Sierra Denali RWD V8-6.2L (2009)
3. Clean any dirt and debris from the brake modulator assembly and the HPA.
Note
To ensure brake modulator and HPA pressure relief has occurred, the manual pressure relief valve must be opened momentarily.
4. Loosen the manual pressure relief valve (1) 1/4 turn counterclockwise.
5. Seat, but do not tighten, the manual pressure relief valve.
Note
Adequately support the brake modulator assembly to avoid placing stress on the brake pipes and hoses.
6. Without disconnecting the brake pipes and hoses, remove the brake pressure modulator assembly bracket. Refer to Brake Pressure Modulator
Valve Replacement () .
7. Remove the HPA (1).
