Primary Supply Reservoir Safety Valve Operational Check Operational Check

1. Block the wheels.
2. Apply the parking brake.
3. Start the engine.
4. Charge the air system to the air compressor governor cut-out point.
5. Stop the engine.



6. Pull out the exposed end of the valve stem. Air should exhaust from the safety valve exhaust port.

If air does not exhaust from the safety valve exhaust port, replace the safety valve.

7. Release the valve stem. The air flow from the exhaust port should stop.

If the air flow does not stop, replace the safety valve.

8. Remove the wheel blocks.

Primary Supply Reservoir Safety Valve Operational Check Leakage Test

1. Block the wheels.
2. Apply the parking brake.
3. Start the engine.
4. Charge the air system to the air compressor governor cut-out point.
5. Stop the engine.
6. Inspect the safety valve exhaust port for air leakage. Air leakage less than a 25.4 mm (1 in) bubble in 5 seconds is acceptable.

If air leakage is excessive, replace the safety valve.

7. Remove the wheel blocks.