GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2008 🢒 G6 🢒 Brakes 🢒 Hydraulic Brakes 🢒 Master Cylinder Replacement

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.

Removal Procedure

    Object Number: 1961270 Size: SH
  1. Deplete the vacuum reserve from the vacuum brake booster by removing the vacuum check valve (1) from the vacuum brake booster grommet.
  2. Disconnect the brake fluid level indicator switch electrical connector.

    3. Object Number: 1961273 Size: SH
  3. Disconnect the master cylinder secondary brake pipe fitting (1).

    4. Cap the brake pipe fitting and plug the master cylinder outlet port to prevent brake fluid loss and contamination.


    Object Number: 1961279 Size: SH
  4. Disconnect the master cylinder primary brake pipe fitting (1).

    5. Cap the brake pipe fitting and plug the master cylinder outlet port to prevent brake fluid loss and contamination.


    Object Number: 1961282 Size: SH
  5. Remove the master cylinder nuts (1) .
  6. Remove the master cylinder.
  7. Inspect the master cylinder to vacuum brake booster seal for damage and replace, if necessary.
  8. Remove the master cylinder reservoir, if necessary. Refer to Master Cylinder Reservoir Replacement.

Installation Procedure
  1. Install the brake master cylinder reservoir to the master cylinder, if removed. Refer to Master Cylinder Reservoir Replacement.
  2. Bench bleed the master cylinder. Refer to Master Cylinder Bench Bleeding.
  3. Ensure the master cylinder to vacuum brake booster seal is properly seated on the master cylinder barrel.

    4. Object Number: 1961282 Size: SH
  4. Install the master cylinder to the vacuum brake booster.

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

  5. Install the master cylinder nuts (1).

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


    Object Number: 1961279 Size: SH
  6. Connect the master cylinder primary brake pipe fitting (1).

    7. Tighten
    Tighten the fitting to 20 N·m (15 lb ft).


    Object Number: 1961273 Size: SH
  7. Connect the master cylinder secondary brake pipe fitting (1).

    8. Tighten
    Tighten the fitting to 20 N·m (15 lb ft).


    Object Number: 1961270 Size: SH
  8. Install the vacuum check valve (1) to the vacuum brake booster grommet.

    9. If necessary, a small amount of denatured alcohol may be used as a lubricant for assembly. Do not use soap.

  9. Connect the brake fluid level indicator switch electrical connector.
  10. Bleed the hydraulic brake system. Refer to Hydraulic Brake System Bleeding.