TM 9-2330-271-14&P
(6) A right and left valve is used in the
suspension system. Both valves are linked to the rear
axle.
(7) The height control valves operate each
side independently, thus maintaining a side-to-side
semitrailer level condition at all times.
(8) The air suspension system is designed to
operate at a set ride height. The two height control
valves are used to maintain the proper axle-to-frame
relationship necessary to regulate ride height.
(9) Loss of air pressure or air spring
deflection by off center loading causes actuating arm to
move up.
(10) Up movement of actuating arm opens the
intake valve and allows supply air to pass through to the
air spring serviced by that valve.
(11) Down movement of actuating arm opens
the exhaust valve, allowing excess air pressure to vent to
the atmosphere.
(12) A check valve in the intake fitting prevents
pressure loss if high pressure air supply is interrupted.
(13) The height control valve incorporates a 5-
second time delay to prevent unnecessary actuation
while the vehicle is negotiating uneven terrain at
operating speeds.
(14) A 3/8-inch dead zone is built into the valve
Figure 4-42. . Ride height dimension adjustment, air
action to eliminate a valve hunting action.
suspension.
(15) Should an air spring fail, disconnect the
height control valve linkage on the inoperable side. Air to
(2) Position semitrailer on level ground,
the springs on that side will be shut off, allowing air
coupled to towing vehicle. Build up air pressure to 65 psi
pressure to build up in the system and in the air springs
and maintain this pressure while adjusting height control
on the opposite side.
valve.
(16) Rubber bumpers inside the air springs
(3) Disconnect linkage from both height
carry the loaded trailer should all springs go flat.
control valve actuating arms (fig. 4-42).
(17) Stability through the axle connections
(4) Move both actuating arms to a vertical
allows operation of a loaded trailer with pressurized
down position and hold until all air is exhausted from air
springs on one side of trailer only.
springs.
b. Adjustment of Air Suspension System.
(5) Connect one valve actuating arm only to
(1) Adjust height control valve for proper
its respective linkage. Air spring controlled by this valve
dimensions between axle centerline and underside of
will inflate until the valve shuts off inlet air pressure.
frame by setting one valve at a time (fig. 4-42).
(6) With the one set of air springs fully
inflated, measure distance from centerline of axle to
underside of frame (fig. 4-42).
4-61