MCi Crusader II 1989 Maintenance Manual page 22

Date
1-1-89
Page 1-16
MC-9 MAINTENANCE MANUAL
C. Axle caster: The fore and aft inclination from vertical of the
steering knuckle. "Positive caster .. is inclination of the top of the
steering knuckle towards the rear of the vehicle ... Negative
caster" is the inclination of the top of the steering knuckle
towards the front of the vehicle. "Zero" caster means no inclina-
tion of the steering knuckle.
D. King pin inclination: The amount king pins are inclined
mward at the top.
E. Steering geometry: The science of keeping the front
wheels in proper alignment during left or right turns.
CAMBER
Wheel camber is the tilting of the front wheels from .the
vertical center line. Outward inclination at top provides positive
camber and inward inclination provides negative camber.
Camber variations may be caused by wear at wheel bear-
ings and steering knuckle bushings or by bent knuckle or
sagging axle center.
Excessive positive camber results in irregular wear of tires at
outer shoulders. Negative or reverse camber causes wear at
inner shoulders. Ease of steering is also affected by any devia-
tion from specified camber.
Position front wheels on turning plates in a straight ahead
posItIor.. Attach alignment gauges to each wheel spindle.
Record the camber readings for each wheel and compare with
specifications. Refer to figure ,
-32
and Front Axle
Specifica-
tions Chart at the end of this section.
TOE-IN ADJUSTMENT
Wheel toe-in 1s the distance the front wheels an::i closer
together at the front than at the rear of axle.
Incorrect toe-in results in excessive tire wear caused by side
slippage. Unstable steering with a tendency to wander may also
result. The following steps are to check and ad1ust toe-in:
NO TE: Make sure vehicle is on a level floor.
Do not measure toe-in with the front axle jacked up. The
toe-in should be measured with the weight of the vehicle on the
axle.
i. Jack up the front axle.
2. Use paint or chalk and whiten the center area of both front
tires around the entire circumference.
3.
Position a scribe or pointed instrument against the whi-
tened part of each tire and rotate the tires. the scribe must be
held firmly in place so that a single straight line is scribed all the
way around the tire.
4. Place a full-floating turning radius gauge plate under
each wheel. Lower the vehicle and remove the lock pins from
the gauge plates. If full-floating turning radius gauge plates are
not available, lower the vehicle and move it backward and then
forward approximately
6
feet
(i
.8
m).
5. Position trammel bar at rear of tires and adjust pointers to
line up with scribe lines and lock in place (scale should be set
on zero). Pointers must be raised to spindle height on the tire as
shown (figure 1-31 ).
6.
Position the trammel bar at the front of the tires. Adjust
scale end so that pointers line up with scribe marks.
7. Read toe•m or toe-out from the scale. Scale should read
toe-in 11 i
6"
:!:
1116" (1.58 mm :!: 1.58
mm) (see figure i
-31 ).
8.
If adjustment is necessary, loosen the tie-rod clamps
and turn tie rod as required. then tighten the clamps.
If
the
vehicle is not on gauge plates. move it backward. then
forward about 6 feet (1.8 m).
9. Recheck the toe-in to ensure that It is-correct.
DLl□I I
,I I, I
!'
li't !,II
)I
:,JO
'-
l '-
~·
,~·
r·a,a;
...,... 1 .l
~
,,
" ' '
' t:
t1
r
1111
-
I .., t
I
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Figure 1-31. Trammel Bar With Pointers
Set At Spindle Height.
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