Preventive Maintenance Procedures
Remove, disassemble, clean, and lubricate the
Chock the wheels.
Deplete all pressure in both air systems.
should be replaced.
Disconnect the two air lines from the pressure
Special attention should be given to the filter
when the maintenance check is made.
Remove the two mounting bolts, if used, and
remove the valve.
The filter must be clean and should be cleaned
or replaced if clogged or damaged.
Position the valve, and if used, install the
Under no conditions should the valve be
installed without a filter installed in the adapter.
Connect the two air lines to the proper ports of
Perform the procedures under Operating and
With the air system pressurized, make several foot
valve applications and note that each time an
application is made an exhaust of air occurs at the
exhaust port of the drain valve. If no air comes out,
push the wire stem. If no air comes out, the filter is
plugged and the valve should be removed and
If the pressure protection valve does not
operate as described or leakage is
Because the automatic drain valve
excessive, it is recommended that it be
functions as reservoir pressure is
reduced, excessive leakage in the
system could cause constant exhausting
Provide a pressure gauge and drain valve at
of the valve.
the supply side and delivery side of the pressure
protection valve being checked.
Build up the air system to full pressure and
With the system pressurized and pressure stabilized
shut off the engine.
in the system, there should be no leaks at the drain
valve exhaust. A constant slight exhaust of air at the
While watching the gauges on the supply and
drain valve exhaust could be caused by excessive
delivery sides of the valve, slowly begin to exhaust
leakage in the air system.
pressure from the delivery side. Note that both
gauges will show pressure loss until the closing
If the valve does not function as described or if
pressure of the pressure protection valve is reached.
leakage is excessive, it is recommended that the
The pressure protection valve should close at
valve be replaced or rebuilt. Refer to the Parts
approximately 85 5 psi (586 344 kPa). The gauge
on the delivery side of the valve should continue to
show loss of pressure while the gauge on the supply
side should stop at the same pressure as the setting
PRESSURE PROTECTION VALVES
of the valve.
For more detailed information refer to the
applicable SM package.