Removal and Replacement

Power Brake Booster Pump Fluid Accumulator 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 Brake Fluid Irritant Warning.


Caution:
Refer to Brake Fluid Effects on Paint and Electrical Components Caution Brake Fluid Effects on Paint and Electrical Components Caution.

Note:
The transmission must be in the PARK position, the power button in the OFF position, and the brakes not applied to ensure the brake modulator and high pressure accumulator (HPA) pressure relief occurs. This process will take approximately 1 to 3 minutes.

1. Place the transmission in PARK.

2. Place the power button in the OFF position.

3. Remove the remote keyless entry (RKE) transmitter and close all of the vehicle doors.

4. Wait approximately 3 minutes for the HPA pressure relief to occur.

5. Remove the air cleaner resonator outlet duct. Refer to Air Cleaner Resonator Outlet Duct Replacement Air Cleaner Resonator Outlet Duct Replacement.





6. Remove the HPA (1).

7. Remove and discard the HPA O-ring seal (2).

8. Remove any debris from the O-ring seal groove in the brake modulator assembly with a clean, lint-free shop cloth.

9. If replacing the HPA, properly render inert and dispose of the HPA. Refer to Power Brake Booster Pump Fluid Accumulator Disposal Procedures.

Installation Procedure

1. Lubricate a new O-ring seal with GM approved brake fluid from a clean, sealed brake fluid container. Refer to Adhesives, Fluids, Lubricants, and Sealers [1][2]Specifications.





Note:
Ensure the O-ring seal is fully installed in the groove of the HPA.

2. Install the HPA (1) and the O-ring seal (2) to the brake modulator assembly.

Caution:
Refer to Fastener Caution Fastener Caution.

3. Tighten the HPA to 30 Nm (22 lb ft).

4. Install the air cleaner resonator outlet duct. Refer to Air Cleaner Resonator Outlet Duct Replacement Air Cleaner Resonator Outlet Duct Replacement.

5. Perform the Antilock Brake System Automated Bleed Antilock Brake System Automated Bleed. Follow the procedure completely to ensure the learn procedure for the pressure and travel sensors has occurred.