TM 5-5420-234-14&P
5-2. DIRECT SUPPORT TROUBLESHOOTING (continued).
4.
MAIN FRAME DOES NOT LOAD (continued).
MAIN FRAME LOAD 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 plug and O-ring from port TPMA
on main hydraulic block assembly.
(2) Install hose adapter, hose, and pressure
gage on main hydraulic block assembly.
(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 HOOK ARM ONLY
(manual mode) position.
(5) Attempt to load the main frame using the
remote control or cab controls.
CAUTION
Fully extending or retracting hydraulic
TEST
PORT
cylinders will put the hydraulic system
TPMA
into relief. This should be limited to
10 seconds. Failure to comply this
caution may result in damage to
equipment.
HOSE
NOTE
HOSE
ADAPTER
During an empty load cycle, the hy-
draulic pressure will read approximately
1,000 psi until the main frame hydraulic
cylinders are fully retracted. Full relief
pressure of 3,100 to 3,300 psi will be
reached at full retraction of the hydrau-
lic cylinder.
GAGE
(6) Observe the readings on the pressure
gage during loading.
(7) Shut off engine and turn off light control
switch.
(8) Remove hose adapter, hose, and pressure
gage from main hydraulic block assembly
(9) Install plug and O-ring in port TPMA on
main hydraulic block assembly.
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