Brakes have a mind of their own, ABS problem

[MrWizard]

Sure but when driving around town are you speeding? no. Unless your an idiot. I drive pretty damn slow tbh. I rather have no ABS than a malfunctioning abs system.

Many fatal collisions happen at speeds of less than 40mph.



I'd rather walk than drive a malfuntioning car.

Please don't take this as an insult.

[rThor432]

I've seen this problem before. The car had a bad ABS unit. The unit itself was crudded up inside. The fluid had probably never been flushed and there was a bit of rust inside the unit as well. I replaced the unit with another one that I pulled from the boneyard and the problem didnt come back.

Just an idea, dont know if you checked that or not yet.

Good luck!

[FredK]

Yep, I replaced the ABS pump with a known good one. I also swapped computers with a known good one from another 318is.

I took the car for a test drive after having rebuilt the calipers. The car now pulls up square, but the ABS is still pulsing when it shouldn't be.

I will delve into the electrical in a couple weeks and keep this thread updated. I have a full set of ABS sensors that I will swap in and see if that does anything. I already pulled the rear sensors and cleaned them and checked the tone wheels, and everything looked fine. No nicks, no dirt, nothing.

[PhillyG]

I just dunno if I could trust a 22 yearold ABS system.

and wizard would you consider a car without abs a malfunctioning car?

[FredK]

Haha, I changed the pads on a friend's 86es yesterday, and the car brakes better than mine! The ABS still works great.

[FredK]

FIXED!

I went outside an hour ago and took a look at the front brake sensors. I looked at the last three digits on the L and R sensors. They were the same, 982. I knew that the E30 ABS system uses two different sensors up front, so I looked at the ETK. It turns out that the left side sensor is 981 and the right side is 982. So, I had two right hand side sensors installed.

I looked in my pile o' sensors, and found a left side sensor. I installed it and I just got back from a test drive. Works 100%. No more premature wheel lockup, and very even braking all around.

This error must have happened when I just arbitrarily looked in my pile o' sensors and installed two front sensors back when I built my car up last August, without paying attention to the L/R difference in the sensors. The right side sensor has a longer lead length, and the left side sensor has a shorter lead length, and they must pass different signals to the ABS computer. I've been fighting this problem for a long time, and I'm just glad I finally found the source of the problem.

[atomic]

:woowoo:

[1990m3]

wow, congrats on fixing it...that has been lingering for a long time. I have had problems like that on my car that linger forever and it turns out to be something simple and easy -- in your case no cost either!

I've swapped sensors out and back on my car when the suspension was going through a redo and I must have been lucky. I had no idea that sensors were L/R specific. Now I'll think I'll check mine just to be sure it's right...

[PhillyG]

Good job. Great to hear it was something so simple.

[FredK]

Yeah, I already went through most of the braking system eliminating the variables, so it was a relief to find it was something simple.

The L/R sensors look nearly identical. Hopefully they ARE different, and it's not me just swapping sensors out and imagining that I solved the problem. I'll be testing it out and I'll report back in a few weeks.

[Jand3rson]

Time to go check my sensors!

[moatilliatta]

Same! Good find man. I had the front end all apart months ago and have had this problem. Sometimes in the mornings my abs light comes on. This may not fix that. But it may help it to slow the fuck down. I got to look over my wires. I might be getting some condensation on them over night or something to. Good find!!

zach

[StreuB1]

ABS it there to keep your car straight and at optimal slowing in a panic stop situation and was was mandated by the feds to be installed on all cars by the late 80s.

Wrong

There are still cars produced today that are forsale on the USDM that do not have ABS. My 2000 civic si didnt even come with ABS as an option. Its an enthusiasts car and was produced as such....no ABS. Brake lines from master cylinder directly to the calipers homeboy.

[Knockenwelle]

FredK, I'll buy you a beer if I ever see you. Nice catch!!

I got the front end of mine up just now, pulled the wheels, and looked at the sensors. The part number didn't tell me anything, but when I pulled them out, I saw the sharpie FL and FR I had put there when they came off. They were switched!! I had to do this originally to clear strut reinforcement plates I welded on, but I didn't realize that the diamond-shaped magnet was clocked opposite relative to the bolt hole. Makes total sense now, but geez, that one had me. I carefully twisted the pigtail to clear the struts and switched them back to their correct side. ABS works perfectly again, and the pedal is normal. YEESSSS!!

[FredK]

Sweet!