POWER PACK AR 2723400 - Caterpillar

Sudden movement of the machine or release of air under pressure can cause injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the air system and brakes.
Leakage Checks
Note: You can hear the sound of air leakage. Air leakage can be seen when soapy water is applied to connections, valves and hoses.
Start the engine and allow the air pressure to increase to the cut out pressure. Stop the engine.
Check the parking brake control valve in the console to the right of the operator's seat.
Check air lines and fittings at the junction blocks. The junction blocks are located at the top of the tandem housings.
Check all the valves on the air tank.
Check for leakage in the hoses and the connections from the air compressor and the air compressor governor to the air tank.
Check for leakage in hoses, lines, connections, and components from the air tank to the service brake control valve.
Check for leakage in the service brake control valve.
Depress the service brake control (pedal) and hold the service brake control (pedal) down. Check for leakage in hoses, in air lines and in connections from the service brake control valve to the service brakes. Release the pedal.
Check for leakage in the quick-release valve and the parking brake actuator. Place the transmission direction and speed control (lever) to the PARKING BRAKE ENGAGED position.
Make sure that the centershift lock switch is in the ENGAGED position. Check for leakage in hoses, lines, connections, and components from the service brake control valve to the port on the centershift lock pin.
Make sure that the centershift lock switch is in the DISENGAGED position. Check for leakage in hoses, lines, connections, and components from the service brake control valve to the port on the centershift lock pin.
Push down and pull back on the transmission direction and speed control (lever) to the NEUTRAL position. Check for leakage in the hose and in the connections from the parking brake control valve to the parking brake.Note: If the air pressure in the air tank lowers to the cut-in pressure, start the engine and operate the engine. When the air pressure reaches the cut out pressure, stop the engine.Note: When you check the control valves for leakage, check the exhaust passages for any restrictions such as mud or dirt. Restrictions in an exhaust passage of the control valves may prevent the release of air pressure during normal operation. Also, restrictions may slow the release of air pressure during normal operation.Performance Checks
If the Performance Checks indicate that the air pressure is not available at the air supply passage of the service brake control valve, loosen the connection at the air supply passage. Use soapy water to check for leaking air pressure.If the Performance Checks indicate leakage through the service brake control valve, disconnect the delivery hose at the end opposite the delivery passage. Place the end of the hose in a pan of water to check for leakage.Problem
The parking brake engages