TM 9-2330-381-14
2-6.
HYDRAULIC CONTROLS AND ISOLATION VALVES (CONT)
CAUTION
Prior to making any gooseneck adjustments, the semitrailer must be uncoupled
and both the suspension shut-off valve and gooseneck isolation valve handles
pulled outward to the ADJUST position or damage to equipment may result.
GOOSENECK VALVE (5). A three-position hydraulic valve which is spring-loaded to the center (neutral) position and
used to provide hydraulic pressure for either raising or lowering the gooseneck. Semitrailer must be uncoupled and the
gooseneck isolation valve must be in ADJUST (pulled outboard) position to make adjustments Pull up to raise the
gooseneck, or push down to lower the gooseneck. This function will not operate correctly if the suspension shut-off valve
handle is pushed inward to the SHUT-OFF position.
CAUTION
After starting the AP and prior to making any platform or gooseneck adjustments
using the front curbside, front streetside, or rear or gooseneck valves, the
suspension shut-off valve handle must be pulled out to the ADJUST position or
unwanted movement and/or damage to equipment may result.
SUSPENSION SHUT-OFF VALVE (6). A series of ball valves which are used to shut off hydraulic power to the
semitrailer suspension. There are two positions for this valve handle: pushed inward is SHUT-OFF, and pulled outward
is ADJUST. When in SHUT-OFF position, the ball valves are closed and provide protection against unexpected
suspension and/or gooseneck movement. When in ADJUST position, the ball valves are open and normal suspension
and gooseneck adjustments can be made. The valve handle should be placed in the ADJUST position as soon as the
APU is started and prior to making any adjustments to the platform/gooseneck. This valve must be placed in SHUT-OFF
position for driving or parking/storage. If the semitrailer is to be parked/stored while uncoupled from a tractor, the
gooseneck must be completely lowered before moving this valve handle from ADJUST to SHUT-OFF position.
WARNING
Before operating gooseneck isolation valve, lower the front support legs. All
personnel must stand clear of the gooseneck or serious injury to personnel may
result.
CAUTION
Prior to making any gooseneck adjustments while uncoupled or in process of
coupling and/or uncoupling, the gooseneck isolation valve handle must be pulled
out to the ADJUST position. The gooseneck isolation valve must not be in the
ADJUST position when making suspension adjustments while coupled to a tractor
(i.e., loading and/or unloading procedures) or unwanted movement and/or damage
to equipment may result.
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