GM Service Manual Online
For 1990-2009 cars only

Warning: Refer to Brake Fluid Irritant Warning in the Preface section.

Caution: Refer to Brake Fluid Effects on Paint and Electrical Components Caution in the Preface section.

Removal Procedure

  1. Apply and release the brake pedal several times until the brake pedal becomes firm to deplete the brake booster vacuum reserve.

  2. Object Number: 1912258  Size: SH
  3. Disconnect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection.
  4. Without disconnecting the wiring harness connectors, reposition the electrical center and the powertrain control modules from the underhood electrical center bracket and remove the bracket. Refer to Underhood Electrical Center or Junction Block Bracket Replacement.
  5. Disconnect the brake fluid level indicator switch electrical connector.
  6. Disconnect the master cylinder secondary brake pipe fitting (1).
  7. Cap the brake pipe fitting and plug the master cylinder outlet port to prevent brake fluid loss and contamination.


    Object Number: 1912261  Size: SH
  8. Disconnect the master cylinder primary brake pipe fitting (1).
  9. Cap the brake pipe fitting and plug the master cylinder outlet port to prevent brake fluid loss and contamination.


    Object Number: 1912265  Size: SH
  10. Remove the brake master cylinder nuts (1).

  11. Object Number: 1912266  Size: SH
  12. Disconnect the master cylinder clutch hose quick connect fitting (1) from the clutch master cylinder, if equipped.
  13. Plug the master cylinder clutch hose and cap the clutch master cylinder inlet port to prevent brake fluid loss and contamination.

  14. Remove the master cylinder.

  15. Object Number: 1912268  Size: SH
  16. Remove the master cylinder to vacuum brake booster seal (1) from the master cylinder.

Installation Procedure

  1. Bench bleed the master cylinder. Refer to Master Cylinder Bench Bleeding.

  2. Object Number: 1912268  Size: SH
  3. Install the master cylinder to vacuum brake booster seal (1) to the master cylinder.
  4. Ensure the seal is fully seated in the groove in the master cylinder body.


    Object Number: 1912266  Size: SH
  5. Position the master cylinder to the vacuum brake booster and connect the master cylinder clutch hose quick connect fitting (1) to the clutch master cylinder, if equipped.
  6. Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 1912265  Size: SH
  7. Install the brake master cylinder nuts (1) and tighten to 22 N·m (16 lb ft).

  8. Object Number: 1912261  Size: SH
  9. Connect the master cylinder primary brake pipe fitting (1) and tighten to 21 N·m (15 lb ft).

  10. Object Number: 1912258  Size: SH
  11. Connect the master cylinder secondary brake pipe fitting (1) and tighten to 21 N·m (15 lb ft).
  12. Install the underhood electrical center bracket and position the electrical center and the powertrain control modules to the electrical center bracket. Refer to Underhood Electrical Center or Junction Block Bracket Replacement.
  13. Connect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection.
  14. Bleed the hydraulic brake system. Refer to Hydraulic Brake System Bleeding.