ABS engaging <5mph

strat81

Original poster
Member
Dec 29, 2011
399
My FIL and I replaced the driver's side CV shaft and axle seal this morning. Vehicle is a 2004 Rainier V8 AWD w/ ~76k miles. The hub bearing at this wheel was replaced last year with a unit from Advance Auto.

During the test drive afterwards, I noticed the ABS is engaging when braking at very low speeds - less than 5 mph - and with low pedal pressure.

I can brake from 65 mph with enough force to get stuff to slide off the seat but NOT engaged the ABS. It's only in casual driving, when coming to a complete stop that the ABS engages.

I have two ideas:
1) When removing/installing the wheel speed sensor from the hub, we damaged it.
2) When removing/installing the rotor, we got grease on it.
(Or both)

I got the brakes pretty hot, with multiple stops from highway speeds and pretty heavy pressure on the brakes. I'd think that would be enough to bake off any grease we got on the rotor. When braking at any speed, the vehicle is tracking straight. It is not pulling from to either side. So if we did get grease on the rotor, it wasn't much.

My plan is:
1) Give it a week or so. Maybe the problem will go away.
2) Remove the wheel, caliper, and rotor. Remove the WSS and wipe it with contact cleaner, reinstall it. Hose down the rotor and pad with brake cleaner. Reassemble.
3) if the above doesn't work, replace the WSS. $30 on Amazon.
4) If the above doesn't work, replace the brake pads.

Any ideas on what to check or do before I start throwing parts and money at the problem?? Thanks!
 

Irishboy02

Member
Apr 1, 2012
222
Id say take everything off and disconnect it. Unhook the battery also to let the electronics resets themselves. With being AWD, i believe like many other GM models, it is controlled by braking. If your speed sensor was dirty it would tell the comp that this tire is spinning faster than the others, in a braking situation it would be the equivalent of sliding. I say start there.
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,159
Brighton, CO
Had this problem with my Envoy as well. Turned out the ABS sensor on my right front wheel was bad. Replaced the Wheel Bearing, problem solved.
 

CaptainXL

Member
Dec 4, 2011
2,445
TollKeeper said:
Had this problem with my Envoy as well. Turned out the ABS sensor on my right front wheel was bad. Replaced the Wheel Bearing, problem solved.

How did you know it was the right front wheel bearing?
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,159
Brighton, CO
it was under warrenty, so you would have to ask the dealer that question.
 

Mooseman

Moderator
Dec 4, 2011
25,494
Ottawa, ON
Could also be the hub going bad. Mine did that just before it self destructed (a new Raybestos made-in-china hub). Also had that problem with a new CCC hub in my '00 Jimmy. Try cleaning the sensor and spin the hub by hand to feel for any looseness or roughness in the bearing.

Was there anything on the hub's packaging to indicate its origin?
 

CaptainXL

Member
Dec 4, 2011
2,445
Here is a video about common ABS problems from 0-5 MPH.

[video=youtube;m_YB0RKpQ1k]http://www.youtube.com/watch?v=m_YB0RKpQ1k[/video]
 

strat81

Original poster
Member
Dec 29, 2011
399
Irishboy02 said:
Id say take everything off and disconnect it. Unhook the battery also to let the electronics resets themselves. With being AWD, i believe like many other GM models, it is controlled by braking. If your speed sensor was dirty it would tell the comp that this tire is spinning faster than the others, in a braking situation it would be the equivalent of sliding. I say start there.

Tried rebooting. No satisfaction.

Mooseman said:
Could also be the hub going bad. Mine did that just before it self destructed (a new Raybestos made-in-china hub). Also had that problem with a new CCC hub in my '00 Jimmy. Try cleaning the sensor and spin the hub by hand to feel for any looseness or roughness in the bearing.

Was there anything on the hub's packaging to indicate its origin?

There probably was a country of origin listed, but I don't remember it.

While it is possible the hub is dying, it's a big coincidence for it to happen right after I pulled that side of the car apart.


I appreciate all the ideas and the vid, guys.
 

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