2001 Tahoe ABS ?

[cjac]

Hi all,

2001 Tahoe 5.3L V8; the ABS kicks in every time I brake, leading to an extra few feet of braking distance, and its worse when turning and braking into a parking spot.

I've been told its the wheel hubs, either the bearings and/or ABS sensor, does that sound correct? ABS warning light is NOT on, but the problem is consistent. Had it jacked up, and I don't feel "play" in the wheel if I try to move it.

Q1: If the above is correct, should I replace both front hubs? My understanding is they're a sealed unit and I cannot replace just a sensor or bearings.

Q2: Should I turn both front rotors and replace pads, as the "pulsing" likely is causing warping of the rotors and uneven pad wear?

Q3: Should I also redo the rear brakes as long as I'm this far vested? Assuming pad measurements show equal wear?

Thanks for any advice, Chris

[cjac]

I forgot to add, 135k miles.

[BoxMN]

Hey cjac, I think this is the same thing my 98 k1500 is doing. You can try cleaning it, as I did before, and it should get you some additional miles. I have 190k and I am just going to replace the bearings/hubs at $155 (US made, not chinese) each, and do it myself. To get them "cleaned" as per GM instructions, it will run about $100 or so. For me, the additonal cost of having new bearings is worth them being new and having this behind me.

It is a freaky feeling, isn't it? My buddy almost drove through a garage door due it, haha! He didn't know it was doing it, ha!

edit - if I was you, and those current pads and rotors are still original (with that age GM, they probably are) I would just get new rotors and pads and slap them in, and then not worry about it for another 100k plus miles.

I haven't done the hubs yet, but if you want to do brakes and don't do it yuorself, bring the truck over and we can watch my brother do your brakes and heckle him all the while having a barley pop email me if you want more info.

[Archerysniper]

Mine did the same thing,almost crashed a few times pulling into a parking spot and it would kick in. Mine was the wheel bearing changed it and problem solved.Till you can find the problem you can pull the ABS fuse under the hood which will shut it down so you don't crash.

[Jeremy airjer W]

Q1: If the above is correct, should I replace both front hubs? My understanding is they're a sealed unit and I cannot replace just a sensor or bearings.

I would start by cleaning the sesor mating surface to the hub. This can be done by removeing the caliper and rotor. Be carefull when removing the sensor from the hub. If you break it off you will be replacing the bub. It would be in your best interest to identify the sesnor that is dropping out first. Then try cleaning that sensor. That way if you break it you won't be replacing the one that isn't broke to begine with. This can be done with a scan tool or some do it with a muti meter. You can buy just the sensor. The new bearing will come as a hub/bearing/sensor assembly.

Q2: Should I turn both front rotors and replace pads, as the "pulsing" likely is causing warping of the rotors and uneven pad wear?

Warped rotors and overactive ABS are two different problems. You will feel and hear the ABS kick in during a slow stop. Warped rotors are usually felt during higher speeds when the brakes are applied and you will not hear the ABS motor humming when the rotors are warped. Warped rotors will not cause the ABS to become over active during slow stops. This is typically caused by a drop out of one of the sensors signals which fools the ABS into thinking that wheel has locked up.

Q3: Should I also redo the rear brakes as long as I'm this far vested? Assuming pad measurements show equal wear?

If it ain't broke don't fix it.

[PierBridge]

"Q1: If the above is correct, should I replace both front hubs? My understanding is they're a sealed unit and I cannot replace just a sensor or bearings."

Correct.

Find somebody with a scanner and locate which sensor is lagging or acting erratically. I'll bet on the drivers side front hub/bearing/sensor.

[Macgyver55]

"Q1: If the above is correct, should I replace both front hubs? My understanding is they're a sealed unit and I cannot replace just a sensor or bearings."

Correct.

No, the front wheel speed sensors are a common issue, and can easily be serviced or replaced separately.

Replacing a good hub and bearing assembly to simply cure the ABS problem is needless overkill.

If the bearing is noisy or loose, that is another story, but removing the sensor and cleaning the mating surfaces will, in most cases be all that is needed to alleviate the problem.

[1968]

Agreed. A little labor sure beats $$$ for new bearings. However, if there's a lot of miles on it(upper 100k or better), then I might consider hubs as the 1999 and up do frequently need them. 88-98, not so much...

Also, clean both sensor pads. It may be only one side causing unwanted activation, but the other will be almost as rusty and on the verge of causing problems.

[cjac]

A little labor led to corroded sensor surfaces being the culprit. Simple as that, hardest part is getting to the sensors. 5 minutes to clean them up. You just need to make sure they're still flat and not warped.

Good news is I got to check out pad and rotor wear obviously, both sides look really good, with even wear (but minimal wear really) on both pads and rotors.

It's the Mrs' truck, its paid for, doesn't look like or ride like a 2001, so having the brakes checked off the list is a big win. Nice to catch a break once in a while!

Thanks for the info boys,

Chris

[Macgyver55]

Glad it worked out for you!

[cjac]

Agreed! Your advice was spot-on, thanks again Macgyver55 and to all of you for the input!