GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Brakes 🢒 Air Brakes 🢒 Trailer Brake Control Valve Replacement

Removal Procedure
  1. Block the wheels.
  2. Drain the air reservoirs. Refer to Air Brake Reservoir Draining .
  3. Remove the console assembly.
  4. Remove the air lines from the trailer air brake control valve. Refer to Hose and Line Replacement - Nylon Push-In Type Fitting .

    5. Object Number: 1491979 Size: SH
  5. Remove the nuts, the washers, and the bolts.
  6. Remove the trailer air brake control valve.
  7. Inspect the air lines for the following:
    8. • Damage
    • Kinks
    • Wear
  8. Replace or repair the air lines as necessary.

Installation Procedure

    Object Number: 1491979 Size: SH
  1. Install the trailer air brake control valve.

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

  2. Install the bolts, the washers, and the nuts.

    3. Tighten
    Tighten the trailer air brake control valve bolts to 40 N·m (29 lb ft).

  3. Install the air lines to the trailer air brake control valve.
  4. Perform the air leakage test. Refer to Trailer Brake Control Valve Leakage Test .
  5. Perform the operational test. Refer to Trailer Brake Control Valve Operational Check .
  6. Remove the wheel blocks.