GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2008 🢒 Enclave 🢒 Brakes 🢒 Hydraulic Brakes 🢒 Power Vacuum Brake Booster Replacement

Removal Procedure
  1. Place the vehicle on a level surface and apply the park brake.
  2. With the engine OFF, apply and release the brake pedal several times until the brake pedal becomes firm to deplete the vacuum reserve in the vacuum brake booster.
  3. Remove the air cleaner assembly. Refer to Air Cleaner Assembly Replacement.
  4. Remove the windshield washer solvent heater. Refer to Windshield Washer Solvent Heater Replacement.

    5. Object Number: 1862134 Size: SH
  5. Disconnect the master cylinder fluid level sensor electrical connector (1).
  6. Remove the vacuum brake booster check valve and hose assembly (2) from the vacuum brake booster and position aside.
  7. Remove the vacuum brake booster vacuum sensor (3) and position aside.

    8. Object Number: 1862135 Size: SH
  8. Release the front and rear brake pipes (1) from the routing clip on the frame rail.
  9. Remove the 2 nuts (2) from the brake pressure modulator valve (BPMV) assembly.

    10. Important: It is not necessary to disconnect the brake pipes from the BPMV assembly.

  10. Carefully lift the BPMV assembly over the studs and position forward slightly.

    11. Object Number: 1862137 Size: SH
  11. Remove the 2 brake master cylinder nuts.

    12. Important: It is not necessary to disconnect the brake pipes from the master cylinder.

  12. Without disconnecting the brake pipes from the master cylinder, remove the master cylinder assembly and position aside.

    13. Place the brake master cylinder in an upright position and support with heavy mechanics wire or equivalent.


    Object Number: 1862139 Size: SH
  13. Remove the left side instrument panel insulator panel. Refer to Instrument Panel Insulator Panel Replacement - Left Side.
  14. Remove the driver knee bolster. Refer to Driver Knee Bolster Replacement.
  15. Remove the brake pedal pushrod retaining clip (1).
  16. Remove the brake pedal pushrod clevis pin (2) and disconnect the pushrod from the brake pedal.
  17. Remove the intermediate steering shaft. Refer to Intermediate Steering Shaft Replacement.

    18. Object Number: 1862142 Size: SH
  18. Remove the 4 vacuum brake booster nuts.

    19. Object Number: 1862147 Size: SH
  19. Pull the vacuum brake booster forward and tilt upward slightly until the mounting studs clear the dash panel.
  20. Remove the vacuum brake booster.

Installation Procedure

    Important: Inspect the vacuum brake booster to dash panel gasket for damage and replace, if necessary.


    Object Number: 1862147 Size: SH
  1. Align the vacuum brake booster mounting studs to the dash panel.
  2. Install the vacuum brake booster.

    3. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 1862142 Size: SH
  3. Install the 4 vacuum brake booster nuts.

    4. Tighten
    Tighten the nuts to 25 N·m (18 lb ft).

  4. Install the intermediate steering shaft. Refer to Intermediate Steering Shaft Replacement.

    5. Object Number: 1862139 Size: SH
  5. Connect the brake pedal pushrod to the brake pedal and install the clevis pin (2).
  6. Install the brake pedal pushrod retaining clip (1).
  7. Install the driver knee bolster. Refer to Driver Knee Bolster Replacement.
  8. Install the left side instrument panel insulator panel. Refer to Instrument Panel Insulator Panel Replacement - Left Side.

    9. Important: Ensure the master cylinder to vacuum brake booster seal is properly installed on the back of the master cylinder housing and is not damaged.


    Object Number: 1862137 Size: SH
  9. Position the master cylinder to the vacuum booster. Inspect the master cylinder to vacuum brake booster seal for damage and replace, if necessary.
  10. Install the 2 brake master cylinder nuts.

    11. Tighten
    Tighten the nuts to 20 N·m (15 lb ft).


    Object Number: 1862135 Size: SH
  11. Position the BPMV assembly over the studs.
  12. Install the 2 nuts (2) to the BPMV and bracket assembly.

    13. Tighten
    Tighten the nuts to 20 N·m (15 lb ft).

  13. Install the front and rear brake pipes (1) to the routing clip on the frame rail.

    14. Object Number: 1862134 Size: SH
  14. Connect the master cylinder fluid level sensor electrical connector (1).

    15. Important: If necessary, a small amount of denatured alcohol may be used to aid installation of the brake booster vacuum sensor. Do not use soap.

  15. Install the vacuum brake booster vacuum sensor (3).

    16. Important: If necessary, a small amount of denatured alcohol may be used to aid installation of the brake booster check valve. Do not use soap.

  16. Install the vacuum brake booster check valve and hose assembly (2) to the vacuum brake booster.
  17. Install the windshield washer solvent heater. Refer to Windshield Washer Solvent Heater Replacement.
  18. Install the air cleaner assembly. Refer to Air Cleaner Assembly Replacement.