No rear Brakes!

[02stu]

I have been fighting a brake problems for awhile. Yesterday I noticed that I could not get any brake fluid to the rear brakes. There are no kinks in the brake lines and the pedal is hard to push like there is not much boost . The ABS also does not work and the ABS light is on. Any common problems that would explain this? The booster is from a e21 320i.

And yes I am driving the car like this.

[Mike B.]

Has the ABS light been on since you completed the swap, or is it a new occurance? How did you bleed the brakes, pressure bleeder or pedal method?

It sounds like a bad ABS pump unit.

[02stu]

Thanks for you reply. The light has always been on, and I did not pressure bleed the brakes, I used the pedal method. Have you ever heard of an ABS pump going bad? Can I just bypass the pump and run no ABS?


It is also worth noting the car sat for 4 years.

[Hick]

Brake bias/proportioning valve, on driver side frame rail near firewall IIRC. theres also a 'splitter' above the rear subframe where the line to the rear splits into two lines.

[Mike B.]

I asked about the bleeding method because the pedal method creates a higher line pressue and is better about removing any obstructions in the lines.

How is your Pin 20 (Red/Yellow) at the C101 wired? Are you getting power to the ABS pump?

If the ABS pump is faulty. You can bypass the ABS pump, but you will have to run a T-fitting to split the front line to each side.

btw - I have a working pump you can try if it get's to that point. Just send me a PM and we can work something out.

[02stu]

can I just give 12V to that wire?

[SchnellerVert]

Pull the relay and see if the solder connection is broke. You can repair it. The brakes revert to manual with out the abs system working.

[rcko]

ck out the grassroots motorsport website they been chasing a rear brakes issues in their Spec E30 and it appears to be a faulty ABS manifold thing. Their issue is reverse to yours, brakes will not release.... Might be worth reading to give you an idea of what to look for. It is in their project car column of the website

[2002maniac]

here's what you do, start in the rear and work forward until you isolate the problem. Have someone put some pressure on the pedal and loosen the fittings at the calipers and see if you can get any fluid to leak out. If you dont get anything keep moving forward all the way to the MC. You should be able to pinpoint your problem area pretty easily.

good luck.

[e30evolution]

The brake bleeder screw could be clogged very easily