ABS not working, but no ABS light

[GotCone?]

First Shakedown event was this past weekend. Went out to an autocross after months of restoration and prep work on this E30. It still needs a some work and some sorting out, but is 90% there. Will be addressing swaybars (currently none are attached), and getting the exhaust done up.

In testing I found that the ABS doesn't appear to be working!!! It was quite easy to lock up the brakes. The tires are 3 year old beaten Hankook RS2's so their lack of grip (they are quite hard) should have made the abs prevalent frequently.


*worst example of lock-up from the weekend.

I'm looking for insight on testing the abs pump or what I can do to diagnose this issue. It wasn't excessive like in the above picture, but it was an issue. I couldn't attack like I normally would in ABS equipped cars. I'm hopeful that I can resolve this as I'd like the car to have ABS.

All brake calipers and rotors were replaced, stainless brake lines were installed in place of the rubber lines, and Axxis Ultimate brake pads were put on all four corners.

I did some searching on here, but most threads were about the ABS light being on (which it isn't) and the relay under the dash or other culprit that would throw an ABS light.

All input greatly appreciated.

Thanks - Jon

[AndrewBird]

The light might be on, but the bulb may be burned out or missing.

I'd start be checking the wheel sensors for dirt or other stuff stuck to them. I would also check the relay you were talking about. Basically just try anything you can find.

Generally, the pumps don't really go bad, but they can. All I'm saying is, check everything first before you dive into an expensive part.

[DMF]

Hmm. Interesting that it could just be the wheel sensors are dirty.

I bought my 87 325is with the ABS "not working". The light would turn on a few minutes after driving around, usually after a hard stop which I could feel the ABS getting confused through the pedal.

But after a few long drives (4hrs+) through in the rain, the ABS light seems to stay off and I haven't felt that odd feeling in the pedal. I'm skeptical to think that the ABS is competely working again, but if the sensors are prone to getting dirty I guess they might have just gotten cleaned off in the rain?

[GotCone?]

I cleaned all the wheel sensors before re-installing them on the car. I had them out as I had dropped the rear subframe and remove the front strut/knuckles as well.

It is my understanding from the bently that both the wheel sensors & relay/fuse should throw an ABS warning light. I can check that the bulb may be burnt out I guess... but all others work.

Anyone have info or write ups for testing the pump itself... or even the wheel sensors?

Thanks - Jon

[jlevie]

Does the ABS light come on when you turn the key and go out when you start the car? If that doesn't happen the bulb is burned out or the ABS module is dead.