Vacuum Brake Booster: Service and Repair

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




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

Important: 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 it out of the way.




10. Disconnect the vacuum check valve (2) from the vacuum booster.
11. Remove the inlet heater pipe from the bracket at the transmission.
12. Remove the left closeout insulator panel.
13. Remove the left knee bolster.
14. To access the left lower brake pedal to vacuum brake booster mounting nut, remove the steering column mounting nuts.
15. Lower the steering column and secure it.




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




19. Remove the vacuum brake booster mounting nuts (1) from the brake pedal assembly.
20. Raise the vehicle. Refer to Vehicle Lifting.




21. Support the front frame with jack stands.
22. Loosen the left side bolts from the frame to the body. Refer to Frame Replacement - Front.
23. Lower the left side frame 2-3 inches to gain enough clearance to remove the brake booster. Refer to Frame Replacement - Front.




24. Remove the vacuum brake booster from the vehicle.

Important: The gasket does not have to be replaced every time the booster is removed. Replace the gasket only if necessary.

25. Remove the vacuum brake booster mounting gasket.

Installation Procedure




1. Install the vacuum brake booster mounting gasket to the booster, if removed previously.
2. Install the vacuum brake booster to the vehicle.
3. Lower the vehicle onto the engine frame. Refer to Frame Replacement - Front.
4. Remove the jack stands.
5. Lower the vehicle.





Notice: Refer to Fastener Notice.

6. Install the brake pedal assembly to booster stud mounting nuts (1) to the booster studs.

Tighten the brake pedal assembly to booster stud mounting nuts to 30 N.m (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 retainer clip (2) to the brake pedal assembly clevis pin.
11. Install the steering column.
12. Install the steering column mounting attaching nuts.
13. Install the left knee bolster.
14. Install the left closeout insulator panel.




15. Install the inlet heater pipe.
16. Install the shift control cable to the shift cable bracket.
17. Position the gearshift lever into park.




18. Install the brake booster vacuum check valve (2) to the vacuum brake booster.
19. Install the master cylinder to the vacuum brake booster.
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.
* For the lines that have the metal connectors, refer to Metal Collar Quick Connect Fitting Service.

21. Remove the blocks from the front wheels.
22. Release the parking brake.