2004 silverado SS AWD brake help

PittSpeed Automotive
1

Here’s the dilemma im having with the truck. When i slow down and go to stop (this usually happens at around 15 mph) the pedal chatters and the truck will drift then grab. The pedal must be pressed farther for the brakes to bite. Also, when i went to pull into my driveway the ABS light went on and off a few times. I changed the back rotors and pads about 3 months ago. Does that sound like just bad front brakes or maybe more?

thanks in advance

Jake

2

Subject: Antilock Brake (ABS) Activation At Low Speeds (Clean Wheel Speed Sensor Mounting Surface)

Models: 2002-2006 Cadillac Escalade, Escalade EXT
2003-2006 Cadillac Escalade ESV
1999-2006 Chevrolet Silverado
2001-2006 Chevrolet Suburban, Tahoe
2002-2006 Chevrolet Avalanche
2003-2006 Chevrolet Express
2007 Chevrolet Silverado Classic
1999-2006 GMC Sierra
2001-2006 GMC Yukon, Yukon Denali, Yukon XL, Yukon Denali XL
2003-2006 GMC Savana
2007 GMC Sierra Classic
2003-2006 HUMMER H2

This bulletin is being revised to add the 2007 Silverado/Sierra Classic models. Please discard Corporate Bulletin Number 03-05-25-007C (Section 05 – Brakes).
Condition

Some customers may comment on ABS activation at low speeds, usually below 8 km/h (5 mph). Upon investigation, the technician will find no DTCs set.
Cause

The cause of this condition may be an increased air gap between the wheel speed sensor and the hub reluctor ring due to rust and debris built up on the sensor mounting surface.
Correction

Measure AC voltage and clean the wheel speed sensor mounting surfaces.

  1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in the General Information sub-section of the Service Manual.
  2. Disconnect both the front wheel speed sensor connectors at the frame and harness.
  3. Place a Digital Volt Meter (DVM) across the terminals of each wheel speed sensor connector.
  4. Rotate the wheel clockwise approximately one revolution per second. The minimum reading should be at least 350 ACmV’s. If the reading is less than 350 ACmV’s, remove the wheel speed sensor. Refer to the applicable Wheel Speed Sensor Replacement procedure in the ABS sub-section of the Service Manual.
  5. Plug the wheel speed sensor bore in order to prevent debris from falling into the hub during service.
  6. Clean the wheel speed sensor mounting surface using a wire brush, sand paper, emery cloth, scotch brite, or other suitable material. Be sure to thoroughly clean the wheel speed sensor surface. There should be no rust or corrosion.
  7. Check the sensor head to determine if it has been warped/distorted due to the corrosion build up or other causes. Check the mounting surface on the sensor head for flatness by placing it on the edge of a metal machinists scale or other suitable straight edge to measure the flatness. Check the sensor for flatness in multiple (minimum 3) positions/directions. If the sensor head is distorted, replace the sensor.
  8. Apply (spray) two thin coats of the specified rust penetrating lubricant (corrosion inhibitor) to the complete sensor mounting surface on the bearing hub. Allow to dry for 3-5 minutes between coats. Use ONLY Rust Penetrating Lubricant, P/N 89022217 (in Canada, P/N 89022218).
  9. When the corrosion inhibitor is dry to the touch (about 10 minutes), apply a thin layer of bearing grease to the hub surface and sensor O-ring prior to sensor installation. Use ONLY Wheel Bearing Lubricant, P/N 01051344 (in Canada, P/N 993037).
  10. Install either the original sensor or a new one in the hub. Ensure that the sensor is seated flush against the hub. Refer to the applicable Wheel Speed Sensor Replacement procedure in the ABS sub-section of the Service Manual.
  11. Place the DVM across the sensor terminals and recheck the voltage while rotating the wheel. The voltage should now read at least 350 ACmV’s.
3

there was a recall a few years ago to get all trucks fixed.

my blazer does this and the easy fix was to pull the abs fuse for time being till you can get it fixed.

4

pull out front abs wire going to each wheel,clean rust on flat area where the plug sets on wheel bearing do same to wire,grease reinstall

5

yeah, this is a common problem. 3 guys where I work drive 4wd chevy trucks and 2 of them have had this same problem.

6

mine does it and now i know how to fix it.:burnout:

7

work van has had this issue for a year and the tech keeps telling my boss there is no problem… i am printing that shit out

8

i just bought a silverado at the auction that does the same thing.

9

Thanks for the sensor Brian. And all the advice. I finally read this post.

10

You are getting unintended ABS. I see it all the time. The quick diagnosis is to hit brakes with hands off wheel around 5mph, see which way the wheel pulls. Pull to the left, right side sensor, to the right, left side sensor. no pull, make sure it’s the front and replace both. Where I work we have been getting the whole sensor/bearing assembly cheaper than we can get just the sensor. Hope this helps

11

NAPA sales the sensors for ~$37.00. I’m sure the sensor/bearing assembly has to be more that that.