearing grease on there to help ease it in. Makes the job a lot easier not to mention cutting yourself some slack if you have to pull it off again in the future.
The Isetta sunroof is so simple it's neat. You can raise it up and clip it to the small holders on the front of the roof opening for a fresh air vent. You can open it halfway for more sun and air or fold it all the way back for air tunnel excitement and a sunburn.
The sunroof components consist of a frame with a front steel crossmember that hugs the roofline and arms on either side that bolt to an adjustable bracket inside the car, just under the roof. Each arm of the frame has a 6mm bolt, spacer and nut attached to it to allow for proper clearance and securing it. A handle with a spring washer underneath is bolted to the center of the front of the frame for opening and locking the roof back down. A soft rubber gasket with a steel retaining strap holds everything in place in front. There's a center top bow (sliding window coupe, bubble windows have two)that fits through a small tab on each side of the sunroof material and creates a crown in the top for rain/water runoff and general profile integrity. Finally, there's a long, flat slender steel retaining piece that secures the sunroof at the rear of the roof opening. That's it. Those right and left brackets inside the car have a rectangular runway with a 6mm nut inside. This allows you to tension the sunroof to eliminate sags.
To get somewhat of a visual of how the material should be installed, think of yourself looking at the front of the frame from one side. From top to bottom, you have the sunroof material on top which curves tightly around the front of the frame to the underneath side, sort of a pouch. Beneath the material on the top, you'll want to have a strip of foam or padding between the material and frame top. Underneath the frame goes your rubber seal, covering the material, and then the steel retaining strap. That strap is held in place by pop rivets that are fastened from underneath the frame. That's the reason you want that top foam pad there. You may find that the rivet holes in the frame are too big for the rivets. If so, just grab a handful of small washers and glue them into the beveled holes on top of the frame first. Stand advised that the right and left corners are very tight and getting a rivet gun in there may be somewhat of a challenge but that's how it's done. To recap ... material, foam padding, frame, material, rubber gasket and steel retaining strap. Your rivet needs to pass through all of this so select a long enough pop rivet to do the job with a minimal amount "mushroomed" at the top of the frame.
One little touch you may want to consider is to take your front and rear retaining straps and use heat shrink tubing on them. It gives a very nice finish and, in regards to the front strap, gives it a softer finish and hopefully less of a tendency to scratch your paint job.
Top material is available through suppliers in either gray or black. Gray was the color the factory used on US Export models. We opted for black. Expect to pay in the $100 range for a new top. This material is from Germany and is very high quality. If we had to do it all over again, we'd have the upholstery shop do it all. Our top was cut a bit too tight around the front edges of the frame and had to be massaged with a heat gun to fit really right. We could have had one made out of similar German material (our shop does a lot of Mercedes/BMW work) for about $20.00 more and had it hand-made for our car. Installation charge is a wash unless your repro material is really off in which case it will cost you even more, something else to consider.
Once the sunroof is installed and tensioned, you shouldn't have to mess with it again except to possibly loosen those side bolts, push it forward a tad and crank 'em down again to keep it tight as time goes by. Just keep that handle tightened down as it tends to get loose with the opening/closing routine.
Factory trim around the sunroof opening was silver/gray and is available from suppliers. We went to JC Whitney for their flexible black adhesive trim which looks great with the yellow paint. On the inside middle of this U-shaped trim there is a small plastic line that is covered with adhesive so this stuff sticks once in place. And it conforms to curves and turns perfectly! You'll have to do some trimming around the window and sunroof latch plates but it's nothing an Exacto knife and some patience can't easily handle. This was also run around the inside window sills, top and bottom. Makes a really nice touch regardless of what color route you take. JCW sells this plastic trim in 50 and 150 foot rolls. It comes in black, gold and chrome. Price is around $20.00 for the 50 footer. Part number for a black 50' roll is 15ZJ9868B. Contact them at 800.529.4486 or www.jcwhitney.com. Your suppliers have the silver/gray trim for you if your keeping your car to factory spex.
One more bit of sunroof trivia before we move along. There is a right way to open this little guy. Follow this link for the ultra simple step-by-step procedure. The wrong way, which will flog your rear part of your roof and possibly trash your paint job over time, is also shown. Take a few extra seconds and do it right.
The Isetta has two stub axles that are part of the second crossmember of the frame. They are a fixed length. The camber and caster are fixed as well. A beefy cast aluminum steering knuckle is attached to each axle and are held in place by a kingpin that is in turn held in place by a tapered pin. There is a D-shaped brass bushing the rest at the top and bottom of each axle. This bushing is sandwiched in between the axle and steering knuckle. Two swing arms are attached to each steering knuckle. The top swing arm acts as the threaded spindle that the wheel mounts to on the outside and the threaded spindle that shock absorber mounts to on the inside. A coil spring fits over the shock into a shock tower that is fastened to the shock at the top and two points on the knuckle at the bottom. The bottom swing arm holds the brake backing plate in place and adds strength to this rather unique assembly. That brake backing plate holds your brake cylinders, brake adjusters, shoes, springs and bearings. The front hubs fit over the spindle and then comes the tire and wheel.
On the back side of the knuckle, there is a oblong cast lobe on the drivers side that points to the inside of the frame and is where the steering arm attaches. There is no lobe on the passenger side. There is another small lobe at the lower rear of each knuckle where the tie rod attaches. The factory tie rod, at least early models, was made with one end fixed and the other threaded although repro tie rods are threaded on both ends.
Start your dismantling procedure by removing those shock towers. You'll need a spring compressor for this. John Jensen's homemade compressor mentioned in his "Restoration" book is perfect for this (works for dismantling that door piston too). This compressor is basically a piece of wood at the bottom with two, threaded rods extending up and conforming to the shape of the shock tower. A piece of aluminum or wood at the top holds everything together. That top piece should have a hole drilled in it so the top shock bolt and nuts can fit through it. Turning each top nut on the compressor down a few turns at a time will compress the coil spring and shock to the point that all stress is relieved on the bottom bolts. Just remove those bolts and un-compress. The shock will come out attached to the tower and can be removed once it's off.
One area that will require a bit of heat and elbow grease the kingpin retaining pin. This pin is tapered and fits tight. We had to heat ours and hammer it out, rendering the old pin useless. This pin comes out to the front, by the way. We ordered two new pins for around $12.00. Another area is the kingpin itself. There is a groove around the bottom of the kingpin that should slightly protrude from the bottom of the knuckle. Heat this whole area up and you may be able to pry it out with a flat blade screw driver. A pair of vice grips, with a little twisting action worked on ours. Bag your pins up and mark which is right and which is left for reassembly.
When viewed from the side, you could say that the Isetta's rear suspension is triangular in shape. The shocks make up one angle, the leaf springs another and the curved frame T-mount that that secure the shocks the third. It's a very simple design and one that is very easy to restore.
The shocks aren't exactly off-the-shelf items but aren't as unique as the front shocks. While exact repro rear shocks are available at outrageous prices (They pay an arm and a leg for them folks. They're not trying to gouge you.) many restorers of microcars have simply gone to their local NAPA auto parts store and bought a pair of Chevy LUV/Isuzu PUP shocks for a fraction of the price. Stand advised that the shock bushings have a steel sleeve in them that is slightly larger than the Isetta's mounting bolt on the lower end. A simple sleeve can be made and pressed in to make them fit perfectly. Just don't expect to take them home and pop 'em in out of the box. Last we heard, you're looking at the difference between $120 EACH for repro shocks from Germany and around $15-$20 for the NAPA units. Other auto parts stores, no doubt, can source these for you as well.
Make sure that you have the proper rubber bushings both above and below the top shock mounting bracket. We got extremely lucky and came across some rubber biscuits that weren't used by a shock and muffler shop. From the side, they had a rectangular profile with a raised center lip on the top and bottom. We just cut one in half and, bingo, they dropped right in. The other one got the same surgical procedure and went to another Isetta owner for his restoration project. And the price was right. These are also available from your parts suppliers for a reasonable amount of cash.
Spring refurb is covered in detail in the "SPRINGS, REAR" section of this page.
Tired of trying to get three ground wires into one of those skinny little holes? Want to run an extra circuit or two but would rather keep them separate from the factory wiring scheme? This is probably no big secret but go to Radio Shack and pick up a couple of replacement blocks with extra connecting points. These are the same type your car came with but with more room. Cheap!
The factory designed the Isetta chassis for bias-ply tires and that's how they rolled off the assembly line. At the time, Metzeler tires were fitted to many Isettas. Over time, the radial, thanks to Michelin, rose to the forefront in the marketplace and many bias ply tires were chucked for the better performing and longer lasting radial brands.
We popped a set of five (four on the ground and a spare) Michelin MX 145R10's on our yellow car. They're great but a bit pricey. Being mounted on split rim wheels (see Wheels section), we also got five new 10" tubes with bent stems to air 'em up. The guys at Coker Tire in Chattanooga, Tennessee supplied the goods. Unfortunately, as of early 2004, these tires are no longer available. As a matter of fact, when we first tried to order them, they were out and had no date for a new shipment. After calling back six months later, we got lucky and were able to grab five tires out of an order of a hundred they had coming in.
So what do you do? Well, Coker still offers the BF Goodrich Silvertown bias-ply tires in either blackwall or whitewall. Our friend, Robert Mace, runs four of the spiffy wide-whites on his green car and they work like a champ. Expect to pay somewhere in the $70.00 range for their 480-10 blackwall and about $10 more for the wide whitewall units. You eagle-eyed readers will note that the tires are even shown with Isetta hubcaps and turbo trim rings!
In April 2004, Isetta enthusiast Ron Leone over in St. Augustine, Florida, posted a great tip on the Isetta Owner's Club of Great Britain announcing that the Tire Rack (finally!) has the Kuhmo 756 radial out there for sale. And how about $27.00 a copy to boot?!? If you're so inclined, head on over to their Web site and do a search on 145/0-10. Here's a shot of the tire and a closeup of the tread pattern. Pretty cool in our opinion and the price is big-time right! You're looking at $175.00 for the five of 'em including Fed Ex econo shipping.
Sure, their are many of you that know of other sources. Trailer tires will probably do the job as well as other brands but it's going to be hard to beat the Kuhmos for all around performance, price and availability ... especially when you have a proven source like the Tire Rack to deal with. If anyone can chime in on another source or brand, please let us know and we'll post it. One thing's for sure though. The price of a new set of quality tires for your Isetta just took a nose dive!
PS: For you split rim folks out there, unless the Tire Rack has them, you'll need to get your bent stem 10" tubes from Coker. Ask for their part number TR-87. They run about $12.00 a copy plus shipping.
Factory tire pressure spex for bias ply tires is 17 psi in the front and 14 psi in the rear. The spare gets 17. For you radial dudes, the rules change and you'll just have to play with these numbers. We run 25 psi all the way around and it makes a huge difference. We've seen several numbers thrown around but this comes with in a few pounds of what various radial owners run. Rule of thumb, drive your car. Your rear end (not the car's, yours) and the feel of the steering wheel will tell you when it's dialed in. Once you're happy with the setup, check that air pressure at least once a month, just like you do in your daily driver ... right?
TOOLS AND SUPPLIES
If you're putting a budget together for your restoration, regardless of the type of vehicle, you'll plan on having the right tools either at hand or available when needed. Nothing makes any job easier than having the right tool for the job. We'll break our list into several parts: Must have, must have available when needed and can farm out to someone who has the specialized tools and experience. We realize that there are those of you who may be handy a some of the latter tasks. If you fit that descripton, feel free to disregard the info. We're betting that many of you may be doing this for the first time. Our goal here is to help save time, trouble and money and do it right the first time.
Must have: You'll want these in your tool chest where you're working on your car.
Metric wrenches (3mm-21mm) (Open end and box end)
Metric sockets (3mm-27mm), extensions and ratchet wrench (3/8" drives are
perfect for the Isetta)
Metric tap and die set (3mm-12mm) (FYI: These will cover 98% of what you're likely
Small and medium crescent wrenches
Flat blade and Phillips screwdrivers
Leather gloves (Buy three or four pairs of cheapos. You'll trash 'em, guaranteed)
Small floor jack (MVP makes a great one for under $20.00)
Jack stands (Get four, they're cheap. MVP and others make these in the $12-15 a
Metric thread guage (You'll use this a LOT, you just don't know it yet)
Rust dissolver (PB Blaster is king here)
WD-40 (General, all around quick lube. Besides, it's un-American to not have a
can or six laying around the joint.)
Plenty of rags
Clean work bench and area
Notepad (Make lots of drawings, diagrams and take notes)
Camera (Take lots of pix from every conceivable angle. At some point in time, you'll end up pulling 'em out to solve a problem.)
John Jensen's "Isetta Restoration" book (Can't imagine an Isetta restoration
Must have available when needed: Tools that can be borrowed, rented, used at a remote site by you or someone else).
Pop rivet gun with aluminum rivets (Get the type with the nipple on the end, not
the flat kind)
Air compressor (Sure makes life a lot easier but not mandatory)
Solvent tank (Ditto)
Blasting cabinet (This one could also fall in the category below. It's a lot cheaper
to do it yourself.)
Specialized tools: These would be for the larger jobs and will probably be farmed out to someone specializing in that area.
Body work tools
Brake lining tools
This includes all of the knit-pickin' parts from the aluminum trim under the side windows to the welting between the body and rear bumper and everything in between. Attention to these details can really set your car apart from the crowd. Take those side window aluminum trim pieces for example. If you'll go to the effort to pull out the Yellow Pages and look under "Metal Finishing" and locate someone in your area that has professional grade polishing equipment, you will be surprised at the finish these folks can produce for you. Custom jewelry makers might be a good place to try as well. These trim pieces polish up like you wouldn't believe! Scratches disappear and the luster is beyond that of chrome. Same procedure works absolute wonders on hubcaps (original or repro), window latches, steering wheel hub, turn signal/hi-lo beam switch housings, wiper motor cover, blower housing, valve covers and (aluminum) mirrors. If you're going for a 100 point factory original finish, you can disregard all items except the aluminum window trim, mirror(s) and hubcaps. Those other parts were painted either an off white or silver or were simply in their virgin state when installed on the car. If you want a knock-down-dead finish, go for it!
Small items that can also make a big difference are things like the rubber weatherstrip between the front bumper and door, edge trim around the circumference of the sunroof and inside window sills. There's also the weatherstripping between the sliding front window and fixed rear window. You can buy all of these items, in their original silver/gray color from Hans or Werner. Another alternative is to go to JC Whitney and order it from them in either black or chrome. Again, not a factory color but sharp on the right color car. Jet on over to www.jcwhitney.com and search for 'trim'. You can also call them at (877) 927-7427.
One other small item is the welting between the rear bumper and body. Factory color is silver/gray. We preferred black so we had the upholstery shop make us 3 feet of it in flat black vinyl. Just notch it so it curves nicely around the rear of the body, mark the holes where they need to be cut, punch 'em out and bolt it on. We got tatooed for big five bux and got exactly what we wanted.
This is discussed in detail under "Electrical".
UPHOLSTERY (Also see "Interior")
There are two basic schools of thought here. One is to go with the factory look. The gray cardboard panels, vinyl seat cover and rubber floor mat can be purchased from one of several suppliers. As spartan as it is, a well-done stock interior is very sharp and becoming to the Isetta and preserves that "$1,000 car look". The second choice is to do it the way you want it.
Here in Central Texas, it can get well over 130 degrees inside a car that's parked in direct sunlight in the summertime. We chose the fabric route rather than vinyl but tried to use a pattern and color that was close to the factory original. Let's take each interior panel and the seat as a separate subject.
As previously mentioned, these panels can be purchased ready-to-go if you plan on using the original trim motif. Several materials have been used in fabricating these panels. The originals were made of a heavy textured cardboard-like material and were gray in color. Some folks have used thin Masonite, poster board and corrugated cardboard. If you tend to do things yourself, check with your local upholstery shop and ask for waterproof panel board. This is a common item that your shop uses all the time. Sheets of this board usually come in a couple of different sizes. One is 4' x 8', the other in the 30" x 60" range. The larger of the two sheets should run you in the $25.00 range.
While the left and right panels share the same overall shape, there are some differences you need to address ... particularly on the driver's (left) side panel. That left panel will require a cutout for both the shift lever and heater hose. You will also need a larger 'notch' at the bottom rear of the panel for the main wiring harness and heater hose to pass through. The passenger (right) side panel may require a notch around the door latch striker plate. We say may because most panels that you see have this notch. Our shop made a panel without one and it fits like a champ. That small dip in the top front of both panels makes room for the rear view mirror nuts to clear. Make sure you don't miss those.
Here are two pix submitted by Bill Waite. One shows the stock interior panels he made for his car. They have been sprayed with a gray vinyl paint to match the original color as close as possible. The other pic shows how the driver's side panel looks and fits installed in the car. As a contrast, here is the same basic panel we had made for our car but with gray cloth fabric and thin foam rubber backing.
Rear Deck Panel
This is a big cumbersome thing that takes some doing to recreate. While most of it lies on a flat surface, the front takes a 90 degree turn downward just behind the seat and is held in place by three sheet metal screws at the top of the firewall. In addition, the curved side pieces that fit up under the window sill lip were glued and stapled together by the factory. Finally, there was a hole just to the right of center where the fuel tap lever emerges from under the car.
Like the side panels, the rear deck unit can be purchased from suppliers. We went with a piece of padded carpet on ours. The holes that the factory drilled for those three sheet metal screws were perfect for installing some snaps so the carpet could be removed and vacuumed easily. Two pieces of carpet were cut and glued to the areas on either side of the car above the deck panel. Finally, a small slit was made just above the hole where the fuel lever exits the rear panel.
Here's where things get a little more interesting. If you have a Standard model (no fresh air grilles) you'll have a much easier go of it than those of you who own Deluxe / Tropical models.
The Standard model has a simple, slightly curved one-piece panel that is held into place by small metal tabs around the perimeter of the door. Once this panel is cut, the only other item you will need to address is map pocket in the middle of the door. This can actually be sewn into the panel board or glued. Those German-made upholstery sewing machines can probably sew a Buick engine block back together!
The Deluxe model gets more complicated due to the presence of a sheet metal air duct that bolts on the inside of the door. The panels start out flat on the outsides, come back to the inside at a right angle on the edges of that duct and then flat across the duct. There is also a rectangular cutout in the center of the air duct where the air vent is mounted, your air conditioner's on/off switch if you will. This was the single largest time-consumer in the whole project. Here's what the interior side of the new panel looks like out prior to being upholstered.
Another item that is unique to the Deluxe door panel is the hole that the air flap lever must exit on the right side. It's a small opening but offers an additional obstacle that has to be dealt with when installing the new panel on the door. If your car has dual wipers, the arm for the passenger side wiper will need to pass through an elliptical opening at the top right of the air duct ... one more job for either you or your upholsterer. Finally, that map pocket will attach to the Deluxe panel just like the Standard panel. It should be centered between the bottom of the air vent and bottom of the door.
Under Seat Panel
Given the fact that this panel is held in place by small clips that fit around the inside legs of the seat frame and were removed by pulling it out from the small indention in the middle of the top, it's no wonder that these pieces didn't last long, probably fatiguing down the middle and eventually cracking in half. These panels, like the others, can be ordered almost ready to install in your car or made up at the time your upholstery is done.
This panel is simple in that it is flat but has some key areas around the perimeter that must be cut properly to fit right. While the repro panels are quite good, there will be at least one modification you'll have to make. We have yet to see one that has the slot cut where the under-seat heater lever emerges. While a friend's template may sound like a good idea, we've seen some slight variations on where the lever exits from one Isetta to the next. Those variations have ranged up to a full inch and can make the difference in getting that slot cut correctly or ruining a good panel.
To achieve success, put your seat in the car with the under-seat heater unit installed. Place the panel in front of the seat where it rests on that lever, Centered between the rear of the wheel wells. Make a mark on either side of the lever and you should be set as far as the width goes. Next, measure up from the floorboard to slightly above the top of the lever to determine how far up the slot should go. That ought to do it.
One other modification you may want to think about is removing a portion of the lower driver's side part of the panel. That would be the part that protrudes outward just below the hand brake cable. Why would you want to do that? So you don't have to remove the panel if you want to pull your seat out. By removing that piece, the left side of the panel isn't held prisoner by that brake cable. Conversely, some folks like to have the panel off in order to get a better grip on the seat though. You be the judge of this one.
The repro panels we've seen (and the one installed in our car) have those curved metal retaining clips riveted on. If you're making your own, you might consider using some Velcro strips to hold it on. Several owners we know have done this and it seems to work like a charm. One final take on fabricating under-seat panels. Robert Mace had a slick panel made up from some 1/8" aluminum stock and painted the color of his car. You can see the panel in this mug shot of Bubba and his car.
Isettas had two basic seat frame designs while the seat back stayed pretty much the same throughout the production run. Early seats used front-to-back running springs that were shaped like a string of S's. There were tied together by edge clips, or wire hooks, that held everything together side-to-side and added strength to the seat bottom. There has been more than one story about two large adults riding in an Isetta and sagging those springs down on to the top of the battery terminals and shorting things out, sometimes to the point of setting the car on fire! The later design, coming along in the late '57 / early '58 production runs, was a major improvement and one that can be spotted very easily. The seat bottom was beefed up with additional spring steel straps and several rows of coil springs were added, not unlike the box springs on your bed.
Being a low serial number '57, our car had the 'fire hazard' design seat. Here are a couple of things that were done to greatly enhance the seat's firmness. First, we replaced all of what was left of the factory edge wire with larger diameter wire. Know what works like a champ here? That wire that's used to suspend acoustic ceiling tiles like the ones in most commercial buildings. Just head over to Home Depot and grab a ten footer for about a buck and cut 'em yourself. It's tedious work but it makes a difference. The real biggie was a tip that our upholstery guy passed on. He put a piece of matching carpet on top of the springs before he put any of the padding down. The difference that it made was amazing. The seat is firm but comfortable with no sagging.
A tip you may find of interest concerns that fire hazard. Several Isetta owners have fastened a piece of neoprene rubber, a piece roughly 12" x 12", on the bottom of the seat springs just above the battery. That way, if the seat bottom touches the battery, there is a non-conductive barrier there to help avoid disaster. Another, probably more obvious, solution to this problem is to select a battery with either recessed or side mounted terminals and navigate around the issue all together. See the "Battery" section for more info on this topic.
VENT & GRILLES, FRESH AIR
If you have a deluxe, or "tropical" model with the two grilles mounted in the door, you have extra work to do. It's not too common to see an original set of grilles. Just guessing here but we'll bet that those four soldered studs that bolts the grilles to the door eventually weakened and fell off. We've seen some cars whose vents are covered with sheet metal or aluminum and others with incredibly tacky fresh air vents from late model cars hacked to size and bolted in. Neither looks very good.
New stainless steel grilles are available from parts suppliers at around $125 for the pair. Watch out for those studs though. One of our grilles was very well made from a soldering perspective, the other had two of the four studs fall off. The studs had to be resoldered at an additional expense. Be careful when you bolt these dudes on and remember that the mesh screen goes behind the door, not behind the grille outside the door.
The inside fresh air vent is a two piece item, one part screwed into the door and the other being a slotted piece of aluminum that slides back and forth in the door-mounted piece. This is your air conditioner On/Off switch. The assembly can be shined up or media blasted. Ours was pretty scratched up when we got it. Minor repairs were made to remove some of the gouges and, after masking off the top and bottom part of the door vent back and small round knob in the sliding piece, both parts were glass bead blasted. Go easy here. That aluminum is very thin and will warp from the heat if you get carried away. Let the pieces cool down if you intend to make more than one pass.
We briefly touched on this topic in the Dynastart section. As mentioned, BMW used both Bosch and Noris (whom Bosch later bought out) as their vendors for the VR. Both units were virtually identical with the exception of two terminal positions that were simply located in a different sequence. If you can still even get the Bosch units, they're special order and in the $550.00 and up range. Hans Rothkegel may have a few on hand. But $550.00! Try this instead. Isetta John Wetzel offers a great replacement made by Nosso, a company that provides third-party manufacturing for Bosch in Argentina. These units are slick and a perfect choice should you need a new regulator. Expect to pay under $200.00. Email John at firstname.lastname@example.org or dial him up at (201) 939-2208. Once he receives your check, he'll have it right out to you.
One last blurb on the Nosso regulator: Terminals 2 and 3 are reversed as compared to the Bosch and the mounting flange is slightly wider than the Bosch so the mounting holes will only line up with one of your threaded mounting points on the floorboard behind the battery, assuming it's still in there. The regulator could be fastened to the floorboard if need be. Also, while the mounting screws should provide a grounding point, you might find it a good idea to make a small ground wire and attach it to your battery/frame ground. If you hook it up correctly and nothing happens, there's a good chance that it's not grounded.
Speaking of hooking it up correctly, the wiring schematic for the Noris unit is right here . The schematic for the Bosch unit is just a click away right here . The Nosso VR comes with the terminal designation on the box.
You can thank John Jensen, not me, for those two schematics by the way.
WEBBING / WELTING
These terms are interchangeably used to describe the material that goes between the top of the frame and underneath side of the floorpan. Make sure you get the 1/8" webbing. You have five body mounting points that are above the top of the frame so be sure to add 1/16" rubber padding here so the floorpan doesn't warp or buckle when you bolt the body down.
The Filling Station, a vintage Chevy parts supplier, has this for you. This material is a thick, woven cotton material much like a seat belt on steroids. It's 1 1/2" wide webbing that's 1/8 inch thick, $2.00 a foot. Ask for part number FS-702. You can give 'em a call at(800) 841-6622. Get 15 feet to be safe. You can also get your webbing from Hampton Coach. This is the same as above except it also has adhesive on the back for quick installation. They get $22.50 for a 20 foot roll, probably the better deal. Part number is B-5000-AS. Contact them at 888.388.8726 or www.hamptoncoach.com.
This is a two parter (no pun intended for you split rim folks). At some point in the 1957 model production run, BMW switched from the two piece split rim wheel to the one-piece, solid/tubeless wheel. Just our opinion, but the one piece wheel is much easier to work with and has far fewer issues to mess with.
Let's start with the split rim unit. There is a deeper inside rim and a shallow outer rim and face. These are bolted together with six 8m bolts. Note that the bolt heads go to the inside of the wheel, the nuts to the outside. Purists will paint the inside part of the rim in a battleship gray while the outer rim is an off white.
Reproduction hub caps can be a real pain on split rims. They aren't stamped out of as thick a guage aluminum as the originals and don't just snap on out of the box unless you're incredibly lucky. The issue here is the three tabs welded to the outer part of the wheel that the caps snap on to. The overall diameter of those tabs tends to be smaller than the inside diameter of the hubcap. The problems to solve here are a.) getting them to fit snuggly and, b.) having them centered on the wheel so it doesn't look like you're twirling aluminum pizzas while crusing down the road.
How do you solve this debacle? First, you can go to your hardware store and buy a foot or so of clear plastic tubing. You'll want the 5/16"ID x 7/16" OD variety. Cut fifteen pieces of this tubing and slide them over those tabs, twelve for the tires on the ground, three for your spare. This will enlarge the "circle" that the hubcaps will fit around and give them a surface to bite. If this isn't enough, grab about three feet of 3M Safe Step. This is the wrinkled rubber stripping with adhesive backing that you see on the leading edge of steps going into office buildings, etc. to keep you from busting your keister on rainy days. Get the 1/2" flavor. Cut it down the middle into 1/4" strips and adhere to the inside of the hubcap edge. Once again, you have closed the proverbial gap between the hubcap and those three tabs and given the cap a firm gripping surface. Finally, if it still needs tweaking, take a small hammer and gently tap those tabs back towards the face of the wheel. That increases the diameter the hubcap will fit around, too. Don't get carried away with that hammer, now.
Last but not least, the split rim wheel takes a special 10" inner tube with a bent valve stem. This stem pokes out of the outer part of the wheel at a right angle. Coker Tire has these for you at about $10.00 a copy and answers to part number TR-87. You can also get your BF Goodrich Silvertown bias ply tires here (480 x 10) or some really neato Michelin MX (145R10) radials while you're at it. Other brands such as Kuhmo and Nankang have been used sucessfully as well and at a substantial savings. Some will suggest that you use a band of rubber around the inside of the wheels to allow for a smooth surface while others insist that a generous supply of talcum power on the inner tube be a good practice. This is good advice on both counts although those inner rubber bands aren't the easiest thing to come up with.
On to the one piece units. Blast, paint/powder coat, mount tire, inflate, balance and roll. Hubcaps pop right on. That's it. See where our opinion came from?
On a final couple of notes, if you order repro hubcaps, make sure to designate which type of wheel you have. We've heard that the split rim caps fit the one piece wheels but not vice versa. We can't verify that from first hand experience. For what it's worth, there is one company in the UK that makes these so they all ultimately come from the same place. Also, the lug nuts are different. The splitters use a nut with a smaller round shank that fits into the wheel lug hole and centers it. The one-piecers use a more traditional tapered lug nut. Whew!
WINDOWS, SEALS AND INSTALLATION
Windshield and Rear Window
Here's another area that you can save some money and maybe help a fellow Isetta owner. The front and rear rubber window seals in an Isetta are pretty generic items. Both are identical in terms of seal type, varying only in length. Oddly enough, ask anyone that is knowledgeable about older auto glass and they'll tell you that the Isetta seals are the same ones used in heavy equipment, tractors, buses, etc.!
One of the top glass distributors in the US is Sommer & Maca. Give them a call at 800.527.5170 and ask for the seal, part number 101-2206 and chrome filler/lock strip, part number 101-2254. These are both 50' rolls and you should be able to score both for around $50.00 plus S&H. If you know another Isetta owner, there will be enough left over to do their car with some left over too! You might also try Binswanger Glass if there's one in your area. They can get it if you can find anyone who really cares. Our local office pretty much blew us off. If your taking your window and old seals out, be sure to salvage a piece of the seal and filler strip for comparison. These same seals and filler strip are available, pre-cut from suppliers too.
Unless you're well versed at installing auto glass and have the special tools required, have a professional install your windshield and rear window for you. Most areas have companies providing on-site installation. Going rate seems to be around $50.00 per window. Don't cut a corner here and regret it! Tell them the kind of seal/glass you've got so you don't get someone who just fell off the turnip truck too. Our man knew all of the tricks to use for installing the "old timey" stuff and made it look simple.
Side Windows, Sliding Window Coupe
Although the length of this text might scare you off, the side window install is a simple one that just requires taking things in proper order and double checking your work before gluing things into place. It's a gratifying project, all in all.
First, we recommend that you attach your window latch striker plates on your car if you've removed them for rechroming. The BMW factory used some very small round headed rivets. We used some flat headed split rivets to fasten ours back on. The flat head goes to the inside and the two split tabs coming out on the outside were both bent out flat to secure the plate. They also lay flat against the window sill so they don't interfere with the window felt. Some folks use small machine screws with success as well although you'll have to trim the inside part of your felt to accomodate the threads and small nut. If you have access to the type of rivets (and gun) that are used to fasten brake linings to shoes, those might be the best choice of the lot.
Next, pop rivet your aluminum side trim onto the car fastening only the three rear holes. Leave those forward holes unsecured for now in the event that you have to pull the trim piece out slightly to get either of your windows in their channel. It's just about guaranteed that you'll have to for the sliding windows. Cover the trim with masking tape to keep from scratching it with the windows when you put them in. Next, install your interior window sill trim. If you're going for the original look, get some of the silver/gray trim and just pop it on. It will be difficult to do this after the rear window is in. Finally, clean your windows. The outside front of the fixed window and the inside rear of the sliding window are somewhat difficult to reach after-the-fact.
Our side window seals and felt channel came from Isetta parts suppliers and fit beautifully. The rear windows are fixed and fit into a double grooved rubber seal. PAY ATTENTION HERE! One groove, the rectangular groove, is for the window and goes to the inside.The outer, or V-shaped, groove is for the locking strip and should be on the outside. Make sure you keep this in mind before you make your first cut. You get a little more seal than you need but be mindful of this before you slice. No need for any kind of glue to secure the seals to the car. Just cut the rear of each seal at two angles, one to match the angle where the two meet and another to compensate for the fact that they angle outwards. This can be done in one cut if you're careful. Using a standard case cutter, mount your blade perpindicular to the handle, like a scraper. Be sure and use a new blade for this! Once your done, you might want to put a little glue on the angled edges you just cut for a good rubber-to-rubber seal at the back in the event that they aren't "perfect".
Put some dishwasing liquid on the top and bottom edges of the rear window glass, slip it over the aluminum side trim you've riveted into place and push to the rear. Wear leather gloves just to be safe!. Those rear side windows should scoot right into place for you. Give it a little final push just to make sure that it's seated in the rear and you're done.
Next, put your sliding window in place by inserting the top of the window up into the upper channel as far back as you can get it and then over the aluminum trim at the bottom so it is sitting inside it's final resting place. As previously mentioned, you'll probably have to move that aluminum trim out a bit for the bottom to clear, particularly at the front half of the window bottom. Now, you can slide the lower felt channel in. Make note that the bottom felt should butt up against the top felt where the top felt comes down in the front. In another words, the bottom felt should rest against the top felt, not the body itself. Be sure to cut your felt a little longer than you think it needs to be. You can really only eyeball this so be safe. You can always make a second cut if you have to make it shorter.
You can now slide your top felt in over the window and tuck it into the metal channel. This piece will be cut at an angle at the bottom so, once again, cut it a little longer than you think it needs to be and refit. Now, you can slide your window back and forth tho make sure that everything is aligned right. That rear rubber seal should stop the window at it's rear-most travel. The locking strip that will be installed in that rear seal will not only spiff it up but will serve as the 'official' stop as well.
Once you've verified that the window felt is right, take both pieces back out and finish riveting that aluminum trim in. We used some glue our glass man gave us to secure the felt strips. Once the glue is applied to the back side of each piece, put the lower felt in first, then the top. Be very careful not to let the glue touch your paint job. Once it's back in, slide the window forward and let it set up. You may have/want to pop rivet the top felt into place (if you have the factory hole drilled for you) for insurance but good weatherstrip glue is serious stuff and you shouldn't have to get out the rivet gun.
One detail might be worth mentioning here. We've seen some felt that bunched up a the top of the window where it curves down. This can make for a sloppy fit for the window at this point in regards to sliding it shut easily. If you experience this, you can take your knife and cut several very slight V-shaped notches where the wrinkles are and eliminate the problem. Just be sure to take a piece of white chalk and mark it. Once again, using a new blade for this procedure alone can make it a snap. Don't glue anything down before you've checked for this possible tweak on your car.
Finally, you may get two thin strips of neoprene rubber for either side of your car. These are shims that are usually included when you order your felt. You may find when sliding your window in place (before anything is glued down) that the window sits a bit low. You can place one strip between the body and felt to raise it up into the top channel a bit. The other piece of rubber, usually narrower, is to place between the aluminum trim and outside of the felt in order to push the window back towards the car a bit. This can assist in keeping the window latch handle from scraping the inside of the body and wearing your paint off. We didn't need either on our car but every Isetta can be a tad bit different in this department.
The icing on the cake here is edge trim. You have a couple of choices. If you doing a factory job, you'll want to order some silver gray edge trim (front edge of fixed window only) and the thin rubber wiper/seal strip that locks into it. This keeps the elements from entering that small area between the two windows. We went to JC Whitney for their black flexible adhesive trim and put it on both the rear of the sliding window and front of the fixed window. Looks sharp and we had enough left over to pass on to another Isetta owner here in Austin to redo his sunroof and inside window sill trim.
The Isetta windshield wiper motor is a Bosch unit that appears to be built like a bowling ball. It has two terminals on the drivers side, one for power (bottom) from the instrument panel and another for ground (top). On many Isettas, the ground is provided by the fact that it bolts to the door but thick paint can prevent that from happening. We made a short ground wire that ran from the ground terminal of the wiper motor to the door and fastened it with a VERY short sheet metal screw. You don't have much room to work with here so watch what you're doing and don't punch a hole in the door.
The single-speed wiper, as heavy duty as it looks, is slow but deliberate .. sorta like the Pope waving at a passing crowd. Our car is a single-wiper model, by the way. We've heard of wiper motors torquing themselves loose trying to drag two wipers across the windshield. Prior to bolting this unit in, we got a neoprene washer to place between the paint on the door and the exterior washer for a good seal and to protect the paint when the nut was tightened down. Make sure you get that nut on good and firm so that motor doesn't watusi itself loose. The cone shaped trim ring that screws onto the threaded part of the shaft was polished and is a knockout ... looks good in contrast with the black washer, chromed wiper arm and yellow paint.
Once you have power to the wiper, let it cycle once to find the end of travel to the passenger side and attach your wiper arm accordingly. The wiper blade needs to lay just above the windshield seal. Crank it down there and hit the power again. You should see it arc around almost to the edge of the windshield on the driver's side and then back down from whence it came.
We got a Bosch Micro Edge 10" wiper blade and cartridge at a local auto parts store that specializes in Euro parts. If it matters, the cartridge is flat black, not aluminum. It's Bosch part number 40710, runs around $8.00 and hooks right on to your wiper arm. We looked at a 12" blade but the cartridge was way too thick and would have been out of proportion to the car. Bosch also offers a universal or cut-your-own blade for around $10.00. You just cut it to length and slide it on to an existing cartridge.
Hah! And you didn't think anything could possibly start with "Z", huh? Just about everyone loves Isettas and Praying Mantises are no exception. Just ask Zognorf.
Actually, one other topic does come to mind here. Only in 1956 did BMW offer a Euro-only model with Z-moulding, the cool lightning streak trim if you will. Here's a good shot of a beautifully restored '56 Bubble that's as good an example as you're likely to run across. Just for fun, here's what it used to look like before the current owner got a hold of it.
Isetta Tech. Live from Austin, Texas. Copyright 2002-2005