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Brakes??!!

Discussion in 'Chevy Trucks' started by chopper13, Nov 10, 2010.

  1. chopper13

    chopper13 Junior Member
    Messages: 6

    Hey guys. well I seem to have yet another problem. I changed out my front calipers and rotors along with new pads on my 2002 chevy 2500hd. now the ABS comes on when my wheels are about to come to a stop and it pulls right while abs is "crunching". No ABS Light on No brake light on. Any Ideas :help: would be awsome
     
  2. brad96z28

    brad96z28 PlowSite.com Addict
    Messages: 1,526

    Clean the mating surfaces where the abs sensors go on the hub.
     
  3. Q101ATFD

    Q101ATFD Senior Member
    Messages: 277

    Did you let the brake system go dry? If so, you need to have the dealer bleed the air from the ABS system with the Tech II computer.
     
  4. brad96z28

    brad96z28 PlowSite.com Addict
    Messages: 1,526

    I have done over 20 complete brake line jobs on these trucks always letting the master go dry have never had to use my tech 2 on any of them.
     
  5. RepoMan207

    RepoMan207 PlowSite Fanatic
    from Maine
    Messages: 5,033

    I just did all of my lines, bleeding is a *****. You have to keep clearing the ABS error over and over again to get a pedal back.

    I totally agree with Brad, if you disturb the sensors on the hub assemblies, it will also set the error code off.
     
  6. 06Sierra

    06Sierra PlowSite.com Addict
    from Maine
    Messages: 1,329

    I just replaced both hubs on my wife's 04 Yukon for that reason. We pulled out one of the sensors and the plastic that sits inside of the hub was cracked up. I just picked up two new hubs with the sensors. For anyone that needs hubs for one reason or another, autoparts123.com has timken for around $120 each.
     
  7. chopper13

    chopper13 Junior Member
    Messages: 6

    I just replaced both hubs a couple months ago. Also there is NO abs light on. and everything was working fine before. maybe I should try bleeding them some more?
     
  8. Holland

    Holland Senior Member
    Messages: 605

    Listen to brad96z28. You probably have crap between the sensor and hub. The extra clearance causes the abs to activate around 5mph. the system sees nothing wrong, it thinks you just have a wheel slipping. Wont throw a code. try to get the sensor out and clean the mating surfaces.
     
  9. Holland

    Holland Senior Member
    Messages: 605

    As i thought, just like the previous model chevys, there is a tsb on this. here it is.

    TECHNICAL

    Bulletin No.: 03-05-25-007D

    Date: May 01, 2009

    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

    Supercede: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.


    Parts Information







    Place unused material on dealer shelf for future use.

    Warranty Information







    For vehicles repaired under warranty, use the table above.







    Disclaimer
     
  10. chopper13

    chopper13 Junior Member
    Messages: 6

    :mechanic:Thanks for all the info guys! Im gunna put her on the lift tonight after my buddies shop closes.
     
  11. brad96z28

    brad96z28 PlowSite.com Addict
    Messages: 1,526

    do not use anti seze on them either grease only.