Alignment Terminology; Front End Inspection; Front Wheel Camber - PREVOST H3-41 Maintenance Manual

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.
WARNING
During alignment, both camber and caster
among other angles are adjusted. When
adjusting these, we install or remove shims at
the IFS lower A-arms. After performing
alignment, make sure that the following is
done:
• Installing a new lock nut after all shims
are finalized.
• Torque replaced nuts as per Torque
Table.
• Installing a longer bolt if less than 2
threads are remaining after the nut.
• Using a torque seal, leave a mark on
the nut for future visual inspection.

16.1.1 Alignment Terminology

Wheel Camber: Camber is the number of
degrees the top of the wheel is tilted inward or
outward from a true vertical (Figure 45).
Wheel Toe-In: a slight forward convergence
given to the wheels of motor vehicles to improve
steering and equalize tire wear (D minus E,
Figure 45).
Kingpin Inclination: The inclination of the kingpin
from vertical toward the center of the vehicle at
the top and outward at the bottom (B, Figure 45).
Front Axle Caster: The inclination of the kingpin
from vertical in the fore and aft direction (C,
Figure 45).

16.1.2 Front End Inspection

Before checking front end alignment, make the
following inspection:
1. Check that the vehicle is at normal ride
height (see paragraph 3.18 "Suspension
Height Adjustment"
Suspension).
in section 16
PA1621 Maintenance Manual All Series | Section revised June 2019
SECTION 14: STEERING
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 kingpins for looseness.
7. Check that the length of the torque rod is
21 17/64" (540 mm) and the length of the
relay rod is 23 19/64" (592 mm).

16.1.3 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 A-arm may be improperly shimmed.
FIGURE 41: SHIMS AT THE LOWER A-ARMS
Check kingpin inclination. If kingpin inclination is
incorrect, readjust the camber and check kingpin
inclination again.
NOTE
Camber is more important than kingpin
inclination, so adjust camber and verify kingpin
inclination.
Shim the lower A-arm to adjust camber (Figure
41). If the kingpin inclination is incorrect, the
wheel kingpin 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.
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