Before removing any air lines for
component maintenance, bleed the air
The governor, operating in conjunction with the
from the primary and secondary
compressor unloading mechanism, automatically
controls the air pressure in the system between the
desired, predetermined maximum and minimum
the engine runs, but the actual compression of air is
Perform the AIR SYSTEM TEST PRO-
controlled by the governor which stops or starts
CEDURE as the final step of ANY
compression when the maximum or minimum
reservoir pressures are reached. The governor has
functions are restored to full operational
a piston upon which air pressure acts to overcome
capability before returning the crane to
the pressure setting spring and control the inlet and
exhaust valve to either admit or exhaust air to or
from the compressor unloading mechanism.
Chock the wheels.
For more detailed information refer to the
Deplete all pressure in both systems.
applicable SM package.
Disconnect the air lines from the governor.
Remove the governor mounting bolts and
Chock the wheels.
remove the governor.
Deplete the air pressure in both air systems.
Open the engine compartment to gain access
Position the governor and secure it with the
to the compressor.
Drain the engine cooling system and the
Connect the air lines to the governor ports.
cylinder head of the compressor.
Tag and disconnect all air, water, and oil lines
going to and from the compressor.
Remove the two mounting nuts and remove
Start the vehicle engine and build up air
the compressor from the engine.
pressure in the system.
Check the pressure
registered by the dash gauge or a test gauge at the
time the governor cuts-out, stopping the
compression of air by the compressor.
secure it with the two mounting bolts.
Connect all air, water, and oil lines to the
proper fittings on the compressor.
Refill the engine cooling system.