Brake Drag, Pull, Grab, Wear and/or Highway Speed Vibration - keywords assist pad pedal pulsation rotor wheel wear
| Subject: | Brake Drag, Pull, Grab, Wear, and/or Highway Speed Vibration |
| Models: | 2005-2006 Chevrolet Silverado 1500 |
| 2005-2006 GMC Sierra 1500 |
| With RPO JF3 or JF7 |
| Built before Sept. 1, 2005 |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Owners may comment on a brake drag, pull, grab, wear, and/or highway speed vibration. This could be caused by distortion of the vacuum boosters floating control valve. Under high engine vacuum conditions, the brake booster may self apply which could lead to a brake drag. In some cases, a concern of brake pulsation may be noticed due to the brake drag.
Note: When performing diagnostics, be aware this concern is caused by distortion of the floating control valve under high engine vacuum and if the engine is shut off vacuum will be removed and the concern will go away.
Recommendation/Instructions:
To help isolate the concern to the brake booster, pull up lightly on the brake pedal when the concern occurs. If the condition goes away replace the brake booster with updated part number 15840835. This new brake booster was implemented into production September 1, 2005.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
