TM 5-3810-307-24-1-2
Page
No.
INTRODUCTION ............................................................................................................................
TROUBLESHOOTING....................................................................................................................
MAINTENANCE..............................................................................................................................
Head Assembly Replacement.............................................................................................
Rear Seal and Adapter Replacement .................................................................................
Piston Assembly Replacement ...........................................................................................
Connecting Rod Assembly Replacement............................................................................
Crankshaft Bearing Replacement .......................................................................................
I-1.
INTRODUCTION
The air compressor is an engine-driven, piston-type compressor which supplies compressed air to
operate air-powered devices. The compressor runs continuously but has loaded and unloaded
operating modes. The operating mode is controlled by a pressure-activated governor and the
compressor unloading assembly. When the air system reaches cut-out pressure, the governor applies
an air signal to the air compressor unloader assembly causing the unloader cap valve to activate and
stop compressed air from flowing into the air system. As the air in the air system is used, the pressure
drops. At cut-in pressure, the governor exhausts the air signal to the compressor unloader assembly,
allowing the compressor to again pump compressed air into the air system.
I-2.
TROUBLESHOOTING
NOTE
The following air compressor troubleshooting assumes that the crane's air
system is otherwise operating properly e.g., the governor is operating;
exhaust line is not blocked, frozen, or leaking; air dryer, reservoirs, and
piping are functional.
SYMPTOM
PROBABLE CAUSE
CORRECTIVE ACTION
1. Compressor will not pump
a. Unloader valve stuck open.
a. Replace head assembly.
air.
b.
Inlet valve broken.
b.
Replace head assembly.
c.
Exhaust valve broken.
c.
Replace head assembly.
d.
Exhaust valve wedged open.
d.
Replace head assembly.
e.
Internal relief valve broken.
e.
Replace head assembly.
2. Compressor slow to build air.
a.
Air intake valve leaks.
a.
Replace head assembly.
b.
Exhaust valve leaks.
b.
Replace head assembly.
c.
Excessive piston ring wear.
c.
Replace piston assembly.
d.
Head gasket leaks.
d.
Replace piston assembly.
e.
Internal relief valve leaks.
e.
Replace head assembly.
3. Compressor exceeds cut-out
a.
Unloader failure.
a.
Replace head assembly.
pressure.
Change-1 I-3
