So ... brakes

6716

Original poster
Member
Jul 24, 2012
821
First issue is that ABS fires every time I am coming to a complete stop. The interwebs seem to think it is the sensor. I cleaned it up but I think the reluctor is dirty as well. I might just change the hub and see what that does.

Recently the ABS light has been coming on intermittently.

There's also the sort of groaning squeak when I push the pedal. I read that might be the booster.

I'm wondering what I will learn about the master cylinder when I pull the booster.
 
Dec 5, 2011
574
Central Pennsylvania
Hubs.... do both.
ABS controller uses "tone" from the sensors to gauge wheel slippage. It compares all the "tones" to do so. A dirty reluctor, a pinched wire, a dirty pickup, etc, all these can negatively affect the "tone". Cleaning is a good troubleshooting step - did you do both sides? I can't remember if the reluctor is sealed or not, perhaps a blast or two with electrical cleaner will improve it? Is there rust on the sensor mounting surface? I had to clean mine up with a precision file to remove paint and rust. Your intermittent ABS light could be sign that you need to replace/repair more than one sensor - the gold standard for that fix is to replace both front hubs. This may not be economically viable for you, but it is fairly straightforward and doesn't have to be crazy expensive - rockauto is your friend here.
My brake pedal has groaned/squeaked from the first day I owned the vehicle - 175k miles later, it still does. Are you leaking any fluid? Is your pedal too firm or spongy? If no to both, I wouldn't pull the MC or booster - just my humble opinion. Pulling the MC may result in the invention of several new curse words and will require a complete flush of the entire brake system (including ABS pump) to get rid of air.... I don't loosen MC lines unless I have absolutely no other choice.
 
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TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,045
Brighton, CO
Had this same problem with my Envoy when I bought it. New wheel bearings (They come with new ABS stuff), problem went away.
 
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6716

Original poster
Member
Jul 24, 2012
821
Is there rust on the sensor mounting surface?
LOL. I'm up north. There is rust EVERYWHERE.

I did not clean both sides. The ABS has pulsed for longer than I would like to admit and I always attributed it to getting grease on the ABS sensor when I put on the driver's side new hub. When I look down the hole for that sensor, it looks like the center of the reluctor is dirty as well -- at least in comparison to the outer parts.

A pair of new hubs wouldn't kill me -- throwing parts at this vehicle is still cheaper than pulling the trigger on a newer one.

I feel like it has been getting worse ... but that is entirely subjective. Maybe one thing at a time, ABS first and pedal squeak second.
 
Dec 5, 2011
574
Central Pennsylvania
Been there, done that. Don't do what I did. I pulled the ABS fuse in the misguided idea that I'll just drive it that way to get through "summer" and put a new set of hubs on in the fall. 2 weeks after pulling the fuse I locked up all four wheels in a panic stop as there was a literal pile-up in front of me. I managed to stop in time. So did the guy behind me - but not without getting 2 cups of coffee covering the inside of his windshield... lol. I put hubs in the next day and replaced the fuse. Never again.
 
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Eric04

Member
Dec 3, 2014
392
West Michigan
Dropping 2 cents in the bucket for the replace the hub strategy. I've had this once, ABS firing at complete stops, ABS light. I forget the related code but it pointed to the sensor on passenger side. Replaced the hub and all quiet since.
 
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Mektek

Member
May 2, 2017
656
FL
I keep the sensors from old hubs in case of a sensor problem. OBD diagnostic will usually tell you which sensor is bad. Or you can check the impedance - if open circuit the sensor is bad.
The sensor operates in a grease filled hub - if there's some grease on it that's OK.
 

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