Front Air Brake Limit Valve Replacement for GMC Truck TopKick C-Series (Conventional) C6/C7/C8 2007

1. Apply the parking brake.
2. Block the wheels.
3. Drain all the reservoirs. Refer to Air Brake Reservoir Draining .
4. Disconnect the air lines at the valve. Refer to Hose and Line Replacement - Nylon Push-In Type Fitting .



5. Remove the mounting bolts (6).
6. Remove the washers (3).
7. Remove the nuts (2).
8. Remove the front axle limiting (ratio) valve (4).

1. Install the front axle limiting (ratio) valve (4).
2. Install the bolts (6).
3. Install the washers (3).

Notice: Refer to Fastener Notice in the Preface section.

4. Install the nuts (2).

Tighten
Tighten the front axle limiting (ratio) valve nuts (2) to 22 N·m (16 lb ft).

5. Connect the air lines. Refer to Hose and Line Replacement - Nylon Push-In Type Fitting .
6. Start the engine.
7. Charge the system air pressure to the governor cut-out point.
8. Stop the engine.
9. Check for air leaks using a soap solution.
10. Check for proper operation.
11. Remove the wheel blocks.