TM 9-2330-294-14
(8) Tire iron (T45) must remain in place to hold
NOTE
second tire bead under flange (B, fig. 4-71 ). Raise
Failure to tighten cap nuts to proper torque
this tire iron slightly to assist placement of other tire
will result in fatigue rupture of the wheel
irons when they are repositioned.
studs.
(9) Alternately remove tire irons (T46B and
Any time a wheel is removed and replaced, and after
T48A) and position 2 to 4 inches away and take
25 to 50 miles of operation, wheel cap nuts must be
another bite (C, fig. 4-71). Continue to lubricate bead
checked and tightened to proper torque using the
with rubber soap water.
method just described. If an outer cap nut is below
(10) Continue operation until half way around
400 lb ft, retorque each inner and outer cap nut, one
rim. Tire bead at iron (T45) will be pulled to tire rim.
at a time, to 575 - 600 lb ft.
Insert wood or metal block (1 x 1 x 6 in.) ad-
NOTE
jacent to iron (T45) between tire and rim to hold tire
If wheels are not raised off ground, loosen
bead in position to enter groove in wheel rim (D, fig.
and retorque only one stud location at a
4-71) and remove iron (T45).
time.
(11) Use all three tire irons and continue forcing
g. Service Wheel Studs.
tire bead over flange until tire bead is completely
(1) Before operation and at each stop, inspect
secured by the flange. Remove irons and block.
for loose nuts, broken or missing studs. Broken
d. Inflate Tire. Stand tire upright and hold while
studs are a direct result of operating the semitrailer
applying air. Applying body weight to top of tire will
with loose cap nuts or improperly seated wheels.
usually seat tire beads and tire will inflate.
(2) Studs which have stripped threads, or are
CAUTION
bent or cracked must be replaced. Notify Direct
Excessive pressure will damage tire internal
Support personnel for replacement of fractured or
structure.
otherwise damaged studs.
If tire beads do not seat during inflation, put a bead
h. Measure Tire for Wear.
expander around outside center of tire to compress
(1) Measure tread depth of center groove at
tire and force beads to seat. If a bead expander is not
three points equally spaced around tire. If the
available, use load binder and chain. Apply only
average of these measurements is 3/32 inch or less,
enough pressure on tire to lightly seal beads against
replace tire.
rim. Inflate tire to 65 psi. Check tire beads on both
(2) Measure tread depth of side grooves at three
sides and make sure they are completely sealed
points equally spaced around tire. If the average of
against rim. Deflate tire and reinflate to remove
these measurements is 3/32 inch or less, replace-tire.
buildup of stresses in tire. Install cap on valve. If
tire is to be mounted as the inside dual, install valve
extension on tire valve. Apply rubber soap water
CAUTION
around rims and valve and check for leaks.
The fail-safe chamber power spring must be
e. Clean Wheel. Whenever a wheel is removed
manually compressed and the air reservoirs
from its hub, the hub face and mating wheel disc face
must be vented of pressure before removal of
must be wire brushed to bare metal before the wheel
hub and drum assembly.
is remounted. I n addition, the wheel studs, cap nuts
(1) Manually compress fail-safe chamber power
and wheel ball seats must be clean and undamaged.
Any worn cap nuts or damaged studs must be
(2) Vent air system pressure by venting air
replaced. If mounting face of wheel is not flat or ball
seats are damaged wheel is not to be put in service.
(3) Remove wheels in accordance with
NO OIL OR GREASE IS ALLOWABLE ON CAP
NUTS, STUDS OR BALL SEATS OF WHEEL.
(4) Remove six screws and lock washers
f. Torque Tighten Wheel Nuts ( f i g . 2 - 2 2 ) .
securing hub cap to hub and remove hub cap and hub
Semitrailers No. 1 through 200 have inner and outer
cap gasket. Discard gasket.
cap nut sets to secure the dual wheels. Torque nuts
(5) Remove wheel bearing jam nut using socket
socket (GGG-W-660) with torque wrench to tighten
(6) Remove pierced lock washer and remove
inner cap nuts to 575 - 600 lb ft. Then tighten outer
wheel bearing adjusting nut using socket (CPR
wheel cap nuts to 575 - 600 lb ft. Semitrailers No.
201 and on have only one set of cap nuts which
(7) Remove outer wheel bearing.
secures both wheels. Torque cap nuts to 575 - 600 lb
ft.