PONTIAC FIERO 1988 Service Repair Manual

3C-18 FRONT SUSPENSION
1-SIDE RAIL
2-CROSSMEMBER 3-WASH E
R
4-BOLT (105 Nwm)
5-LOCATING PIN
I I Fig. 6 10 Front Suspension Crossmember
SPEGIFICA"T0NS
Strut Aarembly Stmt-to-Knuckle Bolts
Strut-to-Upper Mount Nut
Upper Mount-to-Wheelhouse Tower
Lower Contrd Arm
Pivot
Rolt Nuts
Bumper-to-LCA
LCA Ball Joint-to-Knuckle
Knuckle Strut-to-Knuckle Bolts
LCA Ball Joint-to-Knuckle
Ft. Lbs.
Fig.
6 1 1 Specifications

REAR SUSPENSION 30.1
SECTION 3D
REAR SUSPENS
NOTICE: All rear suspension fasteners are important attaching parts in that they could affect the
performance of vital parts 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 all parts. There is to be no welding as it may result in extensive damage and weakening
of the metal.
CONTENTS
General Information ................................ 3D- 1 Rear Lower Control Arm ............................ 3D-4
Qn-Car Service ............................ .. .......... 3D- 1 Bushing (Rear Lower Control Arm) ........... 3D-4
Shock Absorbers ........................................ 3D- 1 Torque Arm .............................................. 3D-5
Coil Springs and Insulators ......................... 3D- 1 Rear Stabilizer Shaft .................................. 3D-6
Track Bar ................................................... 3D-3 Bumper (Rubber) ....................................... 3D-6
Track Bar Brace ................... .. ................. 3D-3 Torque Specifications .................................. 3D-9
GENERAL INFORMATION
The rear axle assembly is attached to the vehicle
through a link type suspension system. The axle
housing is connected to the body by two lower control
arms and a track bar. A single torque arm is used in
place of upper control arms. It is rigidly mounted to the
rear axle housing at the rear and through a rubber
bushing to the transmission at the front. Coil springs
are used to support the weight of the car, and ride
control is provided by shock absorbers mounted to the
rear of the axle housing. A stabilizer shaft is optional.
The shock absorbers are mounted at the bottom
with a bolt and nut to brackets welded to the axle
housing, and at the top to the reinforced body area with
a nut. The only service the shock absorbers require is
replacement if they
have lost tllcir resistance, are
danaged, or are leaking flldd.
ON-CAR SERVICE
SI-IOCK ABSORBERS
Fig. 602
Remove or Disconnect
1. Hoist car and support rear axle.
2. From above, pull back carpeting and remove
shock absorber upper mounting nut.
NOTICE: Axle assembly must be supported
before removing upper shock absorber nut to avoid
possible damage to brake lines, track bar and prop
shaft.
3. Loosen and remove shock absorber lower
mounting nut from shock absorber. Remove
shock.
Install or Connect
NOTICE: See NOTICE on Page 3D-1 of this
section.
1. Position shock absorber through body mounting
hole and loosely install the lower shock absorber
mounting nut.
2. From above, install the upper shock absorber
retainer and nut. Torque nut.
3. Torque lower shock absorber nut.
4. Remove rear axle support and lower car.
COIL SPRINGS AND INSULATORS
Fig. 603
Remove or Disconnect
1. Hoist car on non twin post-type hoist and support
rear axle assembly with an adjustable lifting
device.
2. Track bar mounting bolt at axle assembly.
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 and remove spring(s)
and or insulator(s).
NOTICE: DO NOT suspend rear axle by brake
hose. Damage to hose could result.
Install or Connect
NOTICE: See NOTICE on Page 3D-1 of this
section.

3D-2 REAR SUSPENSION
1. RAIL
2. JOUNCE BUMPER
3. SPRING INSULATOR ASSEMBLY
4, COIL SPRING
5. OPTIONAL STABILIZER BAR
6. LOWER CONTROL ARM
7. UNDERBODY
8. TORQUE ARM
9. PROP SHAFT
10. SHOCK ABSORBER
11. TRACK BAR
12. TRACK BAR BRACE
Fig.
60 1 Rear Axle and Suspension Assembly

REAR SUSPENSION 30-3
1. Position springs and insulators in spring seats and
raise rear axle until rear axle supports weight of
vehicle at normal curb height position.
2. Shocks to rear axle. Torque nuts. 1-17 N.M (13 FT.LB.1 3. Thoroughly clean track bar-to-axle assembly bolt
2-UNDERBODY and nut as outlined under Recommendation for
Reuse of Prevailing Torque Fasteners in Section
3-95 NeM (70 FT.LB.) 4. Track bar mounting bolt at axle and torque nut.
4-AXLE ASM. Torque track bar to body bracket nut.
5. Brake line clip to underbody.
6. Remove adjustable lifting device from beneath
axle and lower car.
TYPICAL SHOCK INSTALLATION TRACK BAR (RH SHOWN)
Remove or Disconnect
at body bracket.
3. Track bar.
Install or Connect
NOTICE: See NOTICE on Page 3D-1 of this
1. Position track bar in body bracket and loosely
install bolt and nut.
2. Thoroughly clean track bar to axle assembly bolt
and nut as outlined under Recommendations for
Reuse of Prevailing Torque Fasteners in Section
3. Position track bar at axle. Install bolt and nut.
4. Torque track bar nut at body bracket to 78 Nem
5. Remove rear axle support and lower car.
TRACK BAR BRACE
1. Hoist car and support rear axle.
2. Heat shield screws from track bar brace.
3. Three track bar brace to body brace screws.
4. Nut and bolt at body bracket. Remove track bar 1-REAR UNDERBODY SHOCK TOWER
AND SPRING SEAT.
2-SPRING INSULATOR
NOTICE: See NOTICE on Page 3D-1 of this 3-COIL SPRING
1. Position track bar brace and loosely install nut Fig. 603 Coil Springs and Insulator and bolt at body bracket.
2. Position other end of track bar brace at body
bracket. Install three screws and torque screws.
3. Torque track bar nut at body brace.

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.)