TM 5-5420-234-14&P
5-2. DIRECT SUPPORT TROUBLESHOOTING (continued).
1.
HOOK ARM DOES NOT UNLOAD (continued).
HOOK ARM UNLOAD PRESSURE TEST
WARNING
The LHS hydraulic system operates at oil
pressures up to 3,625 psi (24,994 kPa).
Never disconnect any hydraulic line or
fitting without first dropping pressure to
zero. Failure to comply with this warning
may result in serious injury or death to
personnel.
(1) Remove hose no. 2892 from fitting at rear of
main frame.
(2) Install tee fitting, hose adapter, hose, and
pressure gage between fitting and hose no.
2892.
(3) Start engine and engage the PTO.
(4) Turn the light control switch to the STOP
LIGHT position. Place LHS MODE SELECT
switch in the manual HOOK ARM ONLY
(manual mode) position.
(5) Attempt to unload the hook arm using the
remote control or cab controls.
CAUTION
TEE
FITTING
Fully extending or retracting hydraulic
cylinders will put the hydraulic system
HOSE
FITTING
into relief. This should be limited to 10
ADAPTER
seconds. Failure to comply with this
caution may result in damage to
equipment.
HOSE
NOTE
During an empty unload cycle, the hydraulic
pressure will read approximately 1,000 psi
until the hook arm hydraulic cylinders are
~
fully extended. Full relief pressure of 3,100
to 3,300 psi will be reached at full extension
of the hydraulic cylinder.
(6) Observe the readings on the pressure gage
HOSE
during unloading.
NO. 2892
(7) Shut off engine and turn off light control
switch.
PRESSURE
(8) Remove tee fitting, hose adapter, hose, and
GAGE
pressure gage from between fitting and hose
no. 2892.
(9) Install hose no. 2892 on fitting at rear of main
frame.
5-7
