1988 PONTIAC FIERO Service Repair Manual

3D-4 REAR SUSPENSION
Fig. 604 Track Bar arrd Track Bar Brace
4. Heat shield screws to track bar brace.
5. Remove rear axle support and lower car.
REAR LOWER CONTROL ARM
Fig. 605
NOTICE: If both control arms are being replaced,
remove and replace one control arm at a time to
prevent the axle from rolling or slipping sideways
making replacement difficult.
Remove or Disconnect
1. Hoist car and support rear axle at curb height
position.
2. Lower control arm to axle housing bolt and
control arm to underbody bolt.
3. Control arm.
Install or Connect
NOTICE:
See NOTICE on Page 3D-1 of this
section.
1. Position control arm and install front and rear
nuts and bolts.
2. Torque front and rear bolts.
3. Rear axle support and lower car.
BUSHING (REAR LOWER CONTROL ARM)
Fig. 606 and 607
Remove or Disconnect
1. Control arm as specified in Rear Lower Control
Arm Removal Procedure.
2. Place receiver 5-25317-2 over flanged side of
bushing.
3. Use an arbor press to force the bushing out of the
arm, using large
O.D. of a driver such as
J-21465-8 contacting O.D. of bushing outer
sleeve.
Install or Connect
NOTICE:
See NOTICE on Page 3D-1 of this
section.

REAR SUSPENSION 3D-5
FRONT OF LOWER CONTROL ARM REAR OF
LOWER CONTROL ARM (R.W. SHOWN L.H. OPPOSITE) (R.H. SHOWN L.H. OPPOSITE)
1. UNDERBODY PAN ASSEMBLY 4. 108 N.rn (80 LBS. FT.)
2. LOWER CONTROL ARM BODY BRACKET 5. AXLE ASSEMBLY
3. UNDERBODY ROCKER PANEL SHEET METAL
Fig.
605 Rear Lower Control Arm
1. PRESS 2. J 22222-5
3.
J 25317-2
4.
J 21465-8
Fig. 606 Removing Bushing; Control Arm
To install the bushing, reverse the tool as shown
in Fig.
607 and push bushing into position. Connect the
rear control arms as outlined in Rear Lower Control
Arm Installation procedure.
TORQUE ARM
Fig. 608 and 609
NOTICE: Coil springs must be removed before
removing torque arm to avoid rear axle forward
twist which may cause axle to shift position and
damage vehicle.
1. PRESS
2. J 25317-2
3.
J 22222-5
4.
J 25317-1
I I Fig. 607 Installing Bushing; Contrcl Arm
Remove or Disconnect
1. Hoist car on a non twin post-type hoist and
support rear axle assembly with an adjustable
lifting device.
2. Track bar mounting bolt at axle assembly and
loosen track bar bolt at body brace.
3. Rear brake hose clip at underbody to allow
additional axle drop.
4. Right and left shock absorber lower attaching
nuts.
5. Carefully lower rear axle. Remove coil springs.
NOTICE: DO NOT suspend rear axle by brake
hose. Damage to hose could result.

30-8 WEAR SUSPENSION
WITH 700 R4 TRANSMISSION
1-41 Nern (30 FT.
LB.)
2-41 Nern (30 FT. LB.)
3-TORQUE ARM
4-27 Nern
(20 FT. LB.)
5-CONVERTER HANGER
6-TORQUE 135
Nern (100 FT. LB.)
Fig. 608 Torque Arm Attachment; Auto. Trans.
6. Torque arm rear attaching bolts. 5. Shocks to rear axle. Toique nuts.
7. Front torque arm outer bracket and remove
6. Thoroughly clean track bar to axle assembly bolt
torque arm. and nut
as outlined under Recommendations for
Reuse of Prevailing Torque Fasteners in Section
Install or Connect OA.
7. Brake line clip to underbody. On Page 3D-1 of this 8. Remove adjustable lifting device and lower car.
section.
1. Position torque arm and loosely install rear
torque arm bolts.
2. Install front torque arm bracket and torque nuts
to 27
N.m (20 1b.ft.) specifications as outlined in
Figs.
608 and 609.
3.
Torque rear torque arm nuts.
4. Position springs and insulators in spring seats and
raise rear axle until rear axle supports weight of
vehicle at normal curb height position.
REAR STABILIZER SHAFT
NOTICE: See NOTICE on Page 3D-1 of this
section.
The rear stabilizer shaft is available on some
models and attaches as shown in Fig.
610.
BUMPER (RUBBER)
The rear axle bumper is located on the top of the
axle housing as shown in Fig.
61 1.

REAR SUSPENSION 3D-7
1. 41 N-rn (30 LBS. FT.)
2. TRANSMISSION
3. BRACKET
4. TORQUE ARM
5. CONVERTER HANGER
Fig. 609 Torque Arm Attachment, Manual Trans.

3D-8 REAR SUSPENSION
TYPICAL BUMPER INSTALLATION
1-LONGITUDINAL REINFORCEMENT
2-WELD NUTS
3-27NM (20
FT.LB.1
4-AXLE ASM.
5-JOUNCE STOP REINF.
Fig. 6 1 1 Rubber Bumper Assembly
Leakage Diagnosis
The appearance of oil film on the shock absorber body or
piston rod
is normal. Any dripping of oil is unacceptable.
I OIL FILM OK I
ANY OIL DROP
IS UNACCEPTABLE
I Disposal I Due to the high pressure of gas it is advised that, upon
scraping or disposal of these shock absorbers, the pres-
sure be released. This
is carried out as follows:
a. Clamp shock in vise with piston rod pointing down.
b. Measure approx. 10-15 mm (0.5 in.) from bottom of
shock and drill an approx. 5
mm hole so the gas can
escape.
c. Measure approx. 140-150
mm (5.5-6.0 in.) from first hole
and drill an approx. 5
mm hole to facilitate drainage of
oil.
d. Drain oil'from shock and then dispose of shock.
BOTTOM
DRILL THlS HOLE FIRST
140-150 rnrn (5.5-6.0 in.)
DRILL THlS HOLE LAST
DUE TO EXPLOSION
UNDER
HIGH DO NOT APPLY
HEAT OR FIRE
Fig. 612 Gas Shock

REAR SUSPENSION 3D-9
"Torque Specifications
................................................ Nut. Shock Absorber to Upper Mount 17 N.m (150 1b.in.)
............................................................ Nut. Shock Absorber to Axle 95 N-m (70 1b.ft.) .................................................................. Bolt. Track Bar to Axle 80 N.m (59 1b.ft.)
....................................................... Nut. Track Bar to Body Bracket 105 N-m (78 1b.ft.)
............................................... Nut. Track Bar Brace to Body Bracket 105 N-m (78 1b.ft.)
Screws. Track Bar Brace to Body ............................................................................ Brace Bracket 47 N.m (34 1b.ft.)
....................................................... Bolt. Control Arm to Rear Axle 108 N-m (80 1b.ft.)
...................................................... Bolt. Control Arm to Underbody 108 N.m (80 1b.ft.)
........................................................ Bolt. Torque Arm Outer Bracket 42 N.m (31 1b.ft.)
Nut. Torque Arm to Rear Axle ............................................................................. Differential 135 N-m (100 1b.ft.)
Bolt. Stabilizer Shaft to Body
Bracket
.................................................................................... 22 N.m (16 1b.ft.)
Screw. Stabilizer Bracket ................................................................................... to Body 47 Nam (35 1b.ft.l
Nut. Stabilizer Shaft Clamp ................................................................................. to U-Bolt 27 N-m (20 1b.ft.)
Bolt. Axle Bumper Bracket ............................................................................ to Underbody 27 N-m (20 1b.ft.)

TIRES AND WHEELS 3E-1
RES AND WHEELS
NOTICE: All wheel bolt and nut fasteners are important attaching parts in that they could affect the
performance of vital components and systems, and/or could result in major repair expense. They must be replaced
with one of the same part number or with an equivalent part if replacement becomes necessary. Do not use a
replacement part of lesser quality or substitute design. Torque values must be used as specified during reassembly
to assure proper retention of parts.
CONTENTS
Diagnosis ............................................... Section 3 Tire Repair ................................................... 3E-5
General Information .......................... ..... 3E-1 Waddle ........................................................ 3E-5
........ Replacement Tires ....................... ... 3E- 1 Measuring Wheel Runout ............................ 3E-6
P-Metric Tires ...................... .. ................... 3E-2 Spare Tire ...................................................... 3E-6 ................................................ Tire Placard 3E-2 Match Mounting ......................................... 3E-7
.......................................................... Wheels 3E-2 Balancing Tire and Wheel ............................ 3E-7
....................... Maintenance and Adjustments .............. 3E-2 General Balance Precautions 3E-7 ...................................... Wheel Repair .............................................. 3E-2 Off-Car Balancing 3E-8 .............................. Metric Wheel Nuts and Studs .................... .. 3E-3 On-Car Balancing .. ...... 3E-8
......................................... Inflation of Tires ........................................ 3E-3 Wheel Weights 3E-8 .................... Tire Rotation ........................... ...... . 3E-3 Correcting Non-Uniform Tires 3E-8 .......................... Tire Chain Usage ........................................ 3E-4 Aluminum Wheel Cleaning 3E-9 Aluminum Wheel Hub Cap ......................... 3E-9 Service Operations ..................................... 3E-4 Aluminum Wheel Porosity Repair .............. 3E-9 ......................... Wheel Removal .... .......... 3E-4 Aluminum Wheel Refinishing ...................... 3E-9 Tire Mounting and Dismounting ................. 3E-5 Wheel Nut Torque 3E-10 ......................................
GENERAL INFORMATION ~t is recommended that new tires be installed in
pairs on the same axle. If it is necessary to replace only
The tires and are one tire, it should be paired with the tire having the
designed to operate satisfactorily with loads up to and
most tread, to equalize braking traction. including the full rated load capacity when inflated to
Although they may appear different in tread
the recommended inflation pressures.
design, tires built by different manufacturers with
Correct tire pressures, wheel alignment and identical TPC specification numbers, can be
driving techniques have an important influence on tire
intermixed on the same car. life. Heavy cornering, excessive rapid acceleration, and
heavy braking will increase tire wear.
REPLACEMENT TIRES
Fig. 1
A Tire Performance Criteria (TPC) specification
number is molded in the sidewall near the tire size of
all original equipment tires. This specification number
assures that the tire meets
GM's performance
standards for traction, endurance, dimensions, noise,
handling, rolling resistance, and others. Usually, a
specific TPC number is assigned to each tire size.
When replacing tires, only the size, load range,
and construction as originally on the car are
recommended. This can best be accomplished by
replacing with tires of the same TPC specification
number. Use of any other tire size or construction type
may seriously affect ride, handling,
speedometer/odometer calibration, car ground
clearance and tire clearance to the body and chassis.
This does not apply to the spare furnished with the car.
v// TIRE IDENTIFICATION
Fig. 1 Tire Identification