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Discussion Starter #1 (Edited)
The truck, for a year or so now, has had the issue where when coming to a stop it would pull left and I could feel the ABS through the brake pedal. It would do this on bone dry roads. It was bad enough that it felt like someone was removing 30-50% of the braking power of the truck.

So, until I could remedy it, which was just now, or so I thought, I pulled the 60A ABS fuse under the hood.

With doing other maintenance to the truck that included:

New Rear axle seals (both)
New Rear brake pads
New Rear rotors
New parking brakes (factory shoes soaked with gear oil)
New front rotors
New front pads


I also installed a new right front ABS sensor. The old one didn't look bad, and again I suspected it was the right front because the truck pulled left, which would make sense if the right front was releasing.

So anyhow, that didn't fix it. Exhibited the same conditions as prior fix. I then ordered a complete new hub, and noticed when installing it TODAY that they had shimmed their brake sensor, which was included with the new hub. The old hubs appeared factory, and have around 163k miles on them.

After installing, I could barely feel the ABS kicking in when stopping, then the issue stopped, and viola, the ABS light came on intermittently and then finally stayed on. Checked the Edge Insight, and there's no codes thrown.

My next step is to install a new left front hub and ABS sensor. Until then, the ABS fuse will come back out.

Any thoughts or ideas on this issue? Could both front ABS sensors have failed?
 

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...Checked the Edge Insight, and there's no codes thrown...
Will an Edge Insight pull up ABS codes? Reason I ask is a while back in this Emergency\9-1-1 thread fellow member IGO1320 had a CEL and his Edge CTS had nothing.
http://www.dieselplace.com/forum/76-speciality-forums/125-drivetrain-2001-2010/764169-possible-front-hub.html
He finally found someone with a Tech II that could read the DTC's and sure enough it was a bad hub - though it was still quiet and tight as a tick.
 

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The front ABS sensor out of range issue typically doesnt throw a code. The problem is that the sensor gets pushed up slightly by the rust and cant read the teeth on the ring at slow speeds, the computer then thinks that wheel is locked up and then dumps the brake pressure to that wheel. There is a simple way to test the sensor and they can sometimes be removed and the mount surface cleaned to bring the sensor back within spec. GM did the remove and clean on the ones that NHTSA forced them to recall.https://www.youtube.com/watch?v=Ld5-eoYGAiA
 

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This is a common and well-known problem on the HD trucks. Rust builds up under where the sensor seats on the unit bearing, pushing it away from the reluctor wheel inside the hub.

Replacing the hubs is certainly a solution, but it should be as simple as pulling the abs sensor and cleaning the rust off the seat. My 3500 was doing it when I bought it 5 years ago. I pulled the 60A fuse and haven't looked back. I wear the ABS and brake warning lights like a badge of honor.
 

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That sensor being raised from rust is common and does cause the brakes to feel like they've released, at slow speeds almost at full stop. But it won't cause the light to come on, at least mine didn't. I cleaned mine and reinstalled but it didn't take long to occur again. I replaced both hubs with timkens. If those are factory hubs at 163k replace the other. You've gotten far more than most out of that. Check and clean the ground on the frame rail below the drivers door aft of wheel well. It's a common cause of the abs light on and abs pump running .
 

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...That sensor being raised from rust is common...
That's what I hear - just that it's something we never get to see here in the land of perpetual sunshine (thankfully). As soon as the skies darken with the impending first snow up north IGO1320 quits delivering trailers and high-tails it home to central Florida until the spring thaw (something about tire chains and his aluminum PYOs I think). Anyway, the ABS sensor's seat on that bad hub was as bright and shiny as a new dime, but yeah, if I lived in road salt country I would first check for rust.
 

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Flushing the brake fluid and greasing the caliper slides are two parts of keeping your brakes maintained. You still have fluid trapped in the ABS controller (I rarely read about the controller going out) so one would suspect some moisture in the ABS controller corroding/sticking some of the valves, after all these trucks are aging and new problems are arising everyday.

I finished installing new flexible lines over the weekend and had a friend come over with his Chinese TECH-II and cycle the ABS brake module several times and bled the brake lines again afterwards. The pedal did come up a bit and is not as sensitive, may be combination of both items being done. The ABS cycling was in the powertrain section of the TECH-II and my transmission shifts a whole lot different, could be in my head but doubt it....

It may just be you have to activate the ABS controller the redneck way, 5-6 times from 40-45 mph on a dirt road to a stop should do the trick and then bleed the brakes...
 

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Discussion Starter #8
That sensor being raised from rust is common and does cause the brakes to feel like they've released, at slow speeds almost at full stop. But it won't cause the light to come on, at least mine didn't. I cleaned mine and reinstalled but it didn't take long to occur again. I replaced both hubs with timkens. If those are factory hubs at 163k replace the other. You've gotten far more than most out of that. Check and clean the ground on the frame rail below the drivers door aft of wheel well. It's a common cause of the abs light on and abs pump running .
Thank you for that tip. I will check that when I replace the other hub next week. Waiting for that part to arrive. None in stock with Amazon Prime and have to wait for the slow boat.
 
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