Vehicle Shakes or Vibrates at Highway Speeds - keywords brake drag front grab intermittent pad pads rotor shake spot spots vibration
| Subject: | Vehicle Shakes or Vibrates at Highway Speeds |
| Models: | 2007 Buick Rainier |
| 2007-2008 Chevrolet Trailblazer models |
| 2007-2008 GMC Envoy models |
| 2007-2008 Saab 97x models |
This PI was superceded to to include 2008 Chevrolet, GMC and Saab vehicles. Please discard PIT4540.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Some customers may comment of an intermittent vibration felt in the vehicle at highway speeds. This vibration may be intermittent and typically will start gradually, increase while driving , then may fade away as the vehicle maintains highway speeds. This vibration may be more severe one time verses the next time. Inspection of the front rotors may reveal blue or black spots or better known as "hot spots".
Recommendation/Instructions:
Replace both the brake booster and master cylinder to correct this concern. If this vehicle has had both the master cylinder and brake booster replaced for this concern once before, please contact Technical Assistance for further direction.
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.
