The next project has arrived! 1990 535i automatic.

Today’s fun was running down south to pick up a pretty decent 1990 535i. This particular model is an E34 chassis, outfitted with the 3.5 liter M30 motor and a 4-speed automatic. Paint is the common “Bronzit beige metallic”, paired with “Natur” leather upholstery. The build sheet also turned up a few very nice options. The limited-slip differential was a pricey option, fairly rare on the automatics. Heated comfort seats were also installed, but are unlikely to be working. Unusually, the seatbacks are not twisted (it’s an all-too-common problem with these seats).

The previous owner had been very good to the car, upgrading the suspension with Bilstein B8 Sport shocks and Eibach lowering springs. It also came with an excellent assortment of spare parts, including a genuine set of forged Style 37 “M-Parallel” wheels. These were fitted to many later BMWs, including the E38 7-series and the E39 5-series.

The car is in excellent mechanical shape, especially considering its age. There isn’t much in the way of rust. The car runs, and even left the seller’s driveway under its own power. I’m told the r134 conversion still works. HVAC system appeared functional. No missing pixels! The hood is a newer replacement, but it’s a pretty decent job and appears to be the only new panel on the car. The paint is still in decent overall shape too. There are a few cosmetic issues inside: the door panels are complete, but all de-laminating, roof liner has fallen off, sunroof inner panel was removed, minor cracking in the front seat leather finish, etc..

It has a long list of problems, but we’ll be working through them as time permits. The biggest problem is the water pump bolts. They’ve all practically welded themselves into the block. It stumped the previous owner, I’ll see what can be done. If I had a welder, I’d tack a 10mm bolt onto what’s left of each pump bolt and spin them out.

Battery wasn’t a pretty picture, very close to totally dead. I measured 1.6VDC. My little jump pack still managed to start it several times (briefly, of course). That came in tremendously handy for loading it onto the flatbed. When I pulled the terminals off I noted some significant corrosion on the positive cable stud. Lots of metal had been eaten away, appears to have been a slow acid leak. That’ll need replaced!

The car is running quite roughly, I suspect that primarily due to it sitting idle for two years. I’ll clean off the crank sensor too, those always get gunked up.

The driver’s rear door doesn’t open. Seems to me that the lock actuator is jammed shut, permanently locking the door.

Something is very loose in the front end, I’ll lift that up and take a look eventually.

April 6, 2021: I’ve been steadily working on the car. Lots of little problems have turned up, but only two big problems remain. The water pump bolts fought the good fight, but they’ve been drilled out. I’ll reassemble the water pump once the replacement radiator gets here. Why replace the radiator? Well, the transmission cooler failed, flooding the unfortunate ZF with a bit of coolant. I’m unsure if it can be saved. I’ll dump some cheap ATF into it and see what it does. The old 4HP22 wasn’t a bad gearbox, it might last a little while longer. I was planning on a manual swap eventually, so this just bumped up the clock on finding those parts.

I even completed the tool kit – all it needed a pair of slip-joint pliers and the towing eye!

April 19: Rear door is fixed. Mistakes were made, door panel was somewhat inconvenienced, but the latch is fixed! If you’re really interested, it went a little like this:

  1. Lower rear door window, unscrew locking pin.
  2. There are three concealed screws in the upper door: remove ash tray, black plastic cap behind the door release, and door handle plug to get at them. Carefully pry the upper door panel away from the chrome trim, trying not to crack the thin paperboard door panel. In my case, the black upper door trim came off the panel, making this job a lot easier.
  3. Carefully reach inside, unhook the door release cable and power window switch.
  4. If possible, get a long thin steel bar and begin to pry the door clips away from the perimeter of the door panel. Work your way down both sides, then try the bottom clips (I couldn’t do this step, I decided to break the panel a little and directly work on the lock). However, most of my door clips and/or door mountings were already broken. The E34 door panels delaminate significantly as the adhesives all break down over time. That’s the price of less-toxic chemicals used in car production; a worthwhile trade-off in my book. Repairs are easily done with craft paper and furniture-grade (water-resistant) wood glues.
  5. Finally, lift the door panel straight up. The door handle grip is retained by a plastic slider fitting; it can only be released by sliding it up vertically. In my case, the door panel will literally dissolve in a puff of wood pulp.
  6. There is an inner foam insulator membrane, slowly peel it away from the door frame. Be careful not to touch the black mastic/goo (butyl adhesive) onto any trim, it will stain. In my case, it blew off the top of the car and picked up all sorts of leaf litter from the driveway and lawn.

Now that I was looking at the inner door, the rest was easy!

Not really, that’s an BMW ‘inside’ joke. The struggle was only beginning… The real problem with a stuck lock is almost always the actuator. They tend to rust internally and then refuse to work. BMW’s supplier carefully designed the actuator case to be waterproof. It’s glued shut, thus nearly impossible to repair. The lock actuator rod is has a rubber bellows that fails over time. BMW chose to mount the actuator with the bellows pointing up, directly under the window seal, designed to catch and hold water, with no way to manually bypass the power function. Frankly, it’s engineering perfection!

Pro tip: The early bolt-in actuators are now worth more than the rest of the car. Throw them away, convert the car to manual locks. The later actuators are reasonable from what I’ve seen.

Here’s how to remove the early actuators:

  1. You’ll see the actuator body and lock lever towards the rear upper corner of the door.
  2. You can clip or break the plastic actuator catch, but I bent the lock actuator lever slightly, far enough to unhook the actuator.
  3. Then I was able to manually unlock the latch, and the door handle might FINALLY work! Or in my case, the inner door handle cable will pull out of the latch assembly, and jam the outer handle.
  4. I managed to open the door with a long screwdriver. I pressed the door release lever inside the latch assembly. The door opened!
  5. I then removed what’s left of the door panel but didn’t close the door. Just to be 100% sure it worked, I tested the latch while I had the door wide open. Unsurprisingly, it wasn’t working. It would latch, but neither door release was working.

Pro tip: Before you close the door to test that latch. use a screwdriver to close the door latch. Be sure the inner and outer door releases are functional. In this case, both were non-operational. I had bent the lock lever slightly to remove the actuator, and it wasn’t properly engaged with the remaining parts of the latch receiver. Thus, the latch was permanently locked. I removed the latch receiver’s three (T20?) torx bolts (one is hidden under the weather stripping), then carefully bent the locking lever detent pin back into shape, verified that the child lock wasn’t engaged, and the assembly started working again!

So it’s all back together, door is working well. I did some pretty significant damage to the door panel, but it wasn’t in great shape to start with. As the saying goes: “You can’t make an omelette without breaking some eggs.”

The next chore is drilling out the water pump bolts. I’m sure it’ll be epic.