TM 9-2330-294-14
torque applied. Apply full weight to wrench
CAUTION
handle and bear down hard to obtain proper
The cap nuts should be retightened with a
torque. If possible use a support under the
torque wrench as soon as the trailer returns
wrench at the handle end during tightening.
to organizational maintenance.
(9) Lower jack, if used, or lower axles by
(8) Alternately tighten each wheel nut slightly
releasing air pressure from air springs or air axle
until nut flange is against wheel face. Use tightening
lifts.
sequence shown in figure 2-22 to tighten wheel nuts
(10) Install the spare wheel and tire assembly on
as near as possible to 575-600 pound foot torque.
the spare tire carrier (para 2-25). Stow jack in towing
NOTE
vehicle.
A rule of thumb used to determine torque
(11) After approximately 25 to 50 miles of
application without using a torque wrench is
semitrailer operation with payload, retighten wheel
as follows: A man's weight times the number
nuts.
of feet of leverage equals the pound foot
Section II. OPERATION UNDER UNUSUAL CONDITIONS
on driving hazards in snow, ice, and unusual terrain
2-27. General
encountered under extreme cold-weather conditions.
a. It is imperative that the approved practices and
b. At-Halt or Parking.
precautions be followed. A detailed study of TM 21-
(1) When halted for short shutdown periods,
300 and FM 21-305 is essential for use of this
park the semitrailer in a sheltered spot out of the
materiel under unusual conditions. The M747
wind. For long shutdown periods, if high, dry
semitrailer has mobility to make short trips off-road
ground is not available, prepare a footing of planks
to reach vehicle collecting points, areas for con-
or brush.
cealment, and to detour around road obstructions.
(2) Clean all parts of the semitrailer of snow, ice,
b. For description of operations in extreme cold,
and mud as soon as possible after operation. Cover
refer to TM 9-207.
and shield the semitrailer but keep the ends of
c. Under sandy or dusty conditions, inspect, clean
canvas paulins off the ground to prevent them from
and lubricate parts more frequently than stated on
freezing to the ground.
lubrication charts.
d. When chronic failure of equipment results from
subjection to extreme conditions, report of the
a. Do not park the semitrailer in the sun for long
condition should be made, on DA Form 2407,
periods, as the heat and sunlight will shorten the life
Equipment Improvement Recommendation, and
of the tires. When practical, park semitrailer under
Standard Form 368, Quality Deficiency Report in
cover for protection from the sun, sand, and dust.
accordance with TM 38-750.
b. Equipment that is inactive for long periods in
hot, humid weather is subject to rapid rusting and
a. General.
accumulation of fungus growth. Make frequent
(1) The driver or operator must always be on the
inspections and clean and lubricate to prevent ex-
alert for indications of the effect of cold weather on
cessive deterioration.
the semitrailer.
c. Clean mildewed canvas straps and pamphlet
(2) The driver must be very cautious when
bag with a dry brush. Remove dirt with water only
placing the semitrailer in motion after a shutdown.
after mildew has been removed.
Congealed lubricants may cause failure of parts.
Tires frozen to the ground or frozen to the shape of
the flat spot while underinflated must be considered.
a. Mud. If one or more wheels become mired, it
One or more brake shoes may be frozen fast and
may be necessary to jack up the mired wheel and
require preheating to avoid damage. Rocking vehicle
insert planking or matting beneath it. If artillery
back and forth may shear ice if the brake shoes are
sleds are available install them under the wheels.
not badly frozen. Frozen lining can be prevented
b. Sand. Operation under sandy or dusty con-
after hosing vehicle down, operation on wet roads, or
ditions necessitates frequent inspection, cleaning,
after fording operations by lightly "riding" the
and lubrication of working parts.
brakes in travel for about mile; this action will
c. After-Operation Procedures.
Remove ac-
help dry out brakes before parking.
cumulations of ice, snow, and mud from the un-
(3) Refer to FM 21-305 for special instructions
derside of the semitrailer.
Change 1