The air dryer consists of a desiccant cartridge and
With the engine still running, perform a series
a die cast aluminum end cover secured to a
of brake applications to reduce the air pressure and
cylindrical steel outer shell with eight capscrews
observe the pressure when the governor cuts-in the
and nuts. The end cover contains a check valve
assembly, a safety valve, three threaded air
kPa) Never adjust the governor pressure settings
connections and the purge valve housing
unless they are checked with a gauge that is known
assembly. The removable purge valve housing
to be accurate If it has been determined that the
assembly incorporates a purge valve mechanism
pressure settings of the governor must be changed,
and a turbo charger cutoff feature that is designed
the procedure is as follows:
to prevent loss of engine turbo boost pressure
during the purge cycle of the air dryer. For ease of
Unscrew the cover at the top of the
serviceability, the desiccant cartridge and
discharge check valve assembly are screw-in type.
The purge valve housing assembly, which includes
the heater and thermostat assembly, and the
Loosen the adjusting screw locknut.
discharge check valve assembly, is serviceable
from the exterior of the air dryer, while servicing the
Turn the adjusting screw counter-
screw-in desiccant cartridge requires removal of
clockwise to raise the pressure settings and
the air dryer assembly from the crane.
clockwise to lower the pressure setting.
Tighten the adjusting screw locknut to
lock the adjustment.
Chock the wheels.
Repeat Step 2 as necessary.
Deplete the pressure in both air systems.
Ensure the ignition switch is in the OFF
Leakage checks on the governor are made at
its exhaust port in both the cut-in and cut-out
Tag and disconnect the air lines from the
positions. In the cut-in position, check the exhaust
port for inlet valve leakage by applying a soap
solution at the port. Leakage could also be through
Disconnect the electrical lead from the bottom
the bottom piston grommet. In the cut-out position,
of the dryer.
check the exhaust port to determine leakage at the
exhaust valve seat or stem grommet. In this
position, leakage could also be through the upper
attaching the dryer to the chassis frame and remove
If the governor does not function as described,
If the dryer is to be replaced with a new one,
or if leakage is excessive, it is recommended that it
remove the fittings from the dryer ports.
be repaired or replaced. Refer to the Parts Manual.
The dryer does not have to be removed
to disassemble it.
The function of the air dryer is to collect and
remove air system contaminates in solid, liquid, and
Install the fittings in the dryer ports.
vapor form before they enter the brake system. It
provides clean, dry air to the components of the
Position the air dryer on the mounting bracket
brake system which increases the life of the system
and reduces maintenance costs.
Connect the electrical lead to the connection
on the bottom of the dryer.