GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2000 🢒 LeSabre 🢒 Brakes 🢒 Hydraulic Brakes 🢒 Master Cylinder Replacement

Removal Procedure
  1. Remove the electrical connector from the fluid level sensor.
  2. Remove the brake pipes from the master cylinder.
  3. Plug the open pipes to prevent fluid loss and contamination.

    4. Object Number: 420706 Size: SH
  4. Remove the two master cylinder nuts.
  5. Remove the master cylinder.
  6. Remove the reservoir if it is to be used on the replacement master cylinder. Refer to Master Cylinder Reservoir Replacement .

Installation Procedure
  1. Install the reservoir onto the master cylinder. Refer to Master Cylinder Reservoir Replacement .
  2. Bench bleed the master cylinder. Refer to Master Cylinder Bench Bleeding .

    3. Object Number: 420706 Size: SH
  3. Install the master cylinder onto the power booster.

    4. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  4. Install the master cylinder nuts.

    5. Tighten
    Tighten the master cylinder nuts to 25 N·m (18 lb ft).

  5. Install the brake pipes to the master cylinder.

    6. Tighten
    Tighten the brake pipe to master cylinder nuts to 33 N·m (24 lb ft).

  6. Install the electrical connector to the fluid level sensor.

    7. Notice: When filling the master cylinder, use only Delco Supreme 11, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT 3 brake fluid. Do not use a container which has been used for petroleum based fluids, or a container which is wet with water. Petroleum based fluids will cause swelling and distortion of rubber parts in the hydraulic brake system, and water will mix with brake fluid, lowering the boiling point. Keep all fluid containers capped to prevent contamination.

  7. Fill the master cylinder reservoir to the full level mark using only Delco® Supreme II Brake Fluid, GM P/N 12377967, or equivalent DOT 3 brake fluid.
  8. Bleed the hydraulic brake system. Refer to Hydraulic Brake System Bleeding .