DIY Parking Brake Replacement

[Aveman]

Originally Posted by 08-730d

Well well. Looks like things are looking up at the moment. Got it coded today and adjusted the brake shoe tensioner. And now it seems to be fine. It just made sweet sounds (altough i haven´t dared to operate it more than once..).

I did also study the first unit that broke. Nothing looks to be burned, and it ran fine while putting power directly to the motor.
I also used it to measure, and found that the only thing I could have done better with the new one was to adjust the bowden cable screw 3mm further out, than it is (or 1,75 turns of the screw). In total the screw has about 50-55 mm of travel, and 3 mm should not make that big of a difference.
I also studied the bowden cable connection inside the brake disc. It looks to me that the ratio of how much the cable moves vs how much the brake shoes are moved is not in our favour. By that I mean that it looks like the cable has to move a lot more than what we get in brake shoe motion. Therefore I would presume that it would be beneficial for the operation of the park brake system to keep this movement as low as possible, by adjusting the brake shoe tensioner so that the brake shoes almost rub.

I don´t know if that makes sense to you others, but it makes sense to me.

Fingers crossed that it keeps on working..

Great to hear, yeah I've been using mine every time I park and it's been great.

Yes typically with any drum brake setup you want the shoes to be causing the slightest drake on the drum to ensure they can have good response when being actuated. This holds true for regular drum brakes or emergency brakes. Once you get your inspection and you feel comfortable use it on a regular basis, it will likely prolong it's life.

On my old unit the motor was pulling around 2 amps, everything else looked fine, it was only one chip on the old control board that was burnt out. I could connect to it using tool32 and it was still able to be flashed and provide error codes etc but ultimately it was bad. Nothing physically looked burnt but as far as I could tell one part of the board went bad.

So my advise for others attempting this is either get yours rebuilt or buy a remanufactured one, trying to repair your own is pretty pointless.