Air Brake Dryer Testing for Chevrolet Chevy P42 Commercial Chassis 1997

1. Set the parking brake.
2. Drain the air reservoirs. Refer to Draining Reservoirs .
3. Start the engine. Charge the air system to the governor cut-out point.
4. Verify that an exhaust of air occurs at the air dryer exhaust port. This is the air dryer purge cycle.
5. If the air dryer does not cycle properly, check the system for leaks at the air line connections and in the air brake system. Replace the air dryer if necessary.