TM 5-3810-305-23
0009
MALFUNCTION
Boom Extend Cylinder Binding.
CORRECTIVE ACTION
1.
Repair boom extend cylinder (WP 0150).
2.
Replace boom extend cylinder (WP 0150).
SYMPTOM
BOOM EXTEND CYLINDER EXTENDS BUT WILL NOT RETRACT
MALFUNCTION
Counterbalance Valve Malfunctioning.
CORRECTIVE ACTION
Replace counterbalance valve (WP 0150).
MALFUNCTION
Internal Leakage in Boom Extend Cylinder.
CORRECTIVE ACTION
1.
Reseal boom extend cylinder (WP 0150).
2.
Replace boom extend cylinder (WP 0150).
SYMPTOM
BOOM SECTION RETRACTS UNDER LOAD
MALFUNCTION
Boom Section Retracts Under Load.
CORRECTIVE ACTION
1.
With boom off to one side and horizontal, extend boom approximately 6 ft (1.83 m). Mark side of
the extended section at end of the boom base.
2.
Elevate boom to maximum angle and suspend a 5 ton (4.54 metric ton) load on a two-part line
1 ft (305 mm) off ground.
3.
With engine shut off, hold or tie boom extend lever in fully extended position for approximately
15 minutes.
4.
Return boom extend lever to neutral position. Start engine and lower boom to horizontal. Re-mark
extended section as in Step 1. Measure distance between marks. The difference is the leak-down:
Leak-down must not exceed 0.75 inch (19.1 mm) in 15 minutes with hydraulic oil at a working
temperature. If leak-down exceeds 0.75 inch (19.1 mm) in 15 minutes, perform Step 5.
0009-2
03/15/2011Rel(1.8)root(tswp)wpno(T00014)