GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 1999 🢒 Montana 🢒 Brakes 🢒 Antilock Brake System 🢒 Traction Control System Motor Pack Replacement

Removal Procedure

    Object Number: 155154 Size: SH

    Important: Use care when handling the motor pack. Replace the motor pack if the motor pack are dropped or damages during handling. No repair of the motor pack is authorized. Replace as an assembly.

  1. Remove the 4-way motor pack electrical connector (3) from TCS modulator (2).
    2. 1.1. Use the following procedure in order to remove all four brake pipes (1):

            Important: Use care when handling the motor pack to avoid damaging the motor pack connector. Make sure brake fluid does not accidentally intrude into the motor pack. Brake fluid in the motor pack may cause a premature failure of the motor pack.

    1.2. Place a shop cloth on top of the TCS motor pack in order to catch any dripping fuild.
    1.3. Plug the open brake pipes in order to prevent fuild loss and contamination.
  2. Remove the bolt (4) attaching the front of the TCS hydraulic modulator/motor pack assembly (2) to the mounting bracket.
  3. Lean the TCS modulator assembly (2) forward then remove from vehicle.
  4. Remove the three Torx®head screws that attach gear cover to TCS hydraulic modulator.
  5. Remove gear cover.
  6. Remove the two Torx® head screws that attach the motor pack (1) to TCS modulator.
  7. Remove the motor pack assembly (1).

Installation Procedure

    Object Number: 155168 Size: SH
  1. With TCS modulator positioned upside down rotate each TCS modulator gear clockwise until movement stops.
  2. The above procedure will cause the following conditions:
    3. • The pistons on the TCS modulator will be positioned very close to the bottom of the modulator bore.
    • The brake bleeding procedure becomes simplified.
  3. Install the motor pack assembly to TCS modulator.

    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.

    Important: Use care when handling the motor pack. Replace the motor pack if the motor pack are dropped or damages during handling.

  4. Install the two Torx® head screws that attach the motor pack (1).

    5. Tighten
    Tighten the Torx® head screws to 4.5 N·m (40 lb in).

  5. Install gear cover onto the TCS hydraulic modulator.
  6. Install the three Torx® screws.

    7. Tighten
    Tighten the Torx® head screws to 4 N·m (35 lb in).


    Object Number: 155154 Size: SH
  7. Install the TCS hydraulic modulator/motor assembly (2) to the mounting bracket.
  8. Install the bolt (4) attaching the TCS assembly (2) to the mounting bracket.

    9. Tighten
    Tighten the bolt to 9 N·m (80 lb in).

  9. Install the four brake pipes (1) to the TCS modulator assembly (2).

    10. Tighten
    Tighten all four brake tube nuts to 24 N·m (18 lb ft).

  10. Connect the TCS motor pack 4-way electrical connector (3).
  11. Bleed the system. Refer to Hydraulic Brake System Bleeding in brakes.