| Subject: | Squeak Noise On Brake Apply |
| Models: | 2008 Buick Enclave |
| 2007 Cadillac Escalade, Escalade ESV, Escalade EXT |
| 2007 Chevrolet Avalanche, Silverado, Suburban, Tahoe |
| 2004-2007 Chevrolet Trailblazer, Trailblazer EXT and Trailblazer SS |
| 2005-2007 Chevrolet Silverado Classic with RPO JF3 or JF7 |
| 2004-2007 GMC Envoy, Envoy XL and Envoy XUV |
| 2007 GMC Sierra, Yukon, Yukon Denali, Yukon XL, Yukon Denali XL |
| 2005-2007 GMC Sierra Classic with RPO JF3 or JF7 |
This PI was superseded to update models. Please discard PIT3779C.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Owners may comment on a squeak noise when the brake pedal is applied or when released. This noise is normally heard when the brake pedal is slowly applied with the engine on or off but can occur when the brake pedal is released. The noise may be isolated
to the master cylinder area.
Recommendation/Instructions:
To correct this concern flush out the brake fluid with a DOT 3 brake fluid. It is recommended to use the equivalent DOT 3 brake fluid in place of the Delco Supreme 11® (GM P/N 12377967). Remove as much of the fluid from the master cylinder as possible
and fill with the equivalent DOT 3. Use the proper "Hydraulic Brake System Bleed" procedure in SI and flush out the old brake fluid. After completing fill the brake master cylinder reservoir to the maximum-fill level with the equivalent DOT-3 brake fluid.
Note: The noise may not be completely eliminated after the flush procedure. It may take several brake applies before the noise is completely eliminated.
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.
