Western Star 47X 2020, Maintenance Manual

Page: 87 / 166

Weak or broken leaf springs, or worn shackle
bushings, can cause extreme deviations to
caster angles. Replace damaged parts before
doing caster adjustments.
1. Apply the parking brakes, and chock the front
and rear tires.
2. Back off the U-bolt nuts from the U-bolts on one
side of the front axle. See
Fig. 13 .
3. Raise the spring away from the axle enough to
allow removal of the front caster shim.
4. Remove the shim, and install one that will pro-
vide the correct caster angle, as specified in the
table in Alignment Specifications in this section.
Install the dowel pin and check penetration.
IMPORTANT: Place front caster shims between
the axle beam and the axle spacer, or between
the axle beam and the shock absorber bracket.
See
Fig. 13.
5. Lower the vehicle onto the axle.
6. Coat the threaded ends of the U-bolts with chas-
sis lube or an antiseize compound, such as Loc-
tite® 242. Tighten the U-bolt nuts to the value in
the appropriate table in
Group 32 of the Western
Star 47X and 49X Workshop Manual for com-
plete procedure.
U-bolt nuts need periodic retightening. Refer to
Group 32 of this manual for recommended inter-
vals.
CAUTION
Failure to periodically retighten the U-bolt nuts
could result in spring breakage and abnormal tire
wear.
7. Using the steps above, replace the shim on the
other side of the axle.
8. Do a final caster angle check.
Wheel Toe-In Adjusting, Integral
Gear Steering
1. Loosen the tie rod (cross tube) clamp nuts, and
turn the tie rod as needed.
If the vehicle is not on turn-plates or turntables,
move the vehicle backward and then forward
about six feet (two meters) — this is important
when setting the toe-in on vehicles equipped with
radial tires. Apply the parking brakes and chock
the rear tires.
Do a final wheel toe-in check to make sure that it
is correct.
f400096a 10/21/2016
1
A
B
C
A. Positive Caster
B. Zero Caster
C. Negative Caster
1.
Knuckle Pin (Kingpin)
Fig. 12, Caster Angle
Front Axle
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