Jury rigging, E30 style.

As noted previously, I’ve posted the little sedan up for sale. Looking for another enthusiast to continue the journey. I’m not sure how long this sales process will take, so I’m adding a few hacks to keep the car on the road.

First off, the rear brake lines are really gone. I’ve decided to plug them with some locally available parts, a solution commonly known as “jury rigging“. Some will also say it’s ‘Jerry Built’ or ‘Jerry Rigged’ but I feel those terms are incorrect. It’s all a throwback to my old sailing days. Less generously, you could also call this a “hack”.

So where do I make the plug, and how do I hold the pressure?

I’ve decided to plug the line at the ABS block. So what do all those letters cast into the ABS brake housing stand for? Which one is the rear brake output? Here’s the answer:

First, know some German, well a tiny bit anyway!

English to German

Front = Vorderseite
Rear = Heck
Right = Recht
Left = Links

So the ABS Pump is Labeled

VR = Front Right
VL = Front Left
HR = Rear Right
HL = Rear Left
V = Front Input
H = Rear Input

And the Master Cylinder is Labeled

V = Front Input
H = Rear Input


Armed with this secret magic, I went off to my local auto parts store. At first I had zero luck. Most parts are still SAE, even today. A parts guy offered to help, but I had some difficulty explaining my conundrum. I’ve never been that great at explaining stuff, but I also suspect that I’m one of the few idiots that actually attempts stuff like this. It felt a little like describing swimming to a desert nomad. Eventually, I found what I was looking for…a metric to SAE converter. This part adapted a 10×1 mm bubble to 3/8″ SAE flare. Triumphantly, I marched up to the counter with my parts, fetched a well-used gift card, paid the cashier a compliment, and left.

The rest was pretty humdrum. After installing the plug into the adapter, I removed the left rear headlight trim panel to make a little space. Identified the target (on the E30, it’s the port on top, labeled “h”, pointing forward, just behind the headlight rear trim cover), then removed the rear line with like a thousand 1/8 turns of my trusty 11mm flare wrench. Working quickly, I swapped the adapter & plug assembly into the open port and tightened it up with a 12mm deep well socket (of course it’s not an 11mm, what sense would that make?). I cleaned up the few drops of spilled brake fluid with a hose, then tested the brakes. That traditional BMW firm brake pedal is finally restored! To finish it up I taped a plastic plug onto the rear brake line and bent it ever-so-slightly out of the way. If you’re attempting this repair at home, be sure you get the correct matching type of tapered fitting, and properly tighten it. Brass into aluminum doesn’t require much torque. I don’t know the exact number, but only a few inch-pounds will seal it properly.

So, with that big job out of the way, I started in on a few other quick problems. First off: figuring out the non-retracting sunroof. It sounded like a gear had stripped inside the ‘roof actuator. I was barely able to close it even with the emergency tool. So I popped off the visors and dropped the headliner trim as far as possible (the headliner covering is also retained by a trim strip under the sunroof panel that’s inaccessible with the roof closed). I removed the gearbox and discovered that the gear was in perfect shape (!). The gearbox operated nicely when I bench-tested it although the motor got fairly warm on the commutator end. I’m sure the motor was overloaded from the last time I ’emergency’ closed it, and I’m suspecting there’s a worn plastic spur gear inside there. The metal worm gears typically strip these nylon spurs if the ‘roof isn’t adjusted “just so”. I had a spare Webasto gearbox on hand from a recently departed E24, swapped it into the E30. Problem resolved!

My final minor job of the day was cutting a trunk trim panel to fit the ski bag mounted in my rear seat back. I’d installed the ski pass years ago but never finished up the rear trim. So after about ten test fittings and some careful cutting (with a “TV Knife”, razor knife and a large cutting board) it’s all good. Not perfect, but I’m very satisfied. Who really checks out a trim panel that closely anyhow?

So how does a BMW handle without rear brakes? If I had to guess, I’d say that rear brakes aren’t necessarily necessary. One could consider them a luxury item, if one was desperate enough.