brake fluid PONTIAC FIERO 1988 Service Repair Manual

MAINTENANCE AND LUBRICATION OB-1
SECTION OB
NTENANCE AND LUBR
CONTENTS
Maintenance Schedule, Gasoline .............................................. OB-l
Maintenance Schedules I and 11 .............................................. OB-2
Owner Inspections
......................................................... OB-3
Recommended Fluids and Lubricants ......................................... OB-6
PASSENGER CAR MAINTENANCE SCHEDULE
VEHICLES
WITH GASOLINE ENGINE
NORMAL CAR USE ITEM 4
The maintenance services contained in Schedules I Carburetor or Throttle Body Mounting Bolt
and 11 are based on the assumption that your car will be Torque* used as designed:
Check torque of mounting bolts and/or nuts. @ To carry passengers and cargo within the limits
shown on the Tire Placard located on the edge of the ITEM 5 driver's door.
@ On reasonable road surfaces within legal driving Engine Idle Speed Adjustment*
limits. (Engines
without Idle Speed Control or Idle Air
Control) - Adjust to specifications shown on the under- @ On unleaded gasoline.
hood label. If no specifications are shown on the label, no
adjustment is necessary. Calibrated test equipment must
EXPLANATION OF SCHEDULED MAINTENANCE be used. SERVICES
The services listed in Maintenance Scheduies I and ITEM 6
11 are further explained below. When the following main- ~i~~ and wheel aotation tenance services are performed, make sure all parts are
replaced and all necessary repairs are done before driving To equalize wear and obtain maximum tire life,
your car. Be sure to use the proper fluid and lubricants as rotate in accordance with patterns shown in Owner's
shown in Figure OB-2. Manual.
ITEM 1
Engine Oil and Oil Filter Change*
ALWAYS USE SFICC OR SF/CD ENERGY CON-
SERVING OILS OF PROPER VISCOSITY
- Also.
always change oil and filter as soon as possible after
driving in a dust storm. See your Owner's Manual for
further details.
ITEM 2
Chassis Lubrication
Lubricate all grease fittings in suspension and steer-
ing linkage. Lubricate
transmissionltransaxle shift
linkage, parking brake cable guides, underbody contact
points and linkage. Also lubricate clutch cross shaft lever
every
30,000 miles (50 000 km) on rear-wheel-drive cars
only.
ITEM 3
Carburetor Choke and Hoses*
If your car is equipped with a carburetor, verify that
choke and vacuum break work properly and are within
specifications. Correct any binding caused by damage or
gum on the choke shaft. Inspect hoses for proper hookup,
cracks, chafing or decay. Correct as necessary.
Vacuum or A.I.R. Pump Drive Belt Inspection*
When a separate belt is used to drive the vacuum or
A.I.R.
pump, inspect it for cracks, fraying, wear and
proper tension. Adjust or replace as needed.
ITEM 8
Cooling System Service*
Drain, flush and refill system with new coolant. See
your Owner's Manual
for further details.
ITEM 9
Wheel Bearing Repack (Rear-Wheel-Drive Cars
Only Except Corvette)
Clean and repack front wheel bearings at each brake
relining or 15,000 miles
(25 000 km), whichever comes
first, when car is used in such service as police, taxi or
door-to-door delivery. If you do not use your car in such
service, clean and repack bearings at each brake relining
or 30,000 miles
(50 000 km), whichever comes first.
Corvette models do not require wheel bearing repack.

F CARLINE
ITEM 10
TransmissionRransaxle Service
The manual transmission or transaxle fluid does not
require changing. (Corvette only.) Change fluid in over-
drive unit every 30,000 miles (50 000 km).
For automatic transmissions or transaxles, change
both the fluid and filter every 15,000 miles (25 000 km) if
the car is mainly driven under one or more of these
conditions:
@ In heavy city traffic where the outside temperature
regularly reaches 90°F (32°C) or higher.
@ In hilly or mountainous terrain.
@ Frequent trailer pulling.
@ Uses such as found in taxi, police car or delivery
service.
If you do not use your car under any of these condi-
tions, change both the fluid and filter every 100,000 miles
(160 000 km). See you Owner's Manual for further
details.
ITEM 11
Spark Plug Service*
Replace spark plugs with type listed in your Owner's
Manual.
ITEM 12
Spark Plug Wire Inspection*
Clean wires and inspect for burns, cracks or other dam-
age. Check the wire boot fit at distributor and at spark plugs.
Replace wires as needed.
ITEM 13
Positive Crankcase Ventilation (PCV) Valve
Inspection*
Inspect valve for proper function. Replace valve if
necessary as well as any worn, plugged or collapsed
hoses.
ITEM 14
EGR System Service*
Conduct EGR System Service as referenced in the
EGR System Chart shown in the appropriate 6E Section.
Also, refer to your GM maintenance schedule booklet for
specific applications.
ITEM 15
Air Cleaner and PCV Filter Replacement*
On 1.6 and 2.0 liter engines, replace every 50,000
miles (80 000 km). On all other engines, replace every
30,000 miles (50 000 km). Replace more often under
dusty conditions. Ask your dealer for the proper replace-
ment interval for your driving conditions.
MAINTENANCE AND LUBRICATION 08-3
ITEM 16
Engine Timing Check*
Adjust timing to underhood label specifications. If
no specifications are shown, no adjustment is needed.
ITEM 17
Fuel Tank, Cap and Lines Inspection*
Inspect fuel tank, cap and lines (including fuel rails
and injection assembly, if so equipped) for damage or
leaks. Inspect fuel cap gasket for an even filler neck
imprint or any damage. Replace parts as needed.
ITEM 18
Thermostatically Controlled Air Cleaner
Inspection*
If your car is equipped, inspect all hoses and ducts
for proper hookup. Make sure valve works properly.
OWNER INSPECTIONS AND SERVICES
Listed below are inspections and services which
should be made by either you or a qualified technician at
the intervals shown to help ensure proper safety, emission
performance and dependability of your car. Take any
problems promptly to your dealer or another qualified
technician for service advice. Whenever repairs are neces-
sary, have them completed at once. For your safety and
that of others, any safety-related parts that could have
been damaged in an accident should be inspected and all
needed repairs should be done before operating your car.
Be sure to use the proper fluids and lubricants as shown in
Figure OB-2.
WHILE OPERATING YOUR VEHICLE
Automatic transmissionltransaxle shift indi-
cator operation - Make sure the indicator points to the
gear chosen.
Horn operation - Blow the horn occasionally to
make sure it works. Check all button locations.
I
Brake system operation -- Be alert to abnormal
sounds, increased brake pedal travel or repeated pulling to
one side when braking. Also, if a brake warning light
comes on or flashes, or the anti-lock warning light (if
equipped) comes on or remains on, something may be
wrong with part of the brake system. Have it inspected and
repaired at once.
Exhaust system operation - Be alert to any
changes in the sound of the system or any smell of fumes.
These are signs the system may be leaking or overheating.
.
Have it inspected and repaired at once. Also see "Engine
Exhaust Gas Caution (Carbon Monoxide)" and "Catalytic
Converter" in your Owner's Manual.
*An Emission Control Service

OB-4 MAINTENANCE AND LUBRICATION
Tire and wheel operation - Be alert to a vibra-
tion of the steering wheel or seat at normal highway
speeds. This may mean a wheel balance is needed. Also, a
pull right or left on a straight, level road may show the
need for
a tire pressure adjustment or wheel alignment.
Steering system operation - Be alert to
changes in steering action. An inspection is needed when
the steering wheel is harder to turn or has too much free
play or if unusual sounds are noted when turning or
parking.
Headlight aim operation - Take note of light
pattern occasionally. If beam aim doesn't look right,
headlights should be adjusted.
AT EACH FUEL FILL
Engine oil level check - Check engine oil level
and add if necessary. See your Owner's
Manual for further
details.
NOTICE: A large loss in this system may indicate a
problem. Have it inspected and repaired at once.
Engine coolant level and condition - Check
engine coolant level in coolant reservoir tank and add if
necessary. Replace if dirty or rusty. See your Owner's
Manual for further details.
NOTICE: A large loss in this system may indicate a
problem. Have it inspected and repaired at once.
Windshield washer fluid level check -- Check
washer fluid level in container and add if necessary.
Hood latch operation - When opening hood on
cars equipped with hoods that open from the front, note
the operation of secondary latch. It should keep hood from
opening all the way when primary latch is released. Make
sure that hood closes firmly.
AT LEAST MONTI-ILY
Tire and wheel inspection and pressure
check--
Check tires for abnormal wear or damage. Also,
check for damaged wheels. Keep pressures as shown on
Tire Placard on the driver's door (include spare unless it is
a stowaway). Pressure should b\: checked when tires are
"cold". See "Tires" in Owner's Manual for further
infomation.
Light operation check - Check operation of
license plate light, side-marker lights, headlights includ-
ing high beams, parking lights, taillights, brake lights.
turn signals, backup lights, instrument panel and interior
lights and hazard warning flashers.
Fluid leak check - After the car has been parked
for a while, inspect the surface beneath the car for water,
oil, fuel or other fluids. Water dripping from the air
conditioning system after use is normal. If you notice fuel
leaks or fumes, the cause should be found and corrected at
once.
AT LEAST TWICE A YEAR (FOR EXAMPLE,
EVERY SPRING AND FALL)
Power steering pump fluid level check --
Check power steering pump fluid level in accordance with
Owner's Manual instructions and keep at proper level.
NOTICE: A large loss in this system may indicate a
problem. Have it inspected and repaired at once.
Brake master cylinder reservoir fluid level
check ---- Check fluid and keep at proper level. Note: It is
normal for the brake fluid level to go down slightly as the
brake pads wear
- so be sure to keep reservoir filled.
NOTICE: A large loss in this system may indicate a
problem. Have
it inspected and repaired at once.
Clutch system service --- manual transmis-
sionltransaxle --- For cars equipped with hydraulic
clutch system, check the reservoir fluid level and add fluid
as required. All others, check clutch pedal free travel and
adjust as necessary. See your Owner's Manual for further
details.
~
NOTICE: A large loss in this system may indicate a
problem. Have it inspected and repaired at once.
Weatherstrip Lubrication - Clean surface and
then apply a thin film of silicone grease with a clean cloth.
EACH TIME OIL IS CHANGED
Automatic and manual transmissionltrans-
axle fluid level check - Check transmission/transaxle
fluid level and add as required. (Corvette only) if equipped
with manual transmission
- check fluid in the overdrive
unit and add as required.
NOTICE: A large loss in this system may indicate a
problem. Have
it inspected and repaired at once.
Brake systems inspection - For convenience,
the following should be done when wheels are removed
for rotation: Inspect lines and hoses for proper hookup,
binding, leaks, cracks, chafing, etc. Inspect disc brake
pads for wear and rotors for surface condition. Also in-
spect drum brake linings for wear and cracks. Inspect
other brake parts, including drums, wheel cylinders, park-
ing brake, etc. at the same time. Check parking brake
adjustment.
INSPECT BRAKES MORE OFTEN IF DRIVING
HABITS OR CONDITIONS RESULT IN FREQUENT
BRAKING.
Steering, suspension and front drive axle
boot and seal inspection
- Inspect front and rear
suspension and steering system for damaged, loose or
missing parts, signs of wear or lack of lubrication. Inspect
power steering lines and hoses for proper hookup, bind-
ing, leaks, cracks, chafing, etc. (On cars equipped with
manual steering gear, check for seal leakage.) On
front-
wheel-drive cars, clean then inspect drive axle boot seals
for damage, tears or leakage. Replace seals if necessary.
Exhaust system inspection - Inspect complete
system. Inspect body near the exhaust system. Look for
broken, damaged, missing or out-of-position parts as well
as open seams, holes, loose connections or other condi-
tions which could cause a heat buildup in the tloor pan or
could let exhaust fumes seep into the trunk or passenger
compartment.

MAINTENANCE AND LUBRICATION OB-5
Throttle linkage inspection -- Inspect for inter-
ference, binding, damaged or missing parts.
Engine drive belts inspection - Inspect all
belts for cracks, fraying and wear. Adjust or replace as
needed.
Rear axle service (if equipped) - Check gear
lubricant level and add if needed. For cars equipped with a
limited slip rear axle, fluid does not require changing
(except Caprice and Corvette
- change fluid and required
additive at first
7,500 miles (12 500 km). See your
Owner's Manual or "Recommended Fluids
& Lubricants
Chart" in this section.
IF YOU USE YOUR GAR TO PULL A TRAILER,
CHANGE GEAR LUBRICANT EVERY 7,500 MILES
(12 500 KM).
NOTICE: A large loss in this system may indicate a
problem. Have it inspected and repaired at once.
Power antenna - Clean and then lubricate power
antenna mast. The proper lubricant as shown in Figure
OB-2 should be used.
AT LEAST ONCE A YEAR
Lap and shoulder belts condition and opera-
tion
- Inspect belt system, including webbing, buckles,
latch plates, retractors, guide loops and anchors.
Moveable head restraint operation - On cars
with moveable restraints, make sure restraints stay in the
desired position. (See adjustment instructions in your
Owner's Manual.)
Seatback latch and recliner operation on
cars equipped
with recliner seat --- Be sure seat-
backs latch on those cars with folding seats using mechan-
ical latches. Make sure the recliner is holding by pushing
and pulling on the top of the
seatback while it is reclined.
See your Owner's Manual for seat operating information.
Spare tire and jack storage- Be alert to rattles
in rear of car. Make sure the space tire, all jacking equip-
ment, any tire inflator and any covers or doors are securely
stowed at all times. Oil jack ratchet or screw mechanism
after each use.
Key lock service - Lubricate key lock cylinder at
least annually.
Body lubrication service - Lubricate all body
door hinges including the tailgate or hatchback lid (if
equipped). Also lubricate the body hood, fuel door and
rear compartment hinges and latches including interior
glove box and counsel doors, and any folding seat
hardware.
"Fansmissionltransaxle neutral or clutch
starl switch operation
CAUnON: Before pedorming the follow-
ing safety switch check, be sure to have
enough room around the car. Then, firmly
apply both the parking brake (see your
Owner's Manual for procedure) and the
regular brakes. Do not use the accelerator pedal.
If the engine
starls, be ready to turn
off the ignition promptly. Take these pre-
cautions because the car could move
without warning and possibly cause per-
sonal injury or properly damage. On auto-
matic transmissionltransaxle cars, try to
starl the engine in each gear. The starler
should crank only in "Park" or "Neutral."
On manual transmissionltransaxle cars,
place the
shiR lever in "Neutral," push the
clutch halfway and try to starl. The starler
should crank only when the clutch is fully
depressed.
Steering column lock operation
- While
parked, try to turn key to "Lock" in each gear range. The
key should turn to "Lock" only when gear is in "Park" on
automatic or "Reverse" on manual
transmissionltransax-
le. On cars with key release lever, try to turn key toULock"
without depressing the lever. The key should turn to
"Lock" only with the key lever depressed. On all vehicles,
the key should come out only in "Lock."
Parking brake and transmissionltransaxle
"Park" mechanism operation
CAUT1ON:Before checking the holding
ability of the parking brake and automatic
transmissionltransaxle "Park" mecha-
nism, park on a fairly steep hill with
enough room for movement in the down-
hill direction. To reduce the risk of person-
al injury or property damage, be prepared
to apply the regular brakes promptly if the
car begins to move.
To check the parking brake, with the engine running and
transmission/transaxle in "Neutral." slowly remove foot
pressure from the regular brake pedal (until the car is held
by only the parking brake).
To check the automatic transmissionltransaxle "Park"
mechanism holding ability, release all brakes after shift-
ing the transmissionltransaxle to "Park."
ljnderbody flushing - At least every spring,
tlush from the underbody with plain water any corrosive
materials used for ice and snow removal and dust control.
Take care to thoroughly clean any areas where mud and
other debris can collect.
Sediment packed in closed areas
of the vehicle should be loosened before being flushed.
Engine cooling system service - Inspect
coolant and freeze protection. If dirty or rusty, drain, flush
and refill with new coolant. Keep coolant
at the proper
mixture as specified in your Owner's Manual. This pro-
vides proper freeze protection. corrosion inhibitor level
and engine operating temperature. Inspect hoses and re-
place if cracked. swollen or deteriorated. Tighten hose
clamps. Clean outside of radiator and air conditioning
condensor. Wash radiator filler cap and neck.
To help
ensure proper operation. a pressure test of both the cooling
system and cap is also recommended. (See maintenance
schedule charts in Figure
OB-l for the recommended
coolant change interval.)

NOTE: Fluids and lubricants identified below by name, part number or specification may be obtained from your GM dealer.
Figure 00-2 Recommended Fluids and Lubricants
USAGE
Engine
Oil
Engine Coolant
Brake and
Hydraul~c Clutch Systems
Parking Brake Cables
Power Steering System
Manual
Steerlng Gear (reclrculat~ng ball)
Automatic
Transrn~ssionRransaxle and 5 Speed Manual Transm~ss~ons
Manual Transm~ssion (rear-wheel-drive) 4 Speed
Manual
Transm~ss~onRransaxle Shin Linkage
Key Lock Cylinders
Automatic Transmlss~onfrransaxle Shlft Llnkage
Clutch Llnkage Plvot Po~nts
Floor Sh~n L~nkage
Power Antenna Mast (3-mast sect~on-type only)
Chass~s Lubr~cation
Standard D~fferent~al Rear Axle
L~m~ted-Sl~p D~flerent~al Rear Axle
W~ndsh~eld.Washer Solvent
Hood Latch Assembly
a)
Plvots and Sprlng Anchor
b) Release Pawl
Front Wheel Bearings
(rearqwheel-drive)
Hood and door hlnges, statlon wagon tailgate hlnge or hatchback Ild and Ilnkage, headl~ght door assembl~es, statlon wagon rear foldrng seat, fuel door hlnge, rear compartment Ihd hlnges
Weatherstr~ps
FLUlDlLUBRlCANT
GM Goodwrench Motor 011 or equivalent for API Se~lce, SFICC or SFICD of the
recommended v~scos~ty
M~xture of water and good qual~ty ethylene glycol base antllreeze conforming to GM spec 1825M (GM Part No 1052753)
Delco Supreme 11
Fluld (GM Part No 1052535) or DOT-3 Fluld
Chass~s grease meetlng requirements of GM-6031M (GM Part No 1052497)
GM power
steerlng flu~d, Part No 1052884 or equivalent
Use lubricant meetlng requirements of GM-4673M (GM Part No 1052182)
DEXR0N'-II Automat~c Transm~ss~on Flu~d (GM Part No 1051855) Camaro and Flreblrd (5 Speed)
Corvette overdr~ve unlt - DEXRON a.II All others SAE-80W-90 GL-5 gear lubr~cant (GM Part No 1052271)
Chass~s grease meetlng requirements of GM-6031M (GM Part No 1052497)
Black Key Lock
Cyl~nders - light oil (GM Par1 No. 1052949)
All other Key Lock Cyl~nders - sllicone lubrlcant (GM Part No 1052277)
Eng~ne 011
Eng~ne 011
Eng~ne 011
Llght 011 (GM Part No 1052949)
Chass~s grease meetlng requirements of GM-6031M (GM Part No 1052497)
SAE
80W or SAE 80W-90 GL-5 (SAE 80W GL-5 In Canada) gear lubricant (GM Part No
1052271)
For Camaro only
- Use SAE BOW190 GL-5+ Hypold 011 (GM Part No 1050010), 11 equ~pped wl5 7L (L98) Englne or 5 OL (LB9) engine wmpeed manual transm~ss~on and disc brakes
All other applications - Use SAE 80W or SAE 80W-90 GL-5 Gear Lubr~cant (GM Part No
1052271)
GM
Opt~kleen Washer Solvent (GM Part No 1051515) or equ~valent
a) Eng~ne 011 b) Chass~s grease meet~ng requirements of GM.6031M (GM Part No 1052497)
Lubricant GM Part No 1051344 grease or equivalent
Eng~ne 011
S~l~cone Grease (GM Part No 1052863) or equivalent

STEERING, SUSPENSION, f IRES AND WHEELS DIAGNOSIS 3.1
SECVION 3
STEER NG, SUSPENS
WHEELS
AGNOS
CONTENTS
........................................... General Information 3- 1 ............................................ General Diagnosis 3- 1
Power Recirculating Ball .................................. 3-3
................. Steering Linkage ........................ .. 3-3
Power Steering Pump ................... ... ............ 3-4
Steering Column
Lock System
........................... ... ................ 3-4
Column ............................................................ 3-5
........................................ Turn Signal Switch 3-6
Ignition Switch .............................................. 3-7
Key Reminder .............................................. 3-7
Dimmer Switch .................... ... ................ 3-10
Pivot and Switch Assembly ............................ 3-10
Steering Gear and Pump Leaks .......................... 3- 10
Seal Replacement Recommendations ................. 3- 10
Power Steering System Test Procedure .............. 3-12
................ Strut Dampener and Shock Absorber 3- 12
Tires ........................ .. ..................................... 3- 13
Vibrations .......................... .............. .................... 3- 14
.......................... Tapered Roller Bearings .. .... 3- 14
Trim Height .............................................. 3-14
GENERAL INFORMATION Abnormal or Excessive Tire Wear
Since the problems in steering, suspension, tires
and wheels involve several systems, they must all be
considered when diagnosing a complaint. To avoid
e Front-wheel or rear-wheel alignment
using the wrong symptom, always road test the car
o Sagging or broken springs
first. Proceed with the following preliminary checks
Tire out of balance and correct any substandard conditions which are worn strut dampener or shock absorber found. o Hard driving
--
e Tires for wrong pressure and uneven wear
o Joints from the column to the steering gear for
loose connectors or wear
o Front and rear suspension, and the steering gear
or linkage for loose or damaged parts
Out-of-round or out-of-balance tires, bent wheels,
and loose and/or rough wheel bearings
@ Power steering system for leaks. Also check the
power steering fluid level and the pump drive belt
tension
GENERAL DIAGNOSIS
Car Pulls (Leads)
Inspect
Mismatched or uneven tires
Broken or sagging springs
Radial tire lateral force
Front-wheel or rear-wheel alignment
o Steering gear valve off center (unbalanced)
e Front brakes dragging
a Overloaded car
e Not rotating tires
Scuffed Tires
o Toe incorrect
e Excessive speed on turns
o Suspension arm bent or twisted
Wheel Tramp
Inspect
o Blister or bump on tire
o Improper strut dampener or shock absorber
action
Shimmy, Shake or Vibration
inspect
e Tire or wheel out of balance
e Worn wheel bearings
a Worn tie rod ends
o Worn lower ball joints

FRONT SUSPENSION 3C-5
CALIPER
Remowd
NOTICE: See "Notice" on Page 3C-1 of this section.
1. Remove two thirds of the total fluid capecity from the meter cylinder reservoir that supplies fluid to the rystemrls) baing ~~iCed. Removal of the fluid is ne-
cessary to prevent nservoir overflow when the caliper
piston is pushed back in its bore to remove the caliper. Dircard the.brake fluid removed.
2. Raise the vehicle on a hoist and rumove (he wheel
covers and wheel assemblies, Position a 7" "C" clamp
on the caliper ro that solid side of the clamp resu against the metal part of the outboard shoe. Tighten the "C" clamp until the caliper mwes away from the vehicle far enough to push the piston to the bottom of
the piston bore. This will allow the shoes to back off
from the
rotcr surfaces. Remove the "C" clamp.
Mipr Installation
1. Position the caliper over the rotor, lining up the holes in
the caliper can with the holes in (he mounting brmket.
NOTICE: When rsinrtalling calipsr bc sure you hwe not
turned it over, end over end. This would cause s even twist in the brake hose. After poritioning caliper on dirc, observe brake hose being sun it is not twisted.
2. Start (he bolts through the rlmves in the inboard caliper ears and through the mounting brmket, making sure
that the ends of the bolts pars under (he rstaining esn on the inboard ohm. Push bolts on through to
engage the holes in the outboard rhm and the outboard
caliper ears at the same time, thmrding the bolts into
the mounting brwket. Torque the bolts to 47 N-m (35 Ib. tt.).
NOTICE: See "Notice" on Psge 1 of this section.
3. It
is not necessary to disconnect the brake lines. Re-
3. Add fresh approved brake fluid to the master cylinder
rnwe the two mounting bolts which attach the caliper
reservoirs to bring the level up to within 3mm [I/&') ot
to the support bracket. Lift caliper off the rotor. Sup.
the top.
port caliper.
4. Pump brake pedal to seat linings
wainst rotor.
5. Recheck the brake system.
I I
FI~ 605 Ren~ov~ng and Iristalltrig Callper

481-4 REAR AXLE
Gear Noise
Gear noise (whine) is audible from 20 to 55 mph
under four driving conditions:
1. Light Acceleration - Accelerate slowly.
2. Road Load
- Car
driving load or constant speed.
3. Float - Using enough throttle to keep the car from
driving the engine
- car slows down gradually but
engine still pulls slightly.
4. Coast - Throttle closed and car in gear.
Bearing Noise
Bad bearings generally produce more of a rough
growl or grating sound, rather than the whine typical
of gear noise. Bearing noise frequently "wow-wows" at
bearing rpm, indicating a defective pinion or rear axle
case side bearing. This noise could easily be confused
with rear wheel bearing noise. Inspect and replace as
required.
Rear Wheel Bearing Noise
A rough rear wheel bearing produces a noise
which continues with car coasting at low speed and
transmission in neutral. Noise may diminish some by
gentle braking. With rear wheels jacked up, spin rear
wheels by hand while listening at hubs for evidence of
rough (noisy) wheel bearing.
Knock At Low Speeds
Low speed knock can be caused by worn
universal joints or a side gear hub counterbore in a case
that has worn oversize. Inspect and replace universal
joint or case and side gear as required.
Backlash Clunk
Excessive clunk with acceleration and deceleration
is caused by worn differential pinion gear shaft, excessive
clearance between axle shaft and side gear splines, exces-
sive clearance between side gear hub and counterbore in
case, worn pinion and side gear teeth, worn thrust washers
and excessive drive pinion and ring gear backlash. Re-
move worn parts and replace as required, selecting close
fitting parts when possible. Adjust pinion and ring gear
backlash.
DIAGNOSIS
1. Noise
is the same in "Light Acceleration" or
"Coast".
a. Road noise.
b. Tire noise.
c. Front wheel bearing noise.
d. Rear axle bearing noise.
2. Noise changes on a different type of road.
a. Road noise.
b. Tire noise.
3. Noise tone lowers as car speed is lowered.
a. Tire noise.
b. Front
wheel bearings and rear axle bearings.
c. Gear noise.
4. Similar noise is produced with car standing and
driving. a.
Engine noise.
b. Transmission noise.
c. Exhaust noise.
5. Vibration.
a. Rough rear axle bearing.
b. Unbalanced or damaged propeller shaft.
c. Tire unbalance.
d. Worn universal joint in propeller shaft.
e. Mis-indexed propeller shaft at pinion
flange.
f. Pinion flange runout too great.
6. A knock or click approximately every two
revolutions of the rear wheel.
a. A rear axle bearing.
b. Worn case.
7. Noise most pronounced on turns.
a. Rear axle side gear and pinion noise,
differential gear noise.
b. Axle bearings.
8. A continuous low pitch whirring or scraping
noise starting at relatively low speed.
a. All bearing noise.
9. Drive noise, coast noise or float noise.
a. Ring
and pinion gear noise.
b. Front
pinion bearing noise, coast or drive.
c. Axle bearing noise.
10. Clunk
on
acceleration or deceleration.
a. Worn
rear axle pinion shaft splines.
b. Side
gear hub counterbore in case worn
oversize.
c. Worn U-joints.
d. Excessive transmission backlash.
e. Worn axle shaft splines.
11. Chatter on turns.
a. Wrong
lube in rear axle.
b. Clutch
cone worn or spalled.
12. Clunk
or knock on rough road operation.
a. Worn suspension bushings.
PRE-REPAIR INVESTIGATION AND TROUBLE
DIAGNOSIS
A carefull diagnosis of the rear axle prior to
disassembly will often reveal valuable information as to
the extent and type of repairs or adjustments necessary.
Since frequent causes of axle noises are improper
backlash, pinion bearing pre-load, or side bearing
pre-load, or a combination, a few simple adjustments
may be all that are necessary to correct a problem.
Before disassembling the rear axle, the following
checks should be made with the results recorded and
analyzed: 1) Backlash;
2) Total Assembly Preload; 3)
Tooth Contact Pattern Test; 4) Fluid Level; and 5)
Fluid Contamination.
If axle shaft end play is excessive then check
bearings, retainer, and bolts securing backing plate.
The axle bearings could be worn and need replacement.
The four bolts or nuts securing the brake backing plate
may be loose, stripped, or missing. If the inner bearing
retainer worked loose it must be replaced.
Use care at all times to keep dirt and other foreign
matter, such as grinder dust, soot or sand, away from
differential to prevent possibility of subsequent failure.

REAR AXLE 481-7
ON-VEHICLE SERVICE
CARRIER COVER AND GASKET
Remove or Disconnect
1. Having
a container in place remove drain plug
with tool
J-35117,remove cover bolts and pry
cover loose to drain lubricant.
2. Make sure both
gasket sealing surfaces are clean.
Install or Connect
Use cover gasket (do not assemble with
sealant alone).
NOTICE: Apply locktite part No. 573, GM Part
Nos. 1052080, or 1052279 or equivalent to cover
bolts before installing cover. If sealant is not applied
bolts may loosen causing fluid leak and damage to
rear axle assembly.
1. Torque cover bolts in a crosswise pattern to
insure uniform draw on gasket. Torque
26 N.m
(20 1b.ft.).
2. Fill with lubricant to bottom of filler plug hole.
Refer to specifications for correct lubricant usage
and quantity.
AXLE SHAFT
Remove or Disconnect
1. Wheel
and brake components as necessary.
2. The
four nuts holding the brake anchor plate and
outer bearing retainer.
3. Withdraw the axle shaft and wheel bearing assem-
bly using axle shaft remover
J 21579 and slide
hammer
J 2619-01 (Fig. 4).
Fig. 4 Axle Shaft Removal
4. Inner
bearing retainer and bearing from axle
shaft. To do this carefully split the retainer with
a chisel and remove from shaft. Press off bearing
with tool
5-22912-01 from axle. Discard bearing
and seal (Fig. 5).
Fig. 5 Bearing and Seal Removal
Examine axle shaft. If axle shaft is in satisfactory
condition it may be re-used.
Important
Bearings and inner bearing retainers which
have been removed from an axle shaft
should not be re-used.
Install or Connect
1. Place the outer bearing retainer on the axle shaft.
Important
Right and left hand axle shaft seals are
different in construction. Right hand seal is
black banded with right hand ridges. Left
hand seal is gold banded with left hand
ridges. The part numbers designate left and
right sides.
2. Place the oil seal on the axle shaft ensuring that
the spring side of the oil seal faces the center of
the axle. Lubricate seals lips with a light coat of
grease. Note use of excessive amounts of grease
may damage seal.
3. Press wheel bearing and inner bearing retainer hard
against bearing shoulder on axle shaft with tool
J 8853-01, ensuring that the retainer is tight against
the bearing and with
O.D. chamfer towards
bearing.
4. Place the axle shaft through the brake anchor
plate and align axle shaft and side gear splines.
5. Once the splines have been engaged in the side
gears the wheel bearing and oil seal may be
pushed into the housing.
A light coat of grease on
the seal outside diameter will assist in installation.
Tighten four backing plate bolts alternately. Use
new locknuts on bolts. (Refer to specifications).
NOTICE: If a limited-slip differential is used
ensure that both axle shaft splines are fully
engaged before the axle shafts are rotated. This is
to mainatain spline alignment, refer to limited-slip
instructions.

REAR AXLE 4Bl-I I
Fig. 11 Installing Wheel Bolt
Loosen parking brake cable adjuster nut and
remove two parking brake cables from adjuster
and body clips.
Shock absorbers from axle.
Track bar from rear axle and body.
Stabilizer bar links from axle and bushings.
Mark propeller shaft and companion flange, then
disconnect and remove propeller shaft.
Brake line junction block bolt at axle housing,
then disconnect brake lines at wheel cylinders.
Brake lines from clips.
Lower rear axle and remove springs.
Torque arm from rear axle.
Lower control arms from rear axle.
Lower hoist and remove rear axle assembly from
vehicle.
Install or Connect
Raise hoist and rear axle assembly.
Lower control arms to rear axle.
Torque arm to rear axle.
Springs and raise rear axle assembly.
Brake lines to clips.
Brake line junction block bolt at axle housing,
then connect brake lines at wheel cylinders or
calipers.
Align drive shaft and pinion flange, then install
drive shaft and connect.
Stabilizer bushings and links to axle.
Track bar to body and rear axle.
Shock absorbers to axle.
Parking brake cables to body clips and cable
adjuster, then tighten parking brake cable
adjuster nut.
Wheels and tighten lug nuts.
Frame supports and lower hoist.
NOTICE: Lubricant level is to the bottom of the
filler plug hole. Use only the specified lubricant.
(Refer to Specifications).
Before attempting any service procedures the
technician must know what type rear axle is to be
serviced. Refer to chart (Rear Axle Codes And
Identification) to identify codes, ring gear size, and ratios.
Remember that all ring gear bolts have
L.H.
threads.
Most rear axle service repairs can be made by
supporting the car by the frame with the axle housing
supported and lowered to its lowest travel. On some
models it may be necessary to disconnect shock
absorbers to obtain additional clearance. When doing
this, do not allow the rear brake hose to become
kinked
or stretched.
Lubricant may be drained by backing out all
cover bolts and breaking cover loose at the bottom.
If the rear axle housing is removed for any reason,
rear axle service can be performed on the bench.
When a new ring gear and pinion is installed, the
owner should be advised not to accelerate rapidly or
exceed 50 mph for the first 50 miles of driving.
It is necessary to perform a service diagnosis
before disassembly of the rear axle. Check all fasteners
with torque wrench for correct torque. Check level and
condition of fluid.
If fluid is contaminated the rear axle
will require disassembly and a complete inspection and
cleaning. The bearing preloads should be checked with
a torque wrench. A dial indicator reading should be
made for run out of ring gear and backlash between
ring and pinion gear. Use specifications from chart
below to perform suggested diagnostic checks. Roll
gears and paint to read out pattern.
DRAIN REAR AXLE ASSEMBLY
1. Loosen cover and pry cover away from carrier.
2. Let axle fluids drain from carrier.
3. Remove cover bolts and cover from carrier.
4. Scrape off gasket and sealer from cover and
carrier.
Remove or Disconnect
Differential Assembly
1. Bearing caps and bolts. Identify bearing caps with
paint. The bearing caps are not interchangeable.
2. The differential assembly is worked out of the
carrier by putting a box wrench on ring gear bolt.
The box wrench contacts back of housing when
companion
tlange is rotated with tool 3-8614-01.
When the differential assembly rotates out of the
carrier from pinion rotation the shims will also
come out. The shims and bearing caps location,
left or right, must be identified for reassembly.
(Fig. 12).
3. Differential assembly from carrier.
Remove or Disconnect
Hypoid Pinion and Pinion Bearings
1. Pinion nut and companion flange from pinion
with companion flange tool 5-8614-01. (Fig. 8).
2. Drive pinion gear through rear of carrier with
soft face hammer.