3-28
MECHANICAL ADJUSTMENTS
FASTENERS:
All fasteners in the IC-40 should be checked and retightened, if required, as a part of the
preventive maintenance program. Particular attention should be given to the axle, wheel
& hub mounting bolts, pump mounting bolts, rotation bearing bolts, rotation gearbox bolts,
and hoist bolts. All bolts used in assembly are heat-treated Grade 5, except the wheel
bolts and the bolts attaching the rotation bearing to the mainframe and turret, which are
Grade 8. Torque the rotation bearing mounting bolts to 200 ft-lbs (270 N-m). Torque the
wheel nuts to 500 ft-lbs (680 N-m). The torque chart on the next page can be used on all
other bolts.
ROTATION GEARBOX:
The rotation gearbox assembly is attached to the chassis top plate by four capscrews. It
is held in proper engagement with the external teeth on the bull gear by two jackscrews in
front of the gearbox. It is further restrained from torsional movement by four bolts at the
sides of the gearbox. Proper adjustment exists when there is .010-inch (.25 mm)
backlash between the pinion and bull gear teeth. If adjustment is required, loosen the
gearbox mounting bolts and the side bolts. Tighten the two front jackscrews until proper
adjustment is obtained. Tighten the mounting bolts and the side bolts. Lock jackscrews
and bolts into position.
WHEEL BEARING ADJUSTMENTS:
Wheel bearing adjustment must be maintained at all times. Adjustment is made each
time the bearings are repacked (annually). Wheel bearings are adjusted by the adjusting
nut. This nut should be tightened until only a slight drag is felt when rotating the wheel.
WHEEL ALIGNMENT:
Toe-in, which is the setting of the steering wheels so they are closer together at the front
than at the rear, is adjusted by lengthening or shortening the tie rods. Proper toe-in for
the rear wheels is zero.
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