ABS Acting Up (1 Viewer)

[Widenbruck]

Hi. I searched and didn't find info. If anyone can help with my issue or guide me with links to previous discussions it would be much appreciated, since I seem to be stuck...

Vehicle: 1995 80 Series, US spec.

Symptom: ABS dash light intermittently on. Every now and then when I brake normally at a stop, etc. ABS activated in one front wheel (driver's I believe), which causes loss of stability that I have to correct via steering wheel (this happening at high speed would be dangerous). Then it goes away and brakes normally...Next day, similar experience, and so on.
Relevant note: ABS light came on after having a shop do a complete front end job, including wheel bearings, seals, etc. Yes, I know, the ABS sensors are there but they look fine.
All scanners I've used don't show ABS system so I can't pin point if the fault is within a sensor or in the ABS central unit.
I was told to switch both front wheel sensors to see how it reacts.
How would you approach diagnosing this fault? I am at a loss and can't drive it until it gets resolved. I realize I can bypass the whole ABS system, but I'd rather not, if possible.

Thanks for any help!

 

[Kernal]

@Widenbruck: did the symptoms start shortly after the front axle work? If less than 12 months (most shops warranty their work for that long) I would take it back to the shop that did the front axle work.

 

[Mat Jadamec]

I pinched a wire with a wrench on the front without realizing it, doing similar work on my '94. It took a while for it to fail (conductor) and there were intermittent ABS lights while this was going on. I was not sure there was a problem until it was always on. On the '94 there is a ABS diagnosis procedure in the FSM separate from the engine diagnostics that identifies where the fault is. It worked and I was able to find the faulty section and replace it.

 

[ajax1]

Pull the sensors out of the front knuckle make sure clean, look down hole see tone ring is there, should be if you didn’t swap birfs. Look over wires, pretty easy system

 

[Kernal]

"Every now and then when I brake normally at a stop, etc. ABS activated in one front wheel---"

@Widenbruck : might help to check that the brake calipers were installed properly (loose or missing mounting bolts, correct pads, etc). Also check that the wheel bearings aren't loose (preload).

Were any major parts replaced?

 

[Widenbruck]

Thanks everyone, will follow all advice given. Appreciated.

 

[Widenbruck]

I pinched a wire with a wrench on the front without realizing it, doing similar work on my '94. It took a while for it to fail (conductor) and there were intermittent ABS lights while this was going on. I was not sure there was a problem until it was always on. On the '94 there is a ABS diagnosis procedure in the FSM separate from the engine diagnostics that identifies where the fault is. It worked and I was able to find the faulty section and replace it.

I will check the procedure, thanks!

 

[Widenbruck]

"Every now and then when I brake normally at a stop, etc. ABS activated in one front wheel---"

@Widenbruck : might help to check that the brake calipers were installed properly (loose or missing mounting bolts, correct pads, etc). Also check that the wheel bearings aren't loose (preload).

Were any major parts replaced?

Bearings and knuckle seals/gaskets.

 

[TomH]

The first thing to do is follow the procedure in the FSM to determine which wheel is the problem. Once you know that you can work to resolve the problem.

When I had a similar issue, it turned out to be a loose wheel bearing in the rear. Adjusted the bearing and the problem went away.

 

[ajordan1975]

Delete the ABS.

 

[Widenbruck]

Delete the ABS.

Easy way out, not there yet.

Will diagnose following FSM's ABS chapter procedure and report back. Thanks again.

 

[ajordan1975]

Easy way out, not there yet.

Will diagnose following FSM's ABS chapter procedure and report back. Thanks again.

Best way out in my opinion

 

[joxeale]

Best way out in my opinion

Only way out in my opinion

 

[Widenbruck]

Only way out in my opinion

I so see the value of one less thing potentially failing when you are out in the trails. Definitely an option, but would like to understand and fix the issue first.

 

[Kernal]

@Widenbruck : How long after the front axle service did the symptoms start?

Have you determined that the front axle components were reassembled correctly??

Have you taken your 80 back to the shop that performed the front axle service?

 

[ZetheGSD]

I so see the value of one less thing potentially failing when you are out in the trails. Definitely an option, but would like to understand and fix the issue first.

I can totally agree with learning more about your 80 and checking over all system to make sure of the failure. But just in case you find issues with the wiring or unit itself, the delete route also makes your brakes feel much stronger and controllable.