GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2008 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Brakes 🢒 Air Brakes 🢒 Air Dryer Replacement

Removal Procedure
  1. Block the wheels.
  2. Drain all the reservoirs. Refer to Air Brake Reservoir Draining .
  3. Mark the position and remove the air lines from the air dryer. Refer to Hose and Line Replacement - Nylon Push-In Type Fitting .

    4. Object Number: 1488988 Size: SH
  4. Remove the air dryer-to-frame bolts.
  5. Remove the air dryer assembly.
  6. Clean the air lines and fittings with a dry cloth.
  7. Inspect the air lines for the following conditions:
    8. • Damage
    • Cracks
    • Bulge
    • Wear
  8. If any of the above conditions are present, replace the air lines.
  9. Inspect the air dryer supports for damage and replace as needed.

Installation Procedure

    Object Number: 1488988 Size: SH
  1. Install the air dryer assembly.

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

  2. Install the air dryer-to-frame bolts.

    3. Tighten
    Tighten the air dryer mounting bolts to 85 N·m (63 lb ft).

  3. Install the air lines in the marked proper position. Refer to Hose and Line Replacement - Nylon Push-In Type Fitting .
  4. Start the engine.
  5. Charge the system air pressure to the governor cut-out point.
  6. Check for leaks with a soap solution and repair as needed.
  7. Remove the wheel blocks.