TM 5-5420-234-14&P
5-2. DIRECT SUPPORT TROUBLESHOOTING (continued).
1.
HOOK ARM DOES NOT UNLOAD (continued).
HOOK ARM
CYLINDER
MANIFOLD
COUNTERBALANCE VALVE TEST
(1)
Remove left hook arm cylinder
manifold from cylinder (para 5-23).
(2) Remove counterbalance valve from
manifold port VA.
(3) Remove counterbalance valve from
manifold port VB and install in port
PORT VA
VA.
(4) Install remaining counterbalance
valve in manifold port VB.
PORT VB
(5) Install left hook arm cylinder
manifold on cylinder (para 5-23).
(6) Start engine and engage the PTO.
(7) Turn the light control switch to the
ON position. Place LHS MODE
SELECT switch in the HOOK ARM
ONLY (manual mode) position.
(8) Attempt to unload the hook arm
using the remote control or cab
controls. Note the operation of the
hook arm.
(9) Shut off engine and turn light control
COUNTERBALANCE
switch to OFF position.
VALVE
(10) If the hook arm now unloads
properly, the counterbalance valve
installed in the left manifold port VB
is faulty. If the hook arm still does
not unload, the counterbalance valve
in the right manifold port VA is
faulty.
5-9
