Section 16: SUPPLEMENT INFORMATION ON INDEPENDENT FRONT SUSPENSION (IFS)
16-21
4. FRONT END ALIGNMENT
Proper front end alignment must be main-
tained to insure ease of steering and provide
satisfactory tire life. When making front end
alignment inspections, the vehicle must be
level and empty with the full weight of the
vehicle on the wheels.
Front end alignment inspections fall into two
groups : regular service inspections per-
formed at periodic intervals, and inspections
to determine the extent of damage after a
collision or severe service.
Regular service inspections concern toe-in,
camber and caster. Any variation from the
specified alignment will indicate either a need
for adjustment or a more thorough inspection
to determine if parts replacement is required.
4.1 Definition Of Terms
4.1.1 Wheel Camber
The amount the wheels are inclined from the
vertical plane (A, Fig. 16).
4.1.2 Wheel Toe-In
The distance the front wheels are closer to-
gether at the front than at the rear of the tires
(D minus E, Fig. 16).
4.1.3 Front Axle Caster
The inclination of the king pin from vertical in
the fore and aft direction (C, Fig. 16).
4.1.4 King Pin Inclination
The inclination of the king pin from vertical
toward the center of the vehicle at the top and
outward at the bottom (B, Fig. 16).
4.2 Front End Inspection
Before checking front end alignment, make
the following inspection :
1.
Check that the vehicle is at normal ride
height (see paragraph "8. Suspension
Height Adjustment").
2.
Check the tires for proper inflation.
3.
Check wheel installation and run-out.
4.
Check wheel bearing adjustment.
5.
Check tie rods and drag link ends for
looseness.
6.
Check king pins for looseness.
7.
Check if the length of the torque rod is
23 9/64" (588 mm) (Fig. 15). Check if the
length of the relay rod is
22 13/32" (569 mm)
4.3 Front Wheel Camber
Positive camber is the outward inclination of
the wheels at the top, negative or reverse
camber is the inward inclination of the wheels
at the top. Camber variations may be caused
by wear at the wheel bearings, wheel spindle
bushings, or bent suspension parts.
Check camber, with an accurate gauge. If
camber is incorrect, check suspension parts
for wear and replace worn parts. If wear is not
perceptible, suspension parts may be bent or
lower suspension arm may be improperly
shimmed.
Check King pin inclination. If King pin inclina-
tion is incorrect, readjust the camber and
check king pin inclination again.
Note:
Camber is more important than king
pin inclination, so adjust camber and verify
king pin inclination.
When shimming the lower suspension arm,
an equal number of shims MUST be used at
each mounting bolt (Fig. 16). This allows the
proper clamp load to be maintained at each
bolt. If the king pin inclination is incorrect, the
wheel king pin assembly may be bent and
therefore should be replaced.
Excessive positive camber results in irregular
wear of the tires at the outer shoulders.
Negative or reverse camber causes wear at
the inner shoulders.
Note:
Shim only the lower suspension arm to
adjust the front wheel camber.
4.4 Front Wheel Toe-In
Toe-in is measured from the center of the tire
treads. Measurements at the front and rear of
the tires must be made at the same height
from the floor. Incorrect toe-in results in ex-
cessive tire wear and steering instability with
a tendency to wander.
