run flat PONTIAC FIERO 1988 Service User Guide

4A-4 PROPELLER SHAFT
PROPELLER SHAFT BALANCING
Hose Clamp Method
Figures 4A- 1 1 thru 4A-13
1. Place the vehicle on a twin post hoist so that the
rear of the vehicle is supported on the rear axle
housing and the rear wheels are free to rotate.
Remove both rear wheel assemblies and reinstall
wheel lug nuts with flat sides next to
drums/discs.
2. Mark and number propeller shaft at four (4)
points 90 degrees apart at rear of shaft just
forward of balance weight, as shown.
3. Install two (2) hose clamps on the rear of the
propeller shaft and slide them rearward until the
clamps stop at the nearest balance weight welded
to the tube. Align both clamps at any one of the
four marks made on shaft in Step 2 and tighten.
Be sure sufficient clearance is maintained so that
clamp heads do not contact floor pan of vehicle
when axle is in contact with rebound bumper in
frame. In order to gain sufficient clearance, it
may be necessary to position the clamps over the
balance weights.
4. Run the vehicle through the speed range to 80-90
MPH (130-145
Km/h) and note amount of
imbalance.
CAUTION: All persons should stay
clear of universal joint and balance
weight areas to avoid possible injury.
Do not run on hoist for extended
periods due to the danger of
overheating the transmission or
engine.
5. Loosen clamps and rotate clamp heads 90 degrees
to the next mark on a propeller shaft. Tighten
clamps and repeat Step 4.
6. Repeat Step 5 until car has been run with clamp
heads located at all four marks on shaft.
7. Position clamps at point of least imbalance.
Rotate the clamp heads away from each other 45
degrees (one on each side of the position), as
shown. Run the vehicle and note if imbalance has
improved.
In some cases it may be necessary to use one
clamp or possibly three clamps in order to obtain
a good balance. Replace shaft if three hose clamps
do not improve the imbalance.
8. Continue to rotate the clamps apart in smaller
angular increments until the imbalance is at its
minimum.
9. Reinstall wheel assemblies and road test the
vehicle for final check of balance. A minimal
vibration felt in the vehicle on the hoist may not
show up during a road test.
Strobe Light Method
Figures 461- 1 1, $A- 14, and 4A- 15
If a wheel balancer of the strobe light type is
available, the use of such a unit will facilitate the
balancing of the propeller shaft. The balance pick-up
unit should be placed directly under the nose of the
rear axle carrier and as far forward as possible. 1.
Place
the vehicle on a twin post hoist so the rear of
the vehicle is supported on the rear axle housing and
the rear wheels are free to rotate. Lower rear hoist
and allow axle to rest on jackstands. The groove in
the rear hoist fixture could clamp the axle and de-
stroy the sensitivity of the operation. Remove both
rear wheel assemblies and reinstall wheel lug nuts
with flat sides next to the
drums/rotors.
2.
Mark and number drive shaft at 4 points 90
degrees apart at rear of shaft just forward of
balance weights, as shown.
3. Place the strobe light wheel balancer pick-up
under the nose of the carrier.
4. Run vehicle in gear at the speed where the
distrubance is at its peak, allow the driveline to
stabilize by holding at a constant speed. Point
strobe light up at the spinning propeller shaft and
note position of one of the reference numbers.
Shut off engine and position the propeller shaft so
the reference numbers will be in the same position
as was noted while the shaft was rotating.
When strobe light flashed, the heaviest point of
the shaft was at the bottom (6 o'clock). To
balance the propeller shaft, it would be necessary
to apply the balancing weights (hose clamps) 180
degrees away from the heaviest point or at the top
of the propeller shaft (12 o'clock).
5. Install two screw-type hose clamps on the
propeller shaft as close to the rear as possible.
Position both clamp heads 180 degrees from the
heaviest point of drive shaft as indicated by strobe
light. Tighten clamps.
NOTICE: Be sure sufficient clearance is
maintained so clamp heads do not contact floor
pan of vehicle when axle is in contact with rebound
bumper on frame. In order to gain. sufficient
clearance, it may be necessary to position the
clamps over the balance weights.
6. Run vehicle through the speed range 80-90
M.P.
H. (130-145 Km/h). If disturbance is gone,
nothing further need be done on the hoist. If the
disturbance is not gone and the strobe light shows
the clamp heads at the bottom (6 o'clock) of the
shaft, go to Step
7. If the strobe light shows the
two clamp heads at the top of the shaft, add one
more hose clamp and recheck. If the strobe light
shows the three clamp heads at the top of the
shaft, remove the propeller shaft and
reindex it
180 degrees on the rear axle pinion companion
flange. Recheck with no clamps. Repeat balance
starting with Step 5. If the shaft still needs more
than three hose clamps at the same clock position,
replace it. If the clamps are also 180 degrees from
their original position after the propeller shaft
was reindexed 180 degrees, the rear axle pinion
companion flange is out of balance and must be
replaced. DO NOT use more than three hose
clamps to balance the shaft. If the strobe light
shows the hose clamps at the bottom of the shaft,
but the disturbance still exists, go to Step
7.

4A-10 PROPELLER SHAFT
STEP 1
DETERMINE POINT
OF UNBALANCE STEP
2 STEP 3
ADD
HOSE CLAMPS 180 FROM POINT OF UNBALANCE UNlTL THEY BECOME
HEAVY SPOT ROTATE
TWO CLAMPS EQUALLY
AWAY FROM EACH OTHER
UNTIL BEST BALANCE
IS ACHIEVED
1. SHEARED NYLON 2. INJECTION RING INJECTION RINGS REMOVED FROM
BEARING CAP
Figure 4A-16 Production U-Joints-Nylon Injected Ring
Type
1. BEARING CAP 5. SHIELD
2. SNAP RING 6. SEAL
3. FLAT DELRIN WASHER 7. NEEDLE BEARING
4. SPIDER 8. ROUND DELRIN WASHER J10017-4A-F
Figure 4A-17 U-Joints-External Snap Ring Type
1. CROSS PRESS
2.
1 118 (30rnrn) SOCKET TO
SUPPORT YOKE
EAR, BUT MUST
CLEAR BEARING
CAP
J~oo~~-~A-F
Figure 4A-18 Pressing Out Universal Joint Bearing Cap
2. J 9522-5
3. BEARING CAP
Figure 4A-19 Spacer Tool J-9522-5 Installation
5. Press against opposite bearing caps, working the
of the trunnions in the bearing caps. If there
cross all of the time to check for free movement
seems to be a hang-up, stop pressing and recheck

4819 REAR AXLE
bears against the inner race of the front bearing and a
shoulder on the pinion stem. This spacer is used to
enable accurate bearing pre-load adjustment and
maintain a pre-load on both front and rear pinion
bearings, Adjustment of the fore and aft position of the
pinion is obtained by placing a shim between the rear
pinion bearing cup and axle housing. The differential
case is of two-piece construction and is supported in
the carrier by two tapered roller side bearings. Pre-load
rear axle case by inserting shims between the bearings
and the carrier. The rear axle case assembly is
positioned for proper ring gear to pinion backlash by
varying the shim thickness from side to side. The ring
gear is bolted to the case. Two side gears have splined
bores for driving the axle shafts. They are positioned
to turn in counterbored cavities in the case. The four
rear axle pinions have smooth bores and are held in
position by a pinion cross shaft, mounted and locked
in the rear axle case. All six gears are in mesh with each
other and because the pinion gears turn freely on their
shaft, they act as idler gears when the rear wheels are
turning at different speeds. The pinions and side gears
are backed by steel thrust washers.
LIMITED-SLIP REAR AXLE
The operation of the Limited-Slip differential is
the same as the standard differential, except that there
is additional friction provided by the conical clutches.
Under ordinary driving and cornering conditions, the
cones slip, allowing the outside wheel to turn faster
than the inner. Under poor traction conditions, such as
ice, snow, or loose gravel under one driving wheel, the
increased friction provided by the cones increases the
driving torque available to the wheel with the better
traction. The cones are spring loaded to provide the
increased driving torque under extremely low traction
conditions.
Operation
When the vehicle turns a corner, the outer rear
wheel must turn faster than the inner wheel. The inner
wheel, turning slower than the outer wheel, slows its
differential side gear (as the axle shaft is splined to the
side gear) and the differential pinion gears will roll
around the slowed differential side gear, driving the
other differential side gear and wheel faster.
DIAGNOSIS AND TESTING
Many noises reported as coming from the rear
axle assembly actually originate from other sources
such as tires, road surfaces, front wheel bearings, axle
bearing, engine, transmission, muffler or body
drumming. A thorough and careful check should be
made to determine the source of the noise before
disassembling the rear axle. Noise which originates in
other places cannot be corrected by adjustment or
replacement of parts in the differential. It should also
be remembered that rear axle gears, like any other
mechanical device, are not absolutely quiet and should
be accepted as being commercially quiet unless some
abnormal noise is present.
To make a systematic check for axle noise under
standard conditions, observe the following:
1. Select a level smooth asphalt road to reduce tire
noise and body drumming.
2. Check rear axle lubricant to assure correct level,
then drive car far enough to thoroughly warm up
rear axle lubricant, approximately 10 miles.
3. Note speed and RPM at which noise occurs. Stop
car and put transmission in neutral. Run engine
slowly up and down through engine speeds,
corresponding to car speed at which noise was
most pronounced, to determine if it is caused by
exhaust, muffler roar or other engine conditions.
4. Tire noise changes with different road surfaces,
but rear axle noise does not. Temporarily
inflating all tires to approximately 50 pounds
pressure
for test purposes only will materially
alter noise caused by tires, but will not affect noise
caused by rear axle. Rear axle noise usually stops
when coasting at speeds under 30 miles per hour;
however, tire noise continues, but with lower
tone, as car speed is reduced. Rear axle noise
usually changes when comparing acceleration
and coast, but tire noise remains about the same.
Distinguish between tire noise and rear axle noise
by noting if noise varies with various speeds or
sudden acceleration and deceleration; exhaust
and axle noise show variations under these
conditions while tire noise remains constant and
is more pronounced at speeds of 20 to 30 miles
per hour. Further check for tire noise by driving
car over smooth pavements or dirt roads (not
gravel) with tires at normal pressure. If noise is
caused by tires, it will noticeably change or
disappear and reappear with changes in road
surface.
5. Loose or rough front wheel bearings will cause
noise which may be confused with rear axle
noises; however, front wheel bearing noise does
not change when comparing drive and coast.
Light application of brakes while holding car
speed steady will often cause wheel bearing noise
to diminish, as this takes some weight off the
bearing. Front wheel bearings may be easily
checked for noise by jacking up the wheels and
spinning them, also by shaking wheels to
determine if bearings are loose.
6. Rear suspension rubber bushings and spring
insulators dampen out rear axle noise when
correctly installed. Check to see that no metallic
contact exists between the spring and spring seat
opening in frame or between upper and lower
control arm bushings and frame or axle housing
brackets. The track bar and torque arm must be
bolted securely. Metal-to-metal contact at those
points may result in telegraphing road noise and
normal axle noise which would not be
objectionable if dampened by bushings.
AXLE NOISES
After the noise has been determined as being in
the axle by following the above appraisal procedure,
the type of axle noise should be determined to aid in
making repairs if necessary.

REAR AXLE 4B-3
Noise which originates in other places cannot be
corrected by adjustment or replacement of parts in the
differential. It should also be remembered that rear
axle gears, like any other mechanical device, are not
absolutely quiet and should be accepted as being
commercially quiet unless some abnormal noise is
present.
To make a systematic check for axle noise under
standard conditions, observe the following:
1. Select a level smooth asphalt road to reduce tire
noise and body drumming.
2. Check rear axle lubricant to assure correct level,
then drive car far enough to thoroughly warm up
rear axle lubricant.
3. Note speed and RPM at which noise occurs. Then
stop car and with automatic transmission in neutral,
run engine slowly up and down through engine speeds, corresponding to car speed at which noise
was most pronounced, to determine if it is caused by
exhaust, muffler roar or other engine conditions.
4. Tire noise changes with different road surfaces,
but rear axle noise does not. Temporarily
inflating all tires to approximately 50 pounds
pressure for
test purposes only will materially
alter noise caused by tires, but will not affect noise
caused by rear axle. Rear axle noise usually stops
when coasting at speeds under 30 miles per hour;
however, tire noise continues, but with lower
tone, as car speed is reduced. Rear axle noise
usually changes when comparing acceleration
and coast, but tire noise remains about the same.
Distinguish between tire noise and rear axle noise
by noting if noise varies with various speeds or
sudden acceleration and deceleration; exhaust
and axle noise show variations under these
conditions while tire noise remains constant and
is more pronounced at speeds of 20 to 30 miles
per hour. Further check for tire noise by driving
car over smooth pavements or dirt roads (not
gravel) with tires at normal pressure. If noise is
caused by tires, it will noticeably change or
disappear and reappear with changes in road
surface.
5. Loose or rough front wheel bearings will cause
noise which may be confused with rear axle
noises; however, front wheel bearing noise does
not change when comparing drive and coast.
Light application of brakes while holding car
speed steady will often cause wheel bearing noise
to diminish, as this takes some weight off the
bearing. Front wheel bearings may be easily
checked for noise by jacking up the wheels and
spinning them, also by shaking wheels to
determine if bearings are loose.
6. Rear suspension rubber bushings and spring
insulators dampen out rear axle noise when
correctly installed. Check to see that no metallic
contact exists between the spring and spring
opening in frame or between upper and lower
control arm bushings and frame or axle housing
brackets.
Metal-to-metal contact at those points
may result in telegraphing road noise and normal axle
noise which would not be objectionable if
dampened by bushings.
AXLE NOISES
Gear Noise
After the noise has been determined as being in
the
axle by following the above appraisal procedure,
the type of axle noise should be determined to aid in
maki~~g repairs if necessary.
Gear noise (whine) is audible from 20 to
55 mph
under four driving conditions:
1. Drive - Acceleration or heavy pull.
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. Gear
noise most frequently has periods where noise is
more prominent, usually 30 to 40 mph and 50 to
55 mph.
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.
I(noclc 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.
Baclclash Clunk
Excessive clunk with acceleration and
deceleration is caused by worn differential pinion shaft,
excessive clearance between axle shaft and side gear
splines, excessive clearance between side gear hub and
counterbore in case worn pinion and side gear teeth,
worn thrust washers and excessive drive pinion and
rear gear backlash. Remove worn parts and replace as
required, selecting close fitting parts when possible.
Adjust pinion and ring gear backlash.
REAR AXLE STANDARD AND LIMITED-SLIP
1. Noise is the same in "Drive" or "Coast".
a. Road noise.
b. Tire noise.
c. Front wheel bearing noise.

BRAKES 5-3
DIAGNOSIS AND INSPECTION
BRAKE SYSTEM TESTING
(Figures
2 through 4)
Brakes should be tested on dry, clean, reasonably
smooth and level roadway. A true test of brake performance
cannot be made if the roadway is wet, greasy or covered
with loose dirt so that all tires do not grip the road equally.
Testing will also be affected if the roadway is crowned
which would throw the weight of the car toward the wheels
on one side. If the roadway is too rough, the wheels will tend
to bounce. Test brakes at different car speeds with both light and
heavy pedal pressure, avoid locking the brakes and sliding
the tires. Locked brakes and sliding tires do not indicate
brake efficiency, because heavily braked, but turning
wheels will stop the car in less distance than locked brakes.
More tire-to-road friction is present with a heavily braked
turning tire than with a sliding tire. The brake system is designed and balanced to avoid
locking the wheels, except at very high deceleration levels.
The shortest stopping distance and best control is achieved
without brake lock-up.
Because of high deceleration capability, a firmer pedal
may be felt at higher deceleration levels.
External Conditions That Affect Brake Performance
1. Tires. Tires having unequal contact and grip on road
will cause unequal braking. Tires must be equally
inflated and tread pattern of right and left tires must
be approximately equal.
2. Car Loading. A heavily loaded car requires more
braking effort. When a car has unequal loading, the
most heavily loaded wheels require more braking
power than others.
3. Wheel Alignment. Misalignment of the wheels, par-
ticularly excessive camber and caster, will cause the
brakes to pull to one side.
4. Front Wheel Bearings. A loose front wheel bearing
BRAKE FLUID LEAKS
With engine running at idle and the transmission in neu-
tral, depress the brake pedal and hold a constant foot pres-
sure.
If the pedal gradually falls away with the constant
pressure, the hydraulic system may be leaking. Perform a
visual check to confirm any suspected leak.
Check the master cylinder fluid levels. While a slight drop
in reservoir level does result from normal lining wear, an
abnormally low level in either reservoir indicates
a leak in
the system. The hydraulic system may be leaking either
internally or externally. See "Master Cylinder Check."
Also, the system may appear to pass this test but still have
slight leakage.
If fluid levels are normal, check the vacuum booster
pushrod length. If an incorrect length pushrod is found,
adjust or replace the
pushrod. Check the service brake
pedal travel and the parking brake adjustment.
When checking the fluid levels, the master cylinder reser-
voir may be as low as
25 mm (1 inch) from the top if the front
linings are worn. This is not abnormal.
MASTER CYLINDER CHECK
These checks will help locate some master cylinder mal-
functions. Use the Brake Diagnosis Charts to help isolate
the problem if it is not found by using these tests.
1. Check for a cracked master cylinder casting or brake
fluid around the master cylinder. Leaks are indicated
only if there is at least a drop of fluid. A damp condi-
tion is not abnormal.
2. Check for a binding pedal linkage.
3. Disassemble the master cylinder and check for swol-
len or stretched piston
seal(s). If swollen seals are
found, substandard or contaminated brake fluid
should be suspected.
If contaminated, all compo-
nents should be disassembled and cleaned. All rub-
ber components should be replaced and all the pipes
should be flushed.
permits the front wheel to tilt and lose contact with the
SUBSTANDARD OR CONTAMINATED brake shoe linings causing erratic brake operation. BRAKE FLUID
WARNING LAMP OPERATION
The brake system uses a single red "BRAKE" warning
lamp located in the instrument panel cluster. When the
ignition switch is in the "START" position, the "BRAKE"
warning lamp should come on. It should go off when the
ignition switch returns to the "RUN" position.
The following conditions will activate the "BRAKE"
warning lamp:
1. Parking brake applied. The lamp should be on when
tfie parking brake is applied and the ignition switch is
"ON."
2. Pressure differential switch detects a failure. See
"Brake Pressure Differential Warning Switch" in this
section. Improper
brake fluid, mineral oil or water in the fluid may
cause the brake fluid to boil or the rubber components to
deteriorate.
If piston cups are swollen, the rubber parts have dete-
riorated. This deterioration may also be seen by swollen
wheel cylinder piston cups on the drum brake wheels or a
swollen master cylinder cover diaphragm.
If rubber deterioration is evident, disassemble all hydrau-
lic parts and wash with alcohol. Dry these parts with com-
pressed air before assembly to keep alcohol out of the
system. Replace all rubber parts in the system, including
hoses. Check for fluid on the linings. If excessive fluid is
found, replace the linings.
If master cylinder piston seals are satisfactory, check for
leakage or excessive heat conditions. If condition is not
found, drain fluid, flush with brake fluid, fill and bleed the
system.

BRAKES 5-15
lnspect rear drum brake shoe and lining assemblies.
Install or Connect (Figures 12 and 13)
When the thickness of any lining is worn within 0.76 mm
Raise vehicle. See Section OA. (0.030-inch)
of the shoe or rivet, the shoe and lining
1. Cable at brake shoe operating lever. assemblies must
be replaced. Replace shoe and lining
Bend retainer fingers. assemblies
in axle sets.
2. Brake drum and wheel.
3. Rear cable at connector.
0 Lower vehicle. See Section oA. INSPECTING AND REFINISHING ROTORS
Adjust
0 Parking brake. See Section 5C3.
Parking Brake Rear Cable (Disc Brakes)
Remove or Disconnect (Figures
12 and 13)
0 Raise vehicle. See Section OA.
1. Rear cable from connector.
0 Loosen adjusting nut at equalizer.
2. Cable from brake caliper.
Push forward on caliper parking brake apply
lever.
@ Remove cable from tang in lever.
Release lever.
Lower vehicle. See Section OA.
Install or Connect (Figures 12 and
13)
Raise vehicle. See Section OA.
1. Cable to brake caliper.
0 Push forward on caliper parking brake apply
lever.
0 Install cable in lever tang.
Release lever.
2. Rear cable to connector. 0 Lower vehicle. See Section OA.
0 Parking brake. See Section 586.
BRAKE LINING INSPECTION
(Figure 14)
lnspect the brake linings at least twice a year when the
wheels are removed (tire rotation, etc.). Check both ends of
the outer shoe by looking in at each end of the caliper.
These are the points at which the highest rate of wear nor-
mally occurs. Also, check the lining thickness of the inner
shoe to make sure that it has not worn prematurely. Look
through the hole in the top of the caliper to view the inner
shoe. When the thickness of any lining is worn to within
0.76
mm (0.030-inch) of the shoe or rivet, all disc brake
shoes and linings should be replaced in axle sets.
All disc brakes have a wear indicator that makes a noise
when the linings wear to a degree where replacement is
required. The wear indicator is an integral part of the shoe
and lining. When the lining is worn, the clip indicator con-
tacts the rotor and produces a warning noise.
Check flatness of brake linings. Place inner shoe lining
and outer shoe lining surfaces together and check for gap
between surfaces. If more than 0.13 mm
(.OO&inch) gap is
measured midway between attaching lugs, shoe and lining
assembly must be replaced. Thickness
Variation Check
Thickness variation can be checked by measuring the
thickness of the rotor at four or more points around the
circumference of the rotor. All measu'rements must be
made at the same distance in from the edge of the rotor. A
rotor that varies by more than
.013 mm (.0005-inch) can
cause pedal pulsation
and/or front end vibration during
brake applications. A rotor that does not meet these specifi-
cations should be refinished to specifications or replaced.
Lateral
Wunout Check (Figure 15)
1. Tighten wheel bearings until all the play is out of the
bearings. See Section 3C.
2. Remove caliper.
3. Fasten a dial indicator to the steering knuckle so that
the indicator button contacts the rotor about
25 mm (1
inch) from the rotor edge.
4. Zero the dial indicator.
5. Move the rotor one complete revolution, and observe
total indicated
runout (T.I.R.).
6. Readjust wheel bearings. See Section 3C.
Figure 14 Lining Inspection

5-16 BRAKES
Figure 15 Checking Lateral Runout
Lateral runout of the rotor should not be over 0.13 mm
(0.005-inch). A rotor that does not meet the lateral runout
specification should be resurfaced or replaced.
Rotor Tolerance and Surface Finish
In manufacturing the brake rotor, tolerances of the brak-
ing surfaces for flatness, thickness variation and lateral
runout are held very close. The maintenance of close toler-
ances on the shape of the braking surfaces is necessary to
prevent brake roughness. In addition to these tolerances, the surface finish must be
held to a specified range. The control of the braking surface
finish is necessary to avoid pulls and erratic performance
and to extend lining life.
Light scoring of the rotor surfaces not exceeding
0.38
mrn (0.015-inch) in depth, which may result from nor-
mal use, will not affect brake operation.
Refinishing Brake Rotors
All brake rotors have a minimum thickness dimension
cast into them. This dimension is the minimum wear dimen-
sion and not a refinish dimension. Do not use a brake rotor
that will not meet specifications. See Section
5F.
Since accurate control of the rotor tolerances is neces-
sary for proper performance of the disc brakes, machining
of the rotor should be done only with precision equipment.
When refinishing rotors, always use sharp cutting tools
or bits. Dull or worn tools leave a poor surface finish which
will affect initial braking performance. Vibration dampening
attachments should always be used when refinishing brak-
ing surfaces. These attachments eliminate tool chatter and
will result in better surface finish.
The optimum speed for refinishing braking surfaces is a
spindle speed of 200 rpm. Crossfeed for rough cutting
should range from 0.254-0.152 mm (0.010-0.006-inch) per
revolution. Finish cuts should be made at crossfeeds no
greater than 0.051 mm (0.002-inch) per revolution.
INSPECTING AND REFlNlSHlMG BRAKE
DRUMS
Whenever brake drums are removed, they should be
thoroughly cleaned and inspected for cracks, scores, deep
grooves, out-of-round and tapered conditions.
Cracked, Scored, or Grooved Drum
A cracked drum is unsafe for further service and must be
replaced. Do not attempt to weld a cracked drum.
Smooth any slight scores. Heavy or extensive scoring will
cause excessive brake lining wear, and it may be neces-
sary to resurface the brake drum to true up the braking
surface.
If the brake linings are slightly worn and the drum is
grooved, the drum should be polished with fine emery
cloth. The brake drums should not be turned since eliminat-
ing all the grooves in the drum and smoothing the ridges on
the lining would remove too much metal and lining. If left
alone, the grooves and ridges match and satisfactory serv-
ice can be obtained. If brake linings are replaced, a grooved drum should be
turned. Agrooved drum, if used with new lining, will not only
wear the lining, but will make it difficult, if not impossible, to
obtain efficient brake performance.
But-Of-Round or Tapered Drum
An out-of-round or tapered brake drum makes accurate
brake shoe adjustment impossible and will cause exces-
sive wear of other parts of the brake mechanism. An out-of-
round drum can also cause severely irregular tire tread
wear as well as a pulsating brake pedal. When the braking
surface of a brake drum exceeds the specification limits,
the drum should be turned to true up the braking surface.
Out-of-round, taper and brake drum wear can be accurately
measured with an inside micrometer fitted with proper
extension rods. When measuring a drum for out-of-round, taper and
wear, take measurements at the open and closed edges of
braking surface and at right angles to the edges.
Refinishing Brake Drums
If adrum is to be refinished, remove only enough metal to
obtain a true, smooth braking surface. If a drum does not
meet specifications when turned to the maximum
rebore
diameter shown in the specifications, shown in Section 5F,
it must be replaced. Removal of more metal will affect dissi-
pation of heat and may cause distortion of the drum.
All brake drums have a maximum diameter cast into
them. This diameter is the maximum wear diameter and not
a refinish diameter. Do not refinish a brake drum that will
not meet the specifications. Refer to specification chart,
Section 5F. When refinishing drums, always use sharp cutting tools
or bits. Dull or worn tools leave a poor surface finish which
will affect braking performance. Vibration dampening
attachments should always be used when refinishing brak-
ing surfaces. These attachments eliminate tool chatter and
will result in better surface finish.
Brake Drum Balance
During manufacture, weights are used to balance brake
drums. These weights must not be removed.
After drums are refinished or if difficulty is experienced in

I Liher Body 6 Push Rod Seat Reta~ner 2 Push Rod Seal 7 Plunger 3 Mater~ng Valve 8 Check Ball Spr~ng 4 Check Ball 9 Plunger Spr~ng 5 Check Ball Rete~ner 10 Olllna Flat
Figure 6A2-14 Valve Lifter
Disassembly
1. Hold the plunger down with a push rod, and
using the blade of a small screw driver, remove
the push rod seat retainer.
2. Remove the push rod seat and metering valve.
3. Remove the plunger, ball check valve assembly
and the plunger spring.
4. Remove the ball check valve and spring by prying
the ball retainer loose from the plunger with the
blade of a small screw driver.
Cleaning and Inspection
Thoroughly clean all parts in cleaning solvent,
and inspect them carefully. If any parts are damaged
or worn, the entire lifter assembly should be replaced.
If the lifter body wall is scuffed or worn, inspect the
cylinder block lifter bore. If the bottom of the lifter is
scuffed or worn, inspect the camshaft lobe. If the push
rod seat is scuffed or worn, inspect the push rod. An
additive containing EP lube, such as EOS, should
always be added to crankcase oil for run-in when any
new camshaft or lifters are installed. All damaged or
worn lifters should be replaced. For proper lifter
rotation during engine operation, lifter foot must be
convex.
Assembly
1. Place
the check ball on small hole in bottom of
the plunger.
2. Insert
check ball spring on seat in ball retainer
and place retainer over ball so that spring rests on
the ball. Carefully press the retainer into position
in plunger with the blade of a small screw driver.
3. Place the plunger spring over the ball retainer and
slide the lifter body over the spring and plunger,
being careful to line up the oil feed holes in the
lifter body and plunger.
4. Fill the assembly with SAE 10 oil, then insert the
end of a
1/8" drift pin into the plunger and press
down solid. Do not attempt to force or pump the
plunger. At this point, oil holes in the lifter body
and plunger assembly will be aligned.
5. Insert a 1/16" drift pin through both oil holes to
hold the plunger down against the lifter spring
tension.
6. Remove
the
1/8" drift pin, refill assembly with
SAE 10 oil.
7. Install the metering valve and push rod seat.
8. Install the push rod seat retainer, press down on
the push rod seat and remove the 1/16" drift pin
from the oil holes. The lifter is now completely
assembled, filled with oil and ready for
installation. Before installing lifters, coat the
bottom of the lifter with "Molykote" or its
equivalent.
CYLINDER HEAD (FIGURE 6A2-15)
Removal (Left)
Remove intake manifold as previously outlined.
Raise vehicle.
Drain engine block.
Disconnect exhaust pipe.
Remove dipstick tube attachment.
Lower vehicle.
Remove serpentine belt.
Remove A/C compressor and lay aside.
Remove
P/S pump and lay aside.
Loosen rocker arm until able to remove push rod.
Remove head bolts.
Remove head.
HEAD TORQUE SEQUENCE
/7 , 2 ing. Using a 12"
Figure 6A2-1'5 Cylinder Head Installation
Installation (Left)
The gasket surfaces on both head and cylinder
case deck must be clean of any foreign matter and free
of nicks of heavy scratches. Cylinder bolt threads in the
case and threads on the cylinder head bolts must be
clean. Dirt will affect bolt torque.
1. Place the gasket in position, over the dowel pins,
with the note "This Side Up" showing.
2. Install cylinder head.
3. Coat cylinder head bolt threads with sealer,
#1052080 or equivalent, and install bolts.

QA3-10 V-8 ENGINE
lnstallation
1. Install valve stem seal over valve stem and seat
against head.
2. Set
the valve spring and damper, oil shedder and
valve cap in place. Compress the spring with Tool
J-5892 and install oil seal in the lower groove of
the stem, making sure the seal is flat and not
twisted. A light coat of oil on the seal will help
prevent twisting.
3. Install
the valve locks and release the compressor
tool making sure the locks seat properly in the
upper groove of the valve stem. Grease may be
used to hold the locks in place while releasing the
compressor tool.
4. Using tool J-23994, apply vacuum to the valve
cap to make sure no air leaks past the seal.
5. Install spark plug and torque to 22 lb. ft.
(30N.m).
6. Install and adjust valve mechanism as previously
outlined.
VALVE LIFTERS
Hydraulic valve lifters very seldom require
attention. The lifters are extremely simple in design,
readjustments are not necessary, and servicing of the
lifters requires only that care and cleanliness be
exercised in the handling of parts.
Valve Lifter Diagnosis
1.
Momentarily Noisy When Car is Started:
This condition is normal. Oil drains from the
lifters which are holding the valves open when the
engine is not running. It will take a few seconds
for the lifter to fill after the engine is started.
2. Intermittently Noisy On Idle Only. Disappearing
When Engine Speed is Increased:
Intermittent clicking may be an indication of a
pitted check valve ball, or it may be caused by
dirt.
Correction: Clean the lifter and inspect. If check
valve ball is defective, replace lifter.
3. Noisy At Slow Idle Or With Hot Oil, Quiet With
Cold Oil Or As Engine Speed Is Increased:
High leak down rate. Replace suspect lifter.
4. Noisy At High Car Speeds And Quiet At Low
Speeds:
a. High oil level
- Oil level above the "Full"
mark allows crankshaft counterweights to
churn the oil into foam. When foam is
pumped into the lifters, they will become
noisy since a solid column of oil is required
for proper operation. Correction: Drain oil
inti1 proper level is obtained.
b. Low oil level - Oil level below the "Add"
mark allows the pump to pump air at high
speeds which results in noisy lifters.
Correction: Fill until proper oil level is
obtained.
c. Oil pan bent on bottom or pump screen
cocked or loose, replace or repair as
necessary. 5.
Noisy At Idle Becoming Louder As Engine Speed
Is Increased To 1500 rpm:
This noise is not connected with lifter
malfunction. It becomes most noticeable in the
car at 10 to 15 mph "1" (Low) range, or 30 to
35
mph "DM (Drive) range and is best described as
a
hashy sound. At slow idle, it may be entirely
gone or appear as a light ticking noise in one or
more valves. It is caused by one or more of the
following:
a. Badly worn or scuffed valve tip and rocker
arm pad.
b. Excessive valve stem to guide clearance.
c. Excessive valve seat
runout.
d. Off square valve spring.
e. Excessive valve face
runout.
f. Valve spring damper clicking on rotator.
Removal
1.
Remove intake manifold as previously outlined.
2. Remove valve mechanism as previously outlined.
3. Remove valve lifter retainer.
4. Remvoe valve lifter restrictor.
5. Remove valve lifters (Fig.
6A3-7). Place valve
lifters in a rack so that they may be reinstalled in
the same location.
Installation
1.
Coat roller of valve lifters with "Molykote" or its
equivalent and install valve lifters.
2. Install valve lifter restrictor.
3. Install valve lifter retainer.
4. Install intake manifold as previously outlined.
5. Install and adjust valve mechanism as outlined.
Disassembly
PLUNGER SPRING
Fig. 6A3-1 1 Hydraulic Valve Lifter
1. Hold the plunger down with a push rod, and
using the blade of a small screw driver, remove
the push rod seat retainer.
2. Remove the push rod seat and metering valve
(fig.
6A3- 1 1).

6C-4 ENGINE FUEL
to fully insert the unleaded gas nozzle will result in
gasoline splashing back out of the filler neck.
Fuel Gage Sending Unit
The fuel gage sending unit is attached to the top
of the fuel tank. It is held in place with a cam lock ring
and a gasket is used between the tank and sending unit.
Sending units have three hoses attached. One line
is for the fuel feed. The second line is connected to the
vapor canister, to keep fuel vapor from getting into the
air (see Section 6E). The third line is used as a fuel
return line to the tank.
On some sending units a wire is attached to the
unit. On others the connectors attach directly to the
sender.
When a fuel gage sending unit is removed always
make sure to install the gasket and any power or
ground leads that were removed.
DIAGNOSIS
Fuel system diagnostic procedures are located in
Section(s) 6E1 thru 6E3.
SERVICE PROCEDURES
If the fuel system is suspected of delivering an
improper amount of fuel, it should be inspected and
tested in the vehicle, as follows:
1. Make certain that there is fuel in the tank.
2. With the engine running, inspect for leaks at all
fuel feed pipe and hose connections from
fuel
tank to injection pump. Tighten any loose
connections. Inspect all hoses for flattening or
kinks which would restrict the flow of fuel. Air
leaks or restrictions on suction side of fuel pump
will seriously affect pump output.
FUEL SYSTEM PRESSURE RELIEF
CAUTION: To reduce risk of fire and
personal injury, it is necessary to
relieve duel system pressure before
servicing fuel system components. To
do this:
Remove "fuel pump" fuse from fuse
block in passenger compartment.
e Crank engine - engine will start and run
until fuel supply remaining in fuel lines is
consumed. Engage starter for
3.0
seconds to assure relief of any remaining
pressure.
e With ignition "OFF", replace duel pump
fuse.
Unless this procedure
is followed before
servicing fuel lines
or connections, fuel
spray could occur.
When repair to the fuel system has been
completed, start engine and check all connections that
were loosened for possible leaks.
Refer to Section 6E for additional diagnosis of
engine fuel system.
Fuel Pump Flow Test
1. Test fuel
pump by connecting hose from EFI fuel
feed line to a suitable unbreakable container.
Apply battery voltage to the fuel pump test
terminal (terminal
"G" of ALCL).
2. Fuel pump should supply
1/2 pint or more in 15
seconds.
3. If flow is below minimum, check for fuel
restriction. If there is no restriction, check pump
pressure.
Fuel System Pressure Test
This test must be performed when diagnosing the
fuel system.
CAUTION: To reduce the risk of fire
and personal injury, it is necessary to
relieve fuel system pressure before
servicing fuel system components on
the
TBI system. To do this:
s Remove "Fuel Pump" fuse from fuse block in
passenger compartment.
e Crank engine. Engine will start and run until fuel
remaining in fuel lines is consumed. Crank the
starter for three seconds to assure that any
remaining pressure is relieved.
e With the ignition off, replace the "Fuel Pump"
fuse.
1. Obtain two
sections of
3/8" steel tubing. Each
should be about 254 mm (10 inches) long.
I
Double-flare one end of each section.
2. Install a flare nut on each section. Connect each i
of the above sections of tubing into the "flare nut 1
to flare nut adapters" that are included in J-29658 i
Gage Adapters.
3. Attach the
pipe and adapter assemblies to the
J-29658 gage.
4. Hoist the car.
5. Disconnect
front fuel feed hose from the fuel pipe
on the body.
1
6. Install a
254 mm (10 inch) length of 3/8" fuel
hose onto the fuel feed pipe on the body. Attach 1
I the other end of the hose onto one of the sections
of pipe mentioned in Step 1. Secure the hose
connections with clamps.
7. Attach the front fuel feed hose onto the other
i
section of tubing mentioned in Step 1. Secure the I
hose connection with a clamp. I
8. Start
the engine and check for leaks. I 9. Observe
the fuel pressure reading. It should be 62
to 90
kPa (9 to 13 psi). If not, refer to the I
appropriate Emissions Section.
10. Depressurize
the fuel system and remove the gage I
with adapters. Reconnect the fuel feed hose to the
pipe and torque the clamp to
1.7 N.m (1 5 lb. in.).
11. Lower
the car. Start the engine and check for fuel
leaks.
Fuel System Pressure Test- MPFl
Fuel system diagnosis is in Section 6E3, Chart
A-7.