Power Vacuum Brake Booster Replacement (JL9)

Power Vacuum Brake Booster Replacement (JL9)

Removal Procedure
Warning: Refer to Brake Fluid Irritant Warning (Brake Fluid Irritant Warning).


Caution: Refer to Brake Fluid Effects on Paint and Electrical Components Caution (Vehicle Damage Warnings).

1. Turn the ignition switch to the OFF position.
2. Clean the electronic brake control module (EBCM) to brake pressure modulator valve (BPMV) area and the brake pipe port areas of any accumulated dirt and foreign material.




3. Disconnect the brake fluid level indicator switch electrical connector.
4. Disconnect the vacuum brake booster vacuum sensor electrical connector.




5. Remove the vacuum brake booster check valve and vacuum sensor assembly from the grommet and position aside.




6. Release the wiring harness retainer from the master cylinder mounting stud and position the wiring harness downward.
7. Remove and discard the 2 master cylinder nuts.
8. If equipped, disconnect the clutch master cylinder hose from the brake master cylinder reservoir.
Cap the brake fluid reservoir outlet and plug the clutch master cylinder hose inlet to prevent brake fluid loss and contamination.




9. Remove the 2 master cylinder brake pipe fittings from the BPMV.
Cap the brake pipe fittings and plug the BPMV inlet ports to prevent brake fluid loss and contamination.
10. Remove the brake master cylinder and master cylinder brake pipes as an assembly.




11. Lift the locking tabs on the lower edge of the EBCM electrical connector (1) and disconnect the electrical connector.
12. Position the EBCM electrical connector and the wiring harness toward the front of the vehicle.
13. Release the rear brake pipes retainer (2) from the outboard side of the frame rail.




14. Remove the 3 BPMV bracket bolts.
15. Carefully position the brake modulator assembly forward slightly.




16. Remove the power brake booster pushrod nut (1).




17. Disconnect the vacuum brake booster pushrod (1) from the brake booster pushrod pin.
18. Remove the 4 vacuum brake booster mounting nuts (2).
19. Remove the vacuum brake booster from the vehicle.

Installation Procedure




1. Inspect the vacuum brake booster to dash panel seal (1) for damage and replace, if necessary.
2. Inspect the vacuum brake booster to dash panel gasket (2) for damage and replace, if necessary.
3. Install the vacuum brake booster (3) to the vehicle.
4. Apply a thin coat of high-temperature grease GM P/N 12345996 (Canadian P/N 10953501) to the brake pedal pivot bushing, the pushrod washer, the push rod pin on the pedal, and the brake pedal pivot pin.




5. Connect the vacuum brake booster pushrod (1) to the brake pedal pushrod pin.

Caution: Refer to Fastener Caution (Fastener Caution).

6. Install the 4 vacuum brake booster mounting nuts (2) and tighten to 25 Nm (18 lb ft).




7. Install the power brake booster pushrod nut (1) and tighten to 10 Nm (89 lb in).




8. Carefully position the brake modulator assembly to the frame rail.
9. Install the 3 BPMV bracket bolts and tighten to 11 Nm (97 lb in).




10. Position the EBCM electrical connector and the wiring harness to the EBCM.
11. Connect the EBCM electrical connector (1). Ensure the tabs on the cam lever are securely locked in place.
12. Install the rear brake pipes retainer (2) to the outboard side of the frame rail.




13. Install the brake master cylinder and master cylinder brake pipes assembly to the vacuum brake booster.
14. Install the master cylinder brake pipe fittings to the BPMV and tighten to 20 Nm (15 lb ft).




15. If equipped, connect the clutch master cylinder hose to the brake master cylinder reservoir.
16. Install 2 new brake master cylinder nuts and tighten to 20 Nm (15 lb ft).
17. Position the wiring harness upward and install the wiring harness retainer to the master cylinder mounting stud on the vacuum brake booster.





Note: If necessary, a small amount of denatured alcohol can be used as an assembly aid for installing the check valve to the vacuum brake booster grommet. Do not use soap.

18. Install the vacuum check valve and vacuum sensor assembly to the vacuum brake booster.




19. Connect the brake booster vacuum sensor electrical connector.
20. Connect the brake fluid level indicator switch electrical connector.
21. Bleed the hydraulic brake system. Refer to Hydraulic Brake System Bleeding (Manual) (Service and Repair)Hydraulic Brake System Bleeding (Pressure) (Service and Repair).
22. Calibrate the brake pedal position sensor. Refer to Brake Pedal Position Sensor Calibration (Programming and Relearning).