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

Removal Procedure
  1. Block the wheels.
  2. Drain all of the air reservoirs. Refer to Air Brake Reservoir Draining.
  3. Remove the air lines from the relay valve. Refer to Hose and Line Replacement - Nylon Push-In Type Fitting.
  4. Tag or label the lines for installation.
  5. Remove the following components:
    6. • The nuts
    • The washers
    • The bolts

    Object Number: 227932 Size: SH
  6. Remove the relay valve right side.

    7. Object Number: 227935 Size: SH
  7. Remove the relay valve left side.
  8. Inspect the air lines for the following conditions:
    9. • Damage
    • Kinks
    • Wear
  9. Replace any damaged, kinked, or worn air lines.

Installation Procedure

    Object Number: 227932 Size: SH
  1. Install the relay valve left side.

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


    Object Number: 227935 Size: SH
  2. Install the relay valve right side.

    3. Tighten
    Tighten the relay valve bolts to 52 N·m (38 lb ft).

  3. Install the air lines to the relay valve. Refer to Hose and Line Replacement - Nylon Push-In Type Fitting.
  4. Perform the air leakage test. Refer to Rear Air Brake Relay Valve Operational Check.
  5. Perform the operational test. Refer to Rear Air Brake Relay Valve Leakage Test.
  6. Remove the wheel blocks.