GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2000 🢒 Firefly (Canada) 🢒 Brakes 🢒 Hydraulic Brakes 🢒 Master Cylinder Replacement

Removal Procedure

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the negative battery cable.
  2. Clean the reservoir cap.
  3. Remove the reservoir cap.
  4. Siphon the fluid from the reservoir.
  5. Disconnect the fluid level switch electrical connector.

    6. Object Number: 178540 Size: SH
  6. Models without ABS: Remove the three brake pipes from the master cylinder (5) by loosening the brake pipe nuts (4).

    7. Object Number: 178541 Size: SH
  7. Models with ABS: Remove the two brake pipes (7) from the master cylinder (6) and the proportioning valve (5) by loosening the brake pipe nuts.
  8. Plug the open brake pipes in order to prevent the contamination and excessive loss of fluid.
  9. Remove two master cylinder mounting nuts and washers.
  10. Remove the master cylinder.
  11. Remove the gasket from the vacuum booster.

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

    2. Object Number: 178540 Size: SH

    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.

  2. Install the master cylinder and the new gasket to the vacuum booster. Secure with two mounting nuts (3) and washers.

    3. Tighten
    Tighten the master cylinder mounting nuts to 13 N·m (115 lb in).

  3. Install the brake pipes to the master cylinder (and the proportioning valve on models with ABS). Secure with brake pipe nuts.

    4. Tighten
    Tighten the master cylinder brake pipe flare nuts to 16 N·m (12 lb ft).

  4. Connect the fluid level switch electrical connector.
  5. Connect the negative battery cable. Refer to Battery Cable Replacement in Engine Electrical.
  6. Bleed the brake system. Refer to Hydraulic Brake System Bleeding .