Silverado 1500 4WD V8-6.0L Hybrid (2009)
Hydraulic System Junction Block: Service and Repair
Brake Pipe Manifold Replacement
Removal Procedure
Warning
The high pressure accumulator (HPA) and the chambers of the brake modulator assembly to which it attaches, store brake fluid at extremely high
pressures. Fluid pressure must be relieved before attempting to service the HPA. Ensure that the recommended procedures are followed to relieve system
pressure, including using the manual pressure release steps. Failure to properly follow procedures to depressurize the system may result in personal
injury.
Warning: Refer to Brake Fluid Irritant Warning.
Caution: Refer to Brake Fluid Effects on Paint and Electrical Components Caution .
Note
The ignition must be in the OFF position, without pausing at ACCESSORY, and without applying the brake pedal to ensure the brake modulator and
high pressure accumulator (HPA) pressure relief occurs. This process will take approximately 1 to 3 minutes.
1. Turn the ignition to OFF, without pausing at ACCESSORY, and remove the ignition key.
2. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
3. Clean any dirt and debris from the brake modulator assembly and the brake pipe manifold.
Note
To ensure brake modulator and HPA pressure relief has occurred, the manual pressure relief valve must be opened momentarily.
4. Loosen the brake modulator manual pressure relief valve (1) 1/4 turn counterclockwise.
5. Seat, but do not tighten, the manual pressure relief valve.
6. Remove the brake pressure modulator valve assembly. Refer to Brake Pressure Modulator Valve Replacement .