Antilock brake system

Maintenance/Repairs
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1

I have a 2006 GMC Yukon XL 4WD 1500 with 95,000 miles. When I make left turns, after coming to a stop, the antilock brake system engages, making a groaning-pumping sort of sound in the upper front left area under the hood. (This does not happen every time I turn after stops, but frequently.) My local GMC dealer mechanic believes that there is a faulty wheel bearing, and that a signal is being sent to the antilock brake system to engage. Not sure whether I should believe that or not. The repair would be expensive. Any help would be appreciated.

2

When the front wheel bearings started going bad on my 2000 Blazer, I thought the noise was from the new tires. Have you noticed any new noises from the front end while driving? Does the pitch of the noise (if any) change when the steering wheel is turned off-center (i.e. changing lanes, turns, etc)? If so, it is a sign of bad/failing bearings.

It’s expensive since the entire hub with the ABS sensor has to be changed. It’s going back a while, but I believe the hub was ~500 each from the dealer. My independent mechanic charged 350 per bearing. Consider getting a second opinion from a trusted independent mechanic.

Good luck,

Ed B.

3

Yes, I have been noticing noise front left and wondered if tires were the problem. More than likely it is a bearing. The money is one issue, but stuff never seems to go back together quite the same way. Thanks!

4

If you have noise coming out of a bearing, that bearing will need to be replaced anyway. As for proving the sensor is causing the ABS issue, this is easy to accomplish with a decent scan tool. Just monitor the live data stream and look for anomalies in the speed readings for each speed sensor. If one of them reads erratically, intermittently drops to zero, or does anything like that, that is good evidence the sensor is failing (of course, check the wiring before replacing the hub assembly).

5

Thanks. Turns out that it may/may not be a bearing issue, but a brakes issue. I was hearing metal-on-metal this morning when braking. The GMC mechanic took a closer look this morning. I also have a rear axle-seal leak. Oh boy. I have an appointment Monday morning. I’ll have to be ready with my “big” checkbook. Yippy?!