Vacuum Brake Booster: Service and Repair

Power Vacuum Brake Booster Replacement

Removal Procedure




1. Place the vehicle on a flat surface.
2. Block the front wheels.
3. Apply the parking brake.
4. To allow access for the removal of the vacuum brake booster, position the gearshift lever into the lowest gear.
5. Remove the air cleaner assembly. Refer to Air Cleaner Assembly Replacement (Service and Repair).
6. Disconnect the fuel vapor lines in front of the brake booster.

* For the lines that have the plastic connectors, refer to Plastic Collar Quick Connect Fitting Service (Plastic Collar Quick Connect Fitting Service).
* For the lines that have the metal connectors, refer to Metal Collar Quick Connect Fitting Service (Metal Collar Quick Connect Fitting Service).




7. Remove the master cylinder mounting nuts (3).

Note: In the following service step, the master cylinder does not have to be removed. Move the master cylinder forward just enough to clear the studs on the vacuum brake booster. This will flex the brake pipes slightly. Do not bend or distort the pipes.

8. Disconnect the master cylinder (1) from the brake booster (2).
9. Disconnect the shift control cable from the shaft lever pin and position aside. Refer to Automatic Transmission Range Selector Cable Replacement - Console (Service and Repair).




10. Disconnect the vacuum check valve (2) from the vacuum booster.
11. Remove the left closeout insulator panel. Refer to Instrument Panel Insulator Panel Replacement - Left Side (Instrument Panel Insulator Panel Replacement - Left Side).
12. Remove the driver knee bolster. Refer to Driver Knee Bolster Replacement (Driver Knee Bolster Replacement).
13. To access the left lower brake pedal to vacuum brake booster mounting nut, remove the steering column mounting nuts. Refer to Steering Column Replacement (Steering Column Replacement).
14. Lower the steering column and support with heavy mechanics wire or equivalent.




15. Remove the vacuum brake booster pushrod retaining clip bolt and retaining clip (2) from the brake pedal clevis pin.
16. Remove the foam spacer (3) from the brake pedal clevis pin.
17. Disconnect the brake booster pushrod from the brake pedal clevis pin.




18. Remove the vacuum brake booster mounting nuts (1) from the brake pedal assembly.




19. Raise and support the front frame with jack stands. Refer to Lifting and Jacking the Vehicle (Service and Repair).
20. Loosen the left side bolts from the frame to the body. Refer to Drivetrain and Front Suspension Frame Replacement (4.6L) (Drivetrain and Front Suspension Frame Replacement (4.6L)).
21. Lower the left side frame 51-76 mm (2-3 in) to gain clearance to remove the brake booster. Refer to Drivetrain and Front Suspension Frame Replacement (4.6L) (Drivetrain and Front Suspension Frame Replacement (4.6L)).




22. Remove the power vacuum brake booster from the vehicle.

Note: Do not reuse the power vacuum brake booster gasket if damaged.

23. Remove the power vacuum brake booster mounting gasket.
Inspect the power vacuum brake booster gasket for damage and replace, if necessary.

Installation Procedure




1. Install the power vacuum brake booster mounting gasket.
2. Install the vacuum brake booster to the vehicle.
3. Lower the vehicle onto the front frame. Refer to Drivetrain and Front Suspension Frame Replacement (4.6L) (Drivetrain and Front Suspension Frame Replacement (4.6L)).
4. Remove the jack stands.
5. Lower the vehicle.





Caution: Refer to Fastener Caution (Fastener Caution).

6. Install the brake pedal assembly to booster stud mounting nuts (1) and tighten to 30 Nm (22 lb ft).




7. Apply a small amount of lubricant, GM P/N 12346293 or equivalent to the clevis pin of the brake pedal.
8. Connect the vacuum brake booster pushrod to the brake pedal clevis pin.
9. Install the foam spacer (3) to the brake pedal clevis pin.
10. Install the retaining clip (2) to the brake pedal assembly clevis pin.
11. Install the power vacuum brake booster pushrod retaining clip bolt and tighten to 7 Nm (62 lb in).
12. Raise the steering column into position.
13. Install the steering column mounting nuts. Refer to Steering Column Replacement (Steering Column Replacement).
14. Install the driver knee bolster. Refer to Driver Knee Bolster Replacement (Driver Knee Bolster Replacement).
15. Install the left closeout insulator panel. Refer to Instrument Panel Insulator Panel Replacement - Left Side (Instrument Panel Insulator Panel Replacement - Left Side).




16. Install the shift control cable to the shift cable bracket. Refer to Automatic Transmission Range Selector Cable Replacement - Console (Service and Repair).
17. Place the gearshift in the PARK position.




18. Install the brake booster vacuum check valve (2) to the vacuum brake booster.
19. Install the master cylinder to the vacuum brake booster. Refer to Master Cylinder Replacement (Removal and Replacement).
20. Connect the fuel vapor lines in front of the brake booster.

* For the lines that have the plastic connectors, refer to Plastic Collar Quick Connect Fitting Service (Plastic Collar Quick Connect Fitting Service).
* For the lines that have the metal connectors, refer to Metal Collar Quick Connect Fitting Service (Metal Collar Quick Connect Fitting Service).