Pontiac Fiero 1988 Service Manual page 158

WHEEL ALIGNMENT 3A 1
SECTION 3A
W H E E L ALIGNMENT
CONTENTS
G e n e r a l D e s c r i p t i o n ...
3A-1
Alignment 3 A-1
Front 3A-1
Rear 3A-1
Alignment Requirements (Front and
Rear) ... 3A-1
Preliminary Checks (Front and Rear) 3 A-1
Camber Angle 3 A-2
Caster Angle 3 A-2
Toe Angle 3 A-2
O n - C a r S e r v i c e
3A-2
Front Camber /Caster 3 A-2
Front Toe-in 3A-4
Rear Camber... 3A-4
Rear Toe-in 3A-4
Alignment Specifications 3 A-5
GENERAL DESCRIPTION
ALIGNMENT
F r o n t
Front alignment refers to the angular relationship
between the front wheels, the front suspension
attaching parts and the ground. The angle of the
knuckle away from the vertical, the pointing in or
"toe-in" of the front wheels, the tilt of the front wheels
from vertical (when viewed from the front of the
vehicle) and the tilt of the suspension members from
vertical (when viewed from the side of the vehicle), all
these are involved in front alignment.
R e a r
Rear alignment refers to the angular relationship
between the rear wheels, the rear suspension attaching
parts and the ground. Camber and toe in are the only
adjustments required.
F r o n t a n d R e a r A l i g n m e n t R e q u i r e m e n t s
Satisfactory vehicle operation may occur over a
wide range of (wheel) alignment settings. Nevertheless,
should settings vary beyond certain tolerances,
readjustment of alignment is advisable. The
specifications stated in column 2 of the applicable
vehicle chart in the specifications section of this
manual should be used by owners, dealers and
repairmen as guidelines in vehicle diagnosis either for
repairs under the new vehicle warranty or for
maintenance service at customer's request. These
specifications provide an acceptable all-around range
in that they prevent abnormal tire wear caused by
improper wheel alignment.
Governmental Periodic Motor Vehicle
Inspection programs usually include wheel alignment
among items that are inspected. To provide useful
information for such inspections, the specifications
stated in column 2 of the aforesaid applicable chart are
given and these are well within the range of safe vehicle
operation.
In the event the actual settings are beyond the
specifications set forth in column 2, or whenever for
other reasons the alignment is being reset, it is
recommended that the specifications given in column
3 of the applicable chart be used.
ALIGNMENT PRELIMINARY S T E P S
F r o n t a n d R e a r
The Pontiac Fiero is designed with independent
rear suspension that is service adjustable, making
four-wheel alignment possible. This is different from all
other Pontiac models, both FWD and RWD, which
have solid rear axles with fixed alignment.
Several different types of machines are available
for checking all the factors of front end alignment. The
alignment should be performed according to the
instructions that are furnished with each particular
machine. Adjustments should be made with the vehicle
level, and at curb weight.
Rear wheel alignment on Fiero can be performed
by backing the car onto a two-wheel aligner, or by
using the new, more efficient four-wheel aligners some
of which are illustrated in the GM dealer equipment
catalog. If the vehicle must be backed onto alignment
equipment and equipment does not compensate for
rear toe measurements, toe-in will read on the
equipment as toe-out.
Whenever a tire wear or handling condition is
encountered, rear alignment should be measured and
reset if necessary. Excessive toe-in or toe-out can cause
irregular or premature wear. For best tire wear, toe-in
should always be set to the low end of the specification.
Since steering complaints are not always the
result of improper alignment, a check should be made
to see if any of the following conditions exist. Any such
conditions should be corrected before proceeding
further.
1. Steering gear loose or improperly adjusted.
2. Steering gear housing loose at frame.
3. Excessive wear or play in spherical joints.
4. Tie rod, toe links or steering connections loose.
5. Improper front spring heights, or improper
operation of struts.
6. Unbalanced or underinflated tires.