GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2005 🢒 GTO 🢒 Engine 🢒 Engine Electrical 🢒 Master Cylinder Replacement

Removal Procedure
  1. Apply the brake pedal at least 5 times in order to exhaust the vacuum in the brake booster.
  2. Remove the front suspension support brace. Refer to Front Suspension Support Brace Replacement.

    3. Object Number: 1547488 Size: SH
  3. Clean the following components:
    4. • The brake fluid reservoir cap
    • The brake fluid reservoir
    • The master cylinder (5)
    • The brake pipes (3,4) around the master cylinder
  4. Use a flat-bladed tool in order to lift the connector security clip on the brake fluid level switch connector.
  5. Disconnect the brake fluid level switch connector.
  6. Place a container below the master cylinder in order to catch the brake fluid.
  7. Remove the reservoir cap.
  8. Remove the cap seal.

    9. Caution: Refer to Brake Fluid Irritant Caution in the Preface section.

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

  9. Remove the brake fluid with the syringe.
  10. Loosen the 2 flare nuts and separate the 2 brake pipes from the master cylinder.
  11. Install caps or plugs to the brake pipes in order to prevent brake fluid loss and contamination.
  12. Install caps or plugs to the master cylinder ports in order to prevent contamination.
  13. Remove the 2 nuts (8,9) from the bracket (10).
  14. Remove the bolt (7) and the washer (6) from the bracket.
  15. If the vehicle has a manual transmission, use a tie strap, or equivalent, in order to secure the bracket and the clutch fluid reservoir in an upright position.
  16. If the vehicle has an automatic transmission, remove the bracket.
  17. Remove the 2 nuts (1,2) from the master cylinder.

    18. Object Number: 1547595 Size: SH

    Important: Do not push the booster push rod or the brake pedal.

  18. Remove the master cylinder assembly (4).
  19. Remove and discard the O-ring (3).
  20. Remove the reservoir and the reservoir seals, if necessary. Refer to Master Cylinder Reservoir Replacement.

Installation Procedure
  1. Install the reservoir and the reservoir seals, if necessary. Refer to Master Cylinder Reservoir Replacement.

    2. Object Number: 1547595 Size: SH
  2. Install a NEW O-ring (3) to the master cylinder (4).
  3. Install the master cylinder assembly to the vacuum brake booster.

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


    Object Number: 1547488 Size: SH
  4. Install the 2 nuts (1,2) to the booster studs.

    5. Tighten
    Tighten the nuts to 10 N·m (88.5 lb in).

  5. If the vehicle has a manual transmission, remove the tie strap, or equivalent, and place the clutch fluid reservoir in the correct position.
  6. Install the bracket (10).
  7. Install the washer (6) and the bolt (7) to the bracket.

    8. Tighten
    Tighten the bolt to 10 N·m (88.5 lb in).

  8. Install the 2 nuts (8,9) to the bracket.

    9. Tighten
    Tighten the nuts to 8 N·m (70.8 lb in).

  9. Place a container under the master cylinder in order to catch the brake fluid.
  10. Remove the caps or the plugs from the brake pipes and the master cylinder.
  11. Push the 2 brake pipes (3,4) into the master cylinder ports.

    12. Caution: Refer to DOT 4 Brake Fluid Caution in the Preface section.

    Notice: When adding fluid to the brake fluid reservoir or to the clutch fluid reservoir, use only Super DOT-4 or equivalent DOT-4 brake fluid from a clean, sealed container. This polyglycol brake fluid is hygroscopic and absorbs moisture. Do not use fluid from an open container that may be contaminated with water. Improper or contaminated fluid could result in damage to the system components.

    Important: Ensure the brake fluid level stays above half-full.

  12. Fill the reservoir with GM Vehicle Care® Brake and Clutch Fluid, GM P/N 88958860, or the equivalent DOT-4 brake fluid. Refer to Master Cylinder Reservoir Filling.
  13. Allow the fluid to drip from the ports for approximately 1 minute.
  14. Tighten the 2 flare nuts.

    15. Tighten
    Tighten the 2 flare nuts to 14 N·m (10 lb ft).

  15. Bleed the brakes. Refer to Hydraulic Brake System Bleeding.
  16. Fill the reservoir. Refer to Master Cylinder Reservoir Filling.
  17. Install the cap seal.
  18. Install the cap.
  19. Remove the container from below the master cylinder.
  20. Connect the brake fluid level switch connector.
  21. Install the connector security clip on the brake fluid level switch connector.
  22. Install the front suspension support brace. Refer to Front Suspension Support Brace Replacement.