brakes DODGE RAM 2003 Service User Guide

HALF SHAFT
TABLE OF CONTENTS
page page
HALF SHAFT
CAUTION.............................11
DIAGNOSIS AND TESTING................11
REMOVAL.............................11
INSTALLATION.........................12
SPECIFICATIONS.......................12
SPECIAL TOOLS.......................12CV JOINT-OUTER
REMOVAL.............................13
INSTALLATION.........................13
CV JOINT-INNER
REMOVAL.............................16
INSTALLATION.........................16
HALF SHAFT
CAUTION
CAUTION:: Never grasp half shaft assembly by the
boots. This may cause the boot to pucker or crease
and reduce the service life of the boot.
Avoid over angulating or stroking the C/V joints
when handling the half shaft.
Half shafts exposed to battery acid, transmission
fluid, brake fluid, differential fluid or gasoline may
cause the boots to deteriorate.
DIAGNOSIS AND TESTING
Check for grease at the inboard and outboard C/V
joint. This is a sign of boot or boot clamp damage.
NOISE/VIBRATION IN TURNS
A clicking noise or a vibration in turns could be
caused by a damaged outer C/V or inner tripod joint
seal boot or seal boot clamps. This will result in the
loss/contamination of the joint grease, resulting in
inadequate lubrication of the joint. Noise could also
be caused by another component of the vehicle com-
ing in contact with the half shafts.
CLUNKING NOISE DURING ACCELERATION
This noise may be a result of a damaged or worn
C/V joint. A torn boot or loose/missing clamp on the
inner/outer joint which has allowed the grease to be
lost will damage the C/V joint.
SHUDDER/VIBRATION DURING ACCELERATION
This problem could be a result of a worn/damaged
inner tripod joint or a sticking tripod joint. Improper
wheel alignment may also cause a shudder or vibra-
tion.
VIBRATION AT HIGHWAY SPEEDS
This problem could be a result of out of balance
front tires or tire/wheel runout. Foreign material
(mud, etc.) packed on the backside of the wheel(s)
will also cause a vibration.
REMOVAL
(1) Loosen lug nuts and hub nut while the with
the vehicle brakes applied.
(2) Raise and support the vehicle.
(3) Remove wheel and tire assembly
(4) Remove half shaft hub nut.
(5) Remove brake caliper and rotor.
(6) Position hydraulic jack under lower suspension
arm and raise jack to unload rebound bumper.
(7) Remove lower shock absorber bolt.
(8) Remove upper ball joint nut and seperate ball
with Remover 8677 (Fig. 1).
Fig. 1 UPPER BALL JOINT SEPARATION
1 - UPPER CONTROL ARM
2 - REMOVER
3 - STEERING KNUCKLE
DRHALF SHAFT 3 - 11

(34) Zero dial indicator face to pointer.
(35) Push and hold ring gear downward while not
allowing the pinion gear to rotate. Dial indicator
reading should be between 0.12 mm (0.005 in.) and
0.20 mm (0.008 in.). If backlash is not within specifi-
cations transfer the necessary amount of shim thick-
ness from one side of the differential housing to the
other (Fig. 19).
(36) Verify differential case and ring gear runout
by measuring ring to pinion gear backlash at eight
locations around the ring gear. Readings should not
vary more than 0.05 mm (0.002 in.). If readings vary
more than specified, the ring gear or the differential
case is defective.
After the proper backlash is achieved, perform the
Gear Contact Pattern procedure.
GEAR CONTACT PATTERN
Gear tooth contact pattern is used to verify the cor-
rect running position of the ring and pinion gears.
This will produce low noise and long gear life. Gears
which are not positioned properly may be noisy and
have shorten gear life.
(1) Wipe clean each tooth of the ring gear.
(2) Apply gear marking compound to all of the ring
gear teeth.
(3) Verify bearing cap bolts are torque specifica-
tion.
(4) Apply the brakes lightly to create at 14 N´m
(10 ft. lbs.) pinion rotating torque.
(5) Rotate the pinion/pinion yoke 4 full revolutions
in each directions.
(6) Read gear tooth contact pattern:²Gear contact pattern correct (Fig. 20). Backlash
and pinion depth is correct.
²Ring gear too far away from pinion gear (Fig.
21). Decrease backlash by moving the ring closer to
the pinion gear.
²Ring gear too close to pinion gear (Fig. 22).
Increase backlash, by moving the ring away from the
pinion gear.
Fig. 19 BACKLASH SHIM ADJUSTMENT
Fig. 20 CORRECT CONTACT PATTERN
Fig. 21 INCORRECT BACKLASH
1 - COAST SIDE TOE
2 - DRIVE SIDE HEEL
Fig. 22 INCORRECT BACKLASH
1 - DRIVE SIDE TOE
2 - COAST SIDE HEEL
3 - 28 FRONT AXLE - C205FDR
FRONT AXLE - C205F (Continued)

(6) Install ring gear side adjuster lock and bolt. Do
not tighten adjuster lock bolt at this time.
(7) Tighten pinion gear side adjuster firmly
against the differential case bearing cup.
(8) Rotate the pinion several times to seat the dif-
ferential bearings.
(9) Loosen pinion gear side adjuster until it is no
longer in contact with the bearing cup, then tighten
it until it makes contact.
(10) Tighten pinion gear side adjuster an addi-
tional:
²New Bearings:6 Adjuster Holes
²Original Bearings:4 Adjuster Holes
(11) Install pinion gear side adjuster lock and bolt.
Do not tighten adjuster lock bolt at this time.
(12) Tighten bearing cap bolts to 85 N´m (63 ft.
lbs.).
(13) Tighten adjuster lock bolts to 25 N´m (18 ft.
lbs.).
(14) Measure ring gear backlash with a Dial Indi-
cator C-3339 and Dial Indicator Stud L-4438 at eight
points around the drive side of the ring gear (Fig. 6).
The backlash should be 0.08-0.25 mm (0.003-0.010
in) with a preferred backlash of 0.13-0.18 mm (0.005-
0.007 in).
NOTE: Backlash measurement should not vary
more than 0.05 mm (0.002 in) between measuring
points. If measurement does vary inspect the gears
for burrs, the differential case flange and ring gear
mounting.GEAR TOOTH CONTACT PATTERN
Gear tooth contact pattern is used to verify the cor-
rect running position of the ring and pinion gears.
This will produce low noise and long gear life. Gears
which are not positioned properly may be noisy and
have shortened gear life.
(1) Wipe clean each tooth of the ring gear.
(2) Apply gear marking compound to all of the ring
gear teeth.
(3) Verify bearing cap bolts are torque to specifica-
tion.
(4) Apply the brakes lightly to create a 14 N´m (10
ft. lbs.) pinion rotating torque.
(5) Rotate the pinion/pinion yoke 4 full revolutions
in each directions.
(6) Read gear tooth contact pattern:
²Gear contact pattern is correct (Fig. 7). Backlash
and pinion depth is correct.
²Ring gear too far away from pinion gear (Fig. 8).
Decrease backlash, by moving the ring closer to the
pinion gear using the adjusters.
Fig. 6 RING GEAR BACKLASH
1 - DIAL INDICATOR
2 - RING GEAR
Fig. 7 CORRECT CONTACT PATTERN
Fig. 8 INCORRECT BACKLASH
1 - COAST SIDE TOE
2 - DRIVE SIDE HEEL
DRFRONT AXLE - 9 1/4 AA 3 - 51
FRONT AXLE - 9 1/4 AA (Continued)

(3) Rotate the ring gear to the position of the least
backlash. Mark the gear so that all future backlash
measurements will be taken with the same gear
teeth meshed.
(4) Loosen the right-side, tighten the left-side
threaded adjuster. Obtain backlash of 0.076 to 0.102
mm (0.003-0.004 in.) with each adjuster tightened to
14 N´m (10 ft. lbs.). Seat the bearing cups with the
procedure described above.
(5) Tighten the differential bearing cap bolts 136
N´m (100 ft. lbs.).
(6) Tighten the right-side threaded adjuster to 102
N´m (75 ft. lbs.). Seat the bearing cups with the pro-
cedure described above. Continue to tighten the
right-side adjuster and seat bearing cups until the
torque remains constant at 102 N´m (75 ft. lbs.)
(7) Measure the ring gear backlash. The range of
backlash is 0.15 to 0.203 mm (0.006 to 0.008 in.).
(8) Continue increasing the torque at the right-
side threaded adjuster until the specified backlash is
obtained.
NOTE: The left-side threaded adjuster torque
should have approximately 102 N´m (75 ft. lbs.). If
the torque is considerably less, the complete
adjustment procedure must be repeated.
(9) Tighten the left-side threaded adjuster until
102 N´m (75 ft. lbs.) torque is indicated. Seat the
bearing rollers with the procedure described above.
Do this until the torque remains constant.
(10) Install the threaded adjuster locks and
tighten the lock screws to 10 N´m (90 in. lbs.).GEAR CONTACT PATTERN
Gear tooth contact pattern is used to verify the cor-
rect running position of the ring and pinion gears.
This will produce low noise and long gear life. Gears
which are not positioned properly may be noisy and
have shorten gear life.
(1) Wipe clean each tooth of the ring gear.
(2) Apply gear marking compound to all of the ring
gear teeth.
(3) Verify bearing cap bolts are torque specifica-
tion.
(4) Apply parking brakes lightly to create at 14
N´m (10 ft. lbs.) pinion rotating torque.
(5) Rotate the pinion/pinion yoke 4 full revolutions
in each directions.
(6) Read gear tooth contact pattern:
²Gear contact pattern is correct (Fig. 9). Backlash
and pinion depth is correct.
²Ring gear too far away from pinion gear (Fig.
10). Decrease backlash, by moving the ring closer to
the pinion gear using the adjusters.
Fig. 8 RING GEAR BACKLASH
1 - DIAL INDICATOR
2 - RING GEAR
3 - EXCITER RING
Fig. 9 CORRECT CONTACT PATTERN
Fig. 10 INCORRECT BACKLASH
1 - COAST SIDE TOE
2 - DRIVE SIDE HEEL
DRREAR AXLE - 9 1/4 3 - 77
REAR AXLE - 9 1/4 (Continued)

(friction modifier) should be added after repair ser-
vice or during a lubricant change.
After changing the lubricant, drive the vehicle and
make 10 to 12 slow, figure-eight turns. This maneu-
ver will pump lubricant through the clutches. This
will correct the condition in most instances. If the
chatter persists, clutch damage could have occurred.
DIFFERENTIAL TEST
The differential can be tested without removing the
differential case by measuring rotating torque. Make
sure brakes are not dragging during this measure-
ment.
(1) Place blocks in front and rear of both front
wheels.
(2) Raise one rear wheel until it is completely off
the ground.
(3) Engine off, transmission in neutral, and park-
ing brake off.
(4) Remove wheel and bolt Special Tool 6790 or
equivalent tool to studs.
(5) Use torque wrench on special tool to rotate
wheel and read rotating torque (Fig. 37).
(6) If rotating torque is less than 41 N´m (30 ft.
lbs.) or more than 271 N´m (200 ft. lbs.) on either
wheel the unit should be serviced.
DISASSEMBLY
(1) Clamp Fixture 6965 in a vise and position the
differential case on the fixture (Fig. 38).
(2) Remove ring gear if the ring gear is to be
replaced.
(3) Remove pinion gear mate shaft lock screw.
(4) Remove pinion gear mate shaft with a drift and
hammer.(5) Install and lubricate Step Plate C-6960-3 (Fig.
39).
(6) Assemble Threaded Adapter C-6960-1 into top
side gear. Thread Forcing Screw C-6960-4 into
adapter until it becomes centered in adapter plate.
Fig. 37 ROTATING TORQUE TEST
1 - SPECIAL TOOL WITH BOLT IN CENTER HOLE
2 - TORQUE WRENCH
Fig. 38 DIFFERENTIAL CASE FIXTURE
1 - HOLDING FIXTURE
2 - VISE
3 - DIFFERENTIAL
Fig. 39 STEP PLATE
1 - LOWER SIDE GEAR
2 - DIFFERENTIAL CASE
3 - DISC
3 - 90 REAR AXLE-91/4DR
DIFFERENTIAL-TRAC-LOK (Continued)

(12) Tighten bearing cap bolts to 115 N´m (85 ft.
lbs.).
(13) Tighten adjuster lock bolts to 33 N´m (24 ft.
lbs.).
(14) Measure ring gear backlash with a Dial Indi-
cator C-3339 and Dial Indicator Stud L-4438 at eight
points around the drive side of the ring gear (Fig. 7).
The backlash should be 0.08-0.25 mm (0.003-0.010
in) with a preferred backlash of 0.13-0.18 mm (0.005-
0.007 in).
NOTE: Backlash measurement should not vary
more than 0.05 mm (0.002 in) between measuring
points. If measurement does vary inspect the gears
for burrs, the differential case flange and ring gear
mounting.
GEAR TOOTH CONTACT PATTERN
Gear tooth contact pattern is used to verify the cor-
rect running position of the ring and pinion gears.
This will produce low noise and long gear life. Gears
which are not positioned properly may be noisy and
have shorten gear life.
(1) Wipe clean each tooth of the ring gear.
(2) Apply gear marking compound to all of the ring
gear teeth.
(3) Verify bearing cap bolts are torque specifica-
tion.
(4) Apply parking brakes lightly to create at 14
N´m (10 ft. lbs.) pinion rotating torque.
(5) Rotate the pinion/pinion yoke 4 full revolutions
in each directions.
(6) Read gear tooth contact pattern:²Gear contact pattern correct (Fig. 8). Backlash
and pinion depth is correct.
²Ring gear too far away from pinion gear (Fig. 9).
Decrease the backlash, by moving the ring closer to
the pinion gear using the adjusters.
²Ring gear too close to pinion gear (Fig. 10).
Increase the backlash, by moving the ring away from
the pinion gear using the adjusters.
Fig. 7 RING GEAR BACKLASH
1 - DIAL INDICATOR
2 - RING GEAR
Fig. 8 CORRECT CONTACT PATTERN
Fig. 9 INCORRECT BACKLASH
1 - COAST SIDE TOE
2 - DRIVE SIDE HEEL
Fig. 10 INCORRECT BACKLASH
1 - DRIVE SIDE TOE
2 - COAST SIDE HEEL
3 - 106 REAR AXLE - 10 1/2 AADR
REAR AXLE - 10 1/2 AA (Continued)

(12) Tighten bearing cap bolts to 115 N´m (85 ft.
lbs.).
(13) Tighten adjuster lock bolts to 33 N´m (24 ft.
lbs.).
(14) Measure ring gear backlash with a Dial Indi-
cator C-3339 and Dial Indicator Stud L-4438 at eight
points around the drive side of the ring gear (Fig. 7).
The backlash should be 0.08-0.25 mm (0.003-0.010
in) with a preferred backlash of 0.13-0.18 mm (0.005-
0.007 in).
NOTE: Backlash measurement should not vary
more than 0.05 mm (0.002 in) between measuring
points. If measurement does vary inspect the gears
for burrs, the differential case flange and ring gear
mounting.
GEAR TOOTH CONTACT PATTERN
Gear tooth contact pattern is used to verify the cor-
rect running position of the ring and pinion gears.
This will produce low noise and long gear life. Gears
which are not positioned properly may be noisy and
have shorten gear life.
(1) Wipe clean each tooth of the ring gear.
(2) Apply gear marking compound to all of the ring
gear teeth.
(3) Verify bearing cap bolts are torque specifica-
tion.
(4) Apply parking brakes lightly to create at 14
N´m (10 ft. lbs.) pinion rotating torque.
(5) Rotate the pinion/pinion yoke 4 full revolutions
in each directions.
(6) Read gear tooth contact pattern:²Gear contact pattern correct (Fig. 8). Backlash
and pinion depth is correct.
²Ring gear too far away from pinion gear (Fig. 9).
Decrease backlash, by moving the ring closer to the
pinion gear using the adjusters.
²Ring gear too close to pinion gear (Fig. 10).
Increase backlash, by moving the ring away from the
pinion gear using the adjusters.
Fig. 7 RING GEAR BACKLASH
1 - DIAL INDICATOR
2 - RING GEAR
Fig. 8 CORRECT CONTACT PATTERN
Fig. 9 INCORRECT BACKLASH
1 - COAST SIDE TOE
2 - DRIVE SIDE HEEL
Fig. 10 INCORRECT BACKLASH
1 - DRIVE SIDE TOE
2 - COAST SIDE HEEL
DRREAR AXLE - 11 1/2 AA 3 - 133
REAR AXLE - 11 1/2 AA (Continued)

BRAKES
TABLE OF CONTENTS
page page
BRAKES - BASE........................... 1BRAKES - ABS........................... 39
BRAKES - BASE
TABLE OF CONTENTS
page page
BRAKES - BASE
DIAGNOSIS AND TESTING - BASE BRAKE
SYSTEM.............................2
STANDARD PROCEDURE
STANDARD PROCEDURE - MANUAL
BLEEDING............................5
STANDARD PROCEDURE - PRESSURE
BLEEDING............................5
SPECIAL TOOLS
BASE BRAKES........................5
ADJUSTABLE PEDAL SWITCH
REMOVAL.............................6
INSTALLATION..........................6
HYDRAULIC/MECHANICAL
SPECIFICATIONS
SPECIFICATIONS - TORQUE CHART.......6
BASE BRAKE.........................7
BRAKE LINES
STANDARD PROCEDURE
STANDARD PROCEDURE - DOUBLE
INVERTED FLARING....................7
STANDARD PROCEDURE - ISO FLARING . . . 7
REMOVAL
REMOVAL - REAR BRAKE HOSE..........8
REMOVAL - REAR TUBE / HOSE
ASSEMBLY...........................8
REMOVAL - FRONT HOSE...............9
INSTALLATION
INSTALLATION - REAR BRAKE HOSE......9
INSTALLATION - REAR TUBE / HOSE
ASSEMBLY...........................9
INSTALLATION - FRONT BRAKE HOSE.....9
BRAKE PADS/SHOES
REMOVAL.............................10
INSTALLATION.........................10
DISC BRAKE CALIPERS
DESCRIPTION.........................11OPERATION...........................12
REMOVAL
REMOVAL - REAR.....................12
REMOVAL - FRONT....................12
DISASSEMBLY.........................13
INSPECTION..........................14
ASSEMBLY............................15
INSTALLATION
INSTALLATION - REAR.................16
INSTALLATION - FRONT................16
DISC BRAKE CALIPER ADAPTER
REMOVAL
REMOVAL - REAR.....................16
REMOVAL - FRONT....................16
INSTALLATION
INSTALLATION - REAR.................17
INSTALLATION - FRONT................17
DISC BRAKE CALIPER ADAPTER MOUNT
REMOVAL - REAR......................17
INSTALLATION.........................17
FLUID
DIAGNOSIS AND TESTING - BRAKE FLUID
CONTAMINATION.....................18
STANDARD PROCEDURE - BRAKE FLUID
LEVEL..............................18
SPECIFICATIONS
BRAKE FLUID........................18
FLUID RESERVOIR
REMOVAL.............................19
INSTALLATION.........................19
BRAKE JUNCTION BLOCK
REMOVAL.............................19
INSTALLATION.........................19
MASTER CYLINDER
DESCRIPTION.........................19
OPERATION...........................20
DRBRAKES 5 - 1

DIAGNOSIS AND TESTING - MASTER
CYLINDER/POWER BOOSTER...........20
STANDARD PROCEDURE - MASTER
CYLINDER BLEEDING..................20
REMOVAL
REMOVAL - ALL EXCEPT HYDROBOOST . . . 21
REMOVAL - HYDROBOOST.............21
INSTALLATION
INSTALLATION - ALL EXCEPT
HYDROBOOST.......................22
INSTALLATION - HYDROBOOST..........22
PEDAL
DESCRIPTION.........................22
OPERATION...........................22
REMOVAL.............................23
INSTALLATION.........................23
ADJUSTABLE PEDAL MOTOR
DESCRIPTION.........................24
REMOVAL.............................24
INSTALLATION.........................24
POWER BRAKE BOOSTER
DESCRIPTION.........................25
OPERATION...........................25
REMOVAL.............................25
INSTALLATION.........................25
HYDRO-BOOST BRAKE BOOSTER
DIAGNOSIS AND TESTING - HYDRAULIC
BOOSTER...........................25
STANDARD PROCEDURE - BLEEDING......27
REMOVAL.............................27
INSTALLATION.........................27
ROTORS
REMOVAL
REMOVAL - REAR.....................28
REMOVAL - FRONT....................28
INSTALLATION
INSTALLATION - REAR.................28
INSTALLATION - FRONT................29SUPPORT PLATE
REMOVAL.............................29
INSTALLATION.........................29
PARKING BRAKE
DESCRIPTION.........................30
OPERATION...........................30
CABLES
REMOVAL
REMOVAL - FRONT PARKING BRAKE
CABLE..............................31
REMOVAL - REAR PARK BRAKE CABLE . . . 31
REMOVAL - RIGHT REAR CABLE.........31
REMOVAL - LEFT REAR CABLE..........32
INSTALLATION
INSTALLATION - FRONT PARKING BRAKE
CABLE..............................32
INSTALLATION - REAR PARK BRAKE
CABLE..............................32
INSTALLATION - RIGHT REAR CABLE.....32
INSTALLATION - LEFT REAR CABLE......33
SHOES
REMOVAL.............................33
CLEANING - REAR DRUM IN HAT BRAKE....33
INSPECTION - REAR DRUM IN HAT BRAKE . . 33
INSTALLATION.........................34
ADJUSTMENTS
ADJUSTMENT - PARKING BRAKE SHOES . . 34
ADJUSTMENT - WITH ADJUSTING TOOL . . . 36
PEDAL
REMOVAL.............................36
INSTALLATION.........................36
CABLE TENSIONER
ADJUSTMENTS
ADJUSTMENT........................37
RELEASE HANDLE
REMOVAL.............................38
INSTALLATION.........................38
BRAKES - BASE
DIAGNOSIS AND TESTING - BASE BRAKE
SYSTEM
Base brake components consist of the brake shoes,
calipers, wheel cylinders, brake drums, rotors, brake
lines, master cylinder, booster, and parking brake
components.
Brake diagnosis involves determining if the prob-
lem is related to a mechanical, hydraulic, or vacuum
operated component.
The first diagnosis step is the preliminary check.
PRELIMINARY BRAKE CHECK
(1) Check condition of tires and wheels. Damaged
wheels and worn, damaged, or underinflated tires
can cause pull, shudder, vibration, and a condition
similar to grab.(2) If complaint was based on noise when braking,
check suspension components. Jounce front and rear
of vehicle and listen for noise that might be caused
by loose, worn or damaged suspension or steering
components.
(3) Inspect brake fluid level and condition. Note
that the brake reservoir fluid level will decrease in
proportion to normal lining wear.Also note that
brake fluid tends to darken over time. This is
normal and should not be mistaken for contam-
ination.
(a) If fluid level is abnormally low, look for evi-
dence of leaks at calipers, wheel cylinders, brake
lines, and master cylinder.
(b) If fluid appears contaminated, drain out a
sample to examine. System will have to be flushed
if fluid is separated into layers, or contains a sub-
stance other than brake fluid. The system seals
5 - 2 BRAKES - BASEDR

and cups will also have to be replaced after flush-
ing. Use clean brake fluid to flush the system.
(4) Check parking brake operation. Verify free
movement and full release of cables and pedal. Also
note if vehicle was being operated with parking
brake partially applied.
(5) Check brake pedal operation. Verify that pedal
does not bind and has adequate free play. If pedal
lacks free play, check pedal and power booster for
being loose or for bind condition. Do not road test
until condition is corrected.
(6) Check booster vacuum check valve and hose.
(7) If components checked appear OK, road test
the vehicle.
ROAD TESTING
(1) If complaint involved low brake pedal, pump
pedal and note if it comes back up to normal height.
(2) Check brake pedal response with transmission
in Neutral and engine running. Pedal should remain
firm under constant foot pressure.
(3) During road test, make normal and firm brake
stops in 25-40 mph range. Note faulty brake opera-
tion such as low pedal, hard pedal, fade, pedal pulsa-
tion, pull, grab, drag, noise, etc.
(4) Attempt to stop the vehicle with the parking
brake only and note grab, drag, noise, etc.
PEDAL FALLS AWAY
A brake pedal that falls away under steady foot
pressure is generally the result of a system leak. The
leak point could be at a brake line, fitting, hose, or
caliper/wheel cylinder. If leakage is severe, fluid will
be evident at or around the leaking component.
Internal leakage (seal by-pass) in the master cylin-
der caused by worn or damaged piston cups, may
also be the problem cause.
An internal leak in the ABS or RWAL system may
also be the problem with no physical evidence.
LOW PEDAL
If a low pedal is experienced, pump the pedal sev-
eral times. If the pedal comes back up worn linings,
rotors, drums, or rear brakes out of adjustment are
the most likely causes. The proper course of action is
to inspect and replace all worn component and make
the proper adjustments.
SPONGY PEDAL
A spongy pedal is most often caused by air in the
system. However, thin brake drums or substandard
brake lines and hoses can also cause a spongy pedal.
The proper course of action is to bleed the system,
and replace thin drums and substandard quality
brake hoses if suspected.HARD PEDAL OR HIGH PEDAL EFFORT
A hard pedal or high pedal effort may be due to
lining that is water soaked, contaminated, glazed, or
badly worn. The power booster or check valve could
also be faulty.
PEDAL PULSATION
Pedal pulsation is caused by components that are
loose, or beyond tolerance limits.
The primary cause of pulsation are disc brake
rotors with excessive lateral runout or thickness vari-
ation, or out of round brake drums. Other causes are
loose wheel bearings or calipers and worn, damaged
tires.
NOTE: Some pedal pulsation may be felt during
ABS activation.
BRAKE DRAG
Brake drag occurs when the lining is in constant
contact with the rotor or drum. Drag can occur at one
wheel, all wheels, fronts only, or rears only.
Drag is a product of incomplete brake shoe release.
Drag can be minor or severe enough to overheat the
linings, rotors and drums.
Minor drag will usually cause slight surface char-
ring of the lining. It can also generate hard spots in
rotors and drums from the overheat-cool down pro-
cess. In most cases, the rotors, drums, wheels and
tires are quite warm to the touch after the vehicle is
stopped.
Severe drag can char the brake lining all the way
through. It can also distort and score rotors and
drums to the point of replacement. The wheels, tires
and brake components will be extremely hot. In
severe cases, the lining may generate smoke as it
chars from overheating.
Common causes of brake drag are:
²Seized or improperly adjusted parking brake
cables.
²Loose/worn wheel bearing.
²Seized caliper or wheel cylinder piston.
²Caliper binding on corroded bushings or rusted
slide surfaces.
²Loose caliper mounting.
²Drum brake shoes binding on worn/damaged
support plates.
²Mis-assembled components.
²Long booster output rod.
If brake drag occurs at all wheels, the problem
may be related to a blocked master cylinder return
port, or faulty power booster (binds-does not release).
BRAKE FADE
Brake fade is usually a product of overheating
caused by brake drag. However, brake overheating
DRBRAKES - BASE 5 - 3
BRAKES - BASE (Continued)