ABS plus strange grinding noise

Robert Jacklin · 06-08-06, 01:47 AM

Long story.

For about the last year I've had a brake thing going on.
I would get this "pinging" noise that sounded right in front of me and a brake peddle shimmy, only when I'm going very slow. Brakes seem to act normal.This would happen pretty regularly. Thought maybe ABS.

Checked check valve to brake vacuum reseviour just in case.

Had it checked at dealer and said couldn't find problem. After a while it went away.
A couple months later did it again for couple months. Dealer worked on rear brakes to tune of $400 but didn't make any difference. After a few more weeks went away.

It was starting to do it again occasionally. I went to drive out of my garage and heard a electric motor sound coming from under the hood? I shut off engine and the electric motor sound was still there!!!

Popped hood and discovered sound was coming from ABS unit. Pulled battery cable to stop the damn thing while I tried to figure it out. I eventually found the fuse under the hood that allowed me to isolate the motor.

Since I 've disabled the ABS the funny pinging and brake foot shimmy has disappeared. Looks like it origin was the ABS. Do the wheel sensors sometimes go bad and cause this? Other ideas?

Within a day or so of the ABs acting up I started to hear a high pitched scraping/whining noise coming from my right rear wheel area. Happens at very low speed, backing from parking space, pulling away from light. More pronounced when I make a slow left turn. Definitely relates to rate of wheel rotation. Does not go away with light touch of brake but will with heavier application. Happens going forward and backing up.

I figure the ABS acting up and this noise could be related.

Looked at wheel assembly carefully. Lots of brake pad left. No looseness to wheel bearing. No obvious dirt in between pads and disk. Rotates easy with no unusual noise. ABS sensor secure. No signs of rubbing on splash guard, wheel well. No oil leaks. Hand brake releases fine.

Everything looks great.

I hope it's not differential. Sound has a very clear high pitch that I would not expect to come from the differential at barely walking speed.

I'm looking for suggestions on what is going on.

Thanks
Bob