GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 1998 🢒 Silhouette 🢒 Brakes 🢒 Antilock Brake System 🢒 Brake Modulator Replacement

Removal Procedure

    Object Number: 183893 Size: MH
  1. Remove ABS brake modulator/master cylinder assembly from vehicle. Refe to Brake Modulator/Master Cylinder Assembly Replacement .
  2. Remove the gear cover (3). Refer to Modulator Gear Cover Replacement .
  3. Remove the ABS brake motor pack (1). Refer to ABS Motor Pack Replacement .
  4. Remove two ABS brake modulator to master cylinder banjo bolts (2).
  5. Separate the brake modulator (6) from the master cylinder (8).
  6. Remove two transfer tubes (7) with O-rings from both the master cylinder (8) and the ABS brake modulator (6).
  7. Make sure that both old banjo O-rings are remove from the master cylinder (8) and the ABS brake modulator (6).

Installation Procedure

    Object Number: 183893 Size: MH

    Important: No repair of the ABS brake modulator is authorized. Replace the ABS brake modulator as an assembly.

    Important: When replacing the ABS brake modulator install the three gears in the same location on the replacement brake modulator. Refer to Brake Modulator Gear Replacement .

    Important: Use new transfer tube assemblies when assembling the ABS brake modulator/master cylinder assembly. Be sure to properly install two new O-rings on each transfer tube. Do not try to reuse old O-rings.

  1. Use the following procedure in order to install the two transfer assemblies.
  2. Clamp the mounting flange of the master cylinder in a vise.
  3. Lubricate the new transfer tubes assembly that includes O-rings with clean brake fluid.
  4. Insert the transfer tube assemblies (7) all the way in by hand into the master cylinder ports (8).
  5. Hold the ABS brake modulator (6) and rock the modulator onto the other end of transfer tube assemblies (7) already installed in master cylinder.
  6. Lubricate the new banjo bolts O-ring with clean brake fluid.

    7. 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.

  7. Install the two new banjo bolts with O-ring into the ABS brake modulator (6) and the master cylinder (8).

    8. Tighten
    Tighten the banjo bolts to 24 N·m (17 lb ft).

  8. With the ABS brake modulator positioned upside down and the gears facing you rotate each ABS brake modulator gear clockwise until movement stops.

    9. The procedure causes the following conditions:

    • The pistons are positioned very close to the top of the modulator bore.
    • The brake bleeding procedure is simplified.
  9. Install the ABS brake motor pack (1) onto the ABS brake modulator/master cylinder assembly. Refer to ABS Motor Pack Replacement .
  10. Install the gear cover (3) to the ABS brake modulator/master cylinder assembly. Refer to Modulator Gear Cover Replacement .
  11. Install ABS brake modulator/master cylinder assembly. Refer to Brake Modulator/Master Cylinder Assembly Replacement .
  12. Perform brake bleed. Refer to Hydraulic Brake System Bleeding located in hydraulic brakes.