Air Brake Safety Valve Deploys for GMC Truck TopKick C-Series (Conventional) C6/C7/C8 2003

Restriction in delivery lines

Inspect the delivery lines to reservoir for a restriction. Repair as needed.

Safety valve malfunction

Verify relief pressure is at manufacturer specifications, typically 150 psi. Replace if necessary.

Check if the governor cut-out adjustment is too high.

Refer to Air Compressor and Governor Valve Diagnosis .