Brakes have a mind of their own, ABS problem

[whirhalswi]

I was balancing my wheels today an noticed some part of my strut housing around my upper part of my sway bar links running against my unibody. its worn threw they rubberized layer. Just curious if anybody has experienced this.

It looks like it just may be the stud and bolt part of the links rubbing.

[Brew]

What should a good/bad hub look like on an oscilloscope?

If it was filled up with rust I'd imagine you would have a dirty/inconsistent waveform. I've had hubs on customer cars that cracked and produced a longer than normal wavelength once per revolution that threw off the ABS.

[dubdub]

Back from the dead thread...

This sort of problem, an intermittent ABS engagement just started on my IX. I cleaned the hubs, and it seemed to solve the problem, but would like to be a little more confident than that.

What should a good/bad hub look like on an oscilloscope?

Janderson, you ever solve your issue? I had no work in the area to make the change occur either.

[FredK]

Yeah, the best way to test sensors would be to use an oscilloscope. It doesn't even have to be a fancy or expensive scope to get the job done. You should be able to get a used scope for around $100 for a bare bones unit off Ebay.

[Brew]

FWIW, the best way to diag an ABS system is to use an oscilloscope and look at the signal coming from each corner. I've used this method many times at work to find bad sensors and hub rings.

[FredK]

I guess sensors can go bad over time. I had one go bad on my E36 and I never touched it. You can try cleaning the sensors, as sometimes they collect metal filings which can affect signal quality. At the same time you should check the wire insulation. Over time the rubber gets crispy and starts to crack and peel away. The least expensive way to see if the sensors are the problem is to get a known-good set for around $60-80 for all 4.

[Jand3rson]

That's what's different between your issue and mine, I've never touched my sensors.

[FredK]

My issue was completely self-inflicted, because the brakes worked fine prior to refreshing the suspension. After I installed the wrong sensor, that's when things went south. Upon installing the right sensor, my braking was fine.

[Jand3rson]

Fred, did your ABS system just start doing this one day all of a sudden? Mine was fine from the time I got the car, just until I started having the issue around last summer. I haven't checked my sensors yet, and I can't think of why it would start doing it out of the blue, but it's worth checking.

[Knockenwelle]

Do I smell a sticky for ABS issues?

[FredK]

Sweet!

[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!!

[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.

[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

[Jand3rson]

Time to go check my sensors!