10. Warning buzzer and light will operate until both
pressure gauge needles show 60 - 70 psi.
Perform the AIR SYSTEM TEST
PROCEDURE as the final step of ANY
Release park brakes.
functions are restored to full operational
12. Continue charging air system until air dryer
capability before returning the crane to
cycles and compressor shuts off, all system gauges
should read 120 10 psi.
Turn off engine.
AIR SYSTEM TEST PROCEDURE
Check that all wheels turn freely.
15. Air pressure should remain constant with no
Refer to the Air System Components
leaks. Any drop in pressure should be no more than
Location Table, and the Figure titled Air
1 psi per minute.
System Component Locations
16. Apply service brakes to full application and
Perform a test of the complete Air System.
Accomplish all tests in sequence as defined below:
17. Check that a drop in reservoir pressure
Park crane on a firm level surface.
pressure loss does not exceed 2 psi per minute.
Raise crane on outriggers.
Check that brakes are applied on all wheels,
Turn off engine.
19. Release the service brake and check that
existing reservoir pressure is maintained.
Drain entire system by opening drain cocks on
the air reservoirs.
Start engine and recharge air system.
If not already on, park brakes will automatically
21. With engine running, simulate a full air leak in
apply with air pressure drop.
the secondary air system by opening the drain cock
on the secondary air reservoir.
Check that brakes are applied on all wheels.
22. The low air pressure light and warning buzzer
Close drain cocks and start engine.
should come on when the air pressure in the
secondary system drops below 70 5 psi.
Low Air Pressure light and warning buzzer
should operate immediately.
23. Air pressure in the primary system should not
drop below 85 5 psi.
Air will fill the main supply reservoir first,
consequently, the red needle on the dual air gauge
Drain secondary air system pressure to 0 psi.
will rise first, pressure will increase to approximately
85 psi, at which time the pressure protection valve
25. With park brakes released, check that all
will open, allowing air to flow into the secondary air
wheels can turn.
reservoir and the green needle will then begin to rise.
Apply service brakes and hold.
27. Front service brakes and rear spring brakes
If required, the pressure protection valve
pressure setting can be adjusted by
turning the cap; Clockwise to raise the
28. Assure brake lights on rear of machine come
pressure - Counterclockwise to lower the
on when service brakes are applied.
Release service brakes.