wheel DODGE RAM 2001 Service Repair Manual

Condition Possible Causes Correction
Axle Overheating 1. Lubricant level low. 1. Fill differential to correct level.
2. Improper grade of lubricant. 2. Fill differential with the correct fluid
type and quantity.
3. Bearing pre-loads too high. 3. Re-adjust bearing pre-loads.
4. Insufficient ring gear backlash. 4. Re-adjust ring gear backlash.
Gear Teeth Broke 1. Overloading. 1. Replace gears. Examine other gears
and bearings for possible damage.
2. Erratic clutch operation. 2. Replace gears and examine the
remaining parts for damage. Avoid
erratic clutch operation.
3. Ice-spotted pavement. 3. Replace gears and examine
remaining parts for damage.
4. Improper adjustments. 4. Replace gears and examine
remaining parts for damage. Ensure ring
gear backlash is correct.
Axle Noise 1. Insufficient lubricant. 1. Fill differential with the correct fluid
type and quantity.
2. Improper ring gear and pinion
adjustment.2. Check ring gear and pinion contact
pattern. Adjust backlash or pinion depth.
3. Unmatched ring gear and pinion. 3. Replace gears with a matched ring
gear and pinion.
4. Worn teeth on ring gear and/or
pinion.4. Replace ring gear and pinion.
5. Loose pinion bearings. 5. Adjust pinion bearing pre-load.
6. Loose differential bearings. 6. Adjust differential bearing pre-load.
7. Mis-aligned or sprung ring gear. 7. Measure ring gear run-out. Replace
components as necessary.
8. Loose differential bearing cap bolts. 8. Inspect differential components and
replace as necessary. Ensure that the
bearing caps are torqued tot he proper
specification.
9. Housing not machined properly. 9. Replace housing.
REMOVAL
(1) Raise and support the vehicle.
(2) Position a suitable lifting device under the
axle.
(3) Secure axle to device.
(4) Remove the wheels and tires.
(5) Secure brake drums to the axle shaft.
(6) Remove the RWAL sensor from the differential
housing, if necessary. Refer to 5 Brakes for proce-
dures.
(7) Disconnect the brake hose at the axle junction
block. Do not disconnect the brake hydraulic lines at
the wheel cylinders. Refer to 5 Brakes for procedures.(8) Disconnect the parking brake cables and cable
brackets.
(9) Disconnect the vent hose from the axle shaft
tube.
(10) Mark the propeller shaft and companion
flange for installation alignment reference.
(11) Remove propeller shaft.
(12) Disconnect shock absorbers from axle.
(13) Remove the spring clamps and spring brack-
ets. Refer to 2 Suspension for procedures.
(14) Separate the axle from the vehicle.
BR/BEREAR AXLE - 286RBI 3 - 173
REAR AXLE - 286RBI (Continued)

INSTALLATION
(1) Raise the axle with lifting device and align to
the leaf spring centering bolts.
(2) Install the spring clamps and spring brackets.
Refer to 2 Suspension for procedures.
(3) Install shock absorbers and tighten nuts to 82
N´m (60 ft. lbs.).
(4) Install the RWAL sensor to the differential
housing, if necessary. Refer to 5 Brakes for proce-
dures.
(5) Connect the parking brake cables and cable
brackets.
(6) Install the brake drums. Refer to 5 Brakes for
procedures.
(7) Connect the brake hose to the axle junction
block. Refer to 5 Brakes for procedures.
(8) Install axle vent hose.
(9) Align propeller shaft and pinion companion
flange reference marks. Install the companion flange
bolts. Tighten to 108 N´m (80 ft. lbs.).
(10) Install the wheels and tires.
(11) Add gear lubricant, if necessary. Refer to
Specifications for lubricant requirements.
(12) Remove lifting device from axle and lower the
vehicle.
ADJUSTMENTS
Ring and pinion gears are supplied as matched
sets only. The identifying numbers for the ring and
pinion gear are etched into the face of each gear (Fig.
4). A plus (+) number, minus (±) number or zero (0) is
etched into the face of the pinion gear. This number
is the amount (in thousandths of an inch) the depth
varies from the standard depth setting of a pinion
etched with a (0). The standard setting from the cen-
ter line of the ring gear to the back face of the pinion
is 147.625 mm (5.812 in.). The standard depth pro-
vides the best teeth contact pattern. Refer to Back-
lash and Contact Pattern Analysis Paragraph in this
section for additional information.
Compensation for pinion depth variance is
achieved with select shims. The shims are placed
under the inner pinion bearing cone (Fig. 5).
If a new gear set is being installed, note the depth
variance etched into both the original and replace-
ment pinion gear. Add or subtract the thickness of
the original depth shims to compensate for the differ-
ence in the depth variances. Refer to the Depth Vari-
ance charts.
Note where Old and New Pinion Marking columns
intersect. Intersecting figure represents plus or
minus amount needed.
Note the etched number on the face of the drive
pinion gear (±1, ±2, 0, +1, +2, etc.). The numbers rep-
resent thousands of an inch deviation from the stan-dard. If the number is negative, add that value to the
required thickness of the depth shim(s). If the num-
ber is positive, subtract that value from the thickness
of the depth shim(s). If the number is 0 no change is
necessary. Refer to the Pinion Gear Depth Variance
Chart.
Fig. 4 Pinion Gear ID Numbers
1 - PRODUCTION NUMBERS
2 - PINION GEAR DEPTH VARIANCE
3 - GEAR MATCHING NUMBER
Fig. 5 Adjustment Shim Locations
1 - PINION BEARING PRELOAD SHIM
2 - DIFFERENTIAL BEARING SHIM
3 - PINION GEAR DEPTH SHIM
3 - 174 REAR AXLE - 286RBIBR/BE
REAR AXLE - 286RBI (Continued)

AXLE SHAFTS
REMOVAL
(1) Remove the axle shaft flange bolts.
(2) Slide the axle shaft out from the axle tube.
INSTALLATION
(1) Clean the gasket contact surface area on the
flange with an appropriate solvent. Install a new
flange gasket and slide the axle shaft into the tube.
(2) Install the bolts and tighten to 129 N´m (95 ft.
lbs.).
AXLE BEARINGS
REMOVAL
(1) Remove wheel and tire assembly.
(2) Remove brake drum.
(3) Remove the axle shaft.
(4) Remove the lock wedge and adjustment nut.
Use Socket DD-1241±JD to remove the adjustment
nut.
(5) Remove the hub assembly. The outer axle bear-
ing will slide out as the hub is being removed.
(6) Remove inner grease seal and discard. Use
Installer 5064 and Handle C-4171 to drive grease
seal and inner axle bearing from the hub.
(7) Remove the bearing cups from the hub bore.
Use a brass drift, or an appropriate removal tool, to
tap out the cups.
INSTALLATION
(1) Thoroughly clean both axle bearings and inte-
rior of the hub with an appropriate cleaning solvent.
(2) Install the bearing cups. Use Installer 8153
and Handle C-4171 to install the bearing cups.
(3) Apply lubricant to surface area of the bearing
cup.
(4) Install the inner axle bearing in the hub.
(5) Install a new bearing grease seal. Use Installer
8152 and Handle C-4171 to install the grease seal.
(6) Inspect the bearing and seal contact surfaces
on the axle tube spindle for burrs and/or roughness.
Remove all the rough contact surfaces from the axle
spindle. Apply a coating of multi-purpose NLGI,
grade 2, EP-type lubricant to the axle.
CAUTION: Use care to prevent the bearing grease
seal from contacting the axle tube spindle threads
during installation. Otherwise, the seal could be
damaged.
(7) Carefully slide the hub onto the axle.
(8) Install the outer axle bearing.(9) Install the hub bearing adjustment nut. Use
Socket DD-1241±JD to install the adjustment nut.
(10) Tighten the adjustment nut to 163-190 N´m
(120-140 ft. lbs.) while rotating the wheel.
(11) Loosen the adjustment nut 1/8 of-a-turn to
provide 0.001-inch to 0.010-inch wheel bearing end
play.
(12) Tap the locking wedge into the spindle key-
way and adjustment nut. Try to ensure that the lock-
ing wedge is installed into a new position in the
adjustment nut.
(13) Install the axle shaft.
(14) Install the brake drum.
(15) Install the wheel and tire assembly.
PINION SEAL
REMOVAL
(1) Raise and support the vehicle.
(2) Scribe a mark on the universal joint, pinion
yoke, and pinion shaft for reference.
(3) Disconnect the propeller shaft from the pinion
yoke. Secure the propeller shaft in an upright posi-
tion to prevent damage to the rear universal joint.
(4) Remove the wheel and tire assemblies.
(5) Remove the brake drums to prevent any drag.
The drag may cause a false bearing preload torque
measurement.
(6) Rotate the pinion yoke three or four times.
(7) Measure the amount of torque necessary to
rotate the pinion gear with a (in. lbs.) dial-type
torque wrench. Record the torque reading for instal-
lation reference.
(8) Hold the yoke with Wrench 6719. Remove the
pinion shaft nut and washer.
(9) Remove the yoke with Remover C-452 (Fig. 22).
(10) Remove the pinion shaft seal with suitable
pry tool or slide-hammer mounted screw.
INSTALLATION
(1) Clean the seal contact surface in the housing
bore.
(2) Examine the splines on the pinion shaft for
burrs or wear. Remove any burrs and clean the shaft.
(3) Inspect pinion yoke for cracks, worn splines
and worn seal contact surface. Replace yoke if neces-
sary.
NOTE: The outer perimeter of the seal is pre-coated
with a special sealant. An additional application of
sealant is not required.
(4) Apply a light coating of gear lubricant on the
lip of pinion seal.
(5) Install new pinion shaft seal with an appropri-
ate Installer.
BR/BEREAR AXLE - 286RBI 3 - 185

NOTE: The seal is correctly installed when the seal
flange contacts the face of the differential housing
flange.
(6) Position pinion yoke on the end of the shaft
with the reference marks aligned.
(7) Seat yoke on pinion shaft with Installer D-191
and Yoke Holder 6719 (Fig. 23).
(8) Remove the tools and install the pinion yoke
washer and nut.
(9) Hold pinion yoke with Yoke Holder 6719 and
tighten shaft nut to 597 N´m (440 ft. lbs.) (Fig. 24).
Rotate pinion shaft several revolutions to ensure the
bearing rollers are seated.
(10) Rotate the pinion shaft using an inch pound
torque wrench. Rotating resistance torque should be
equal to the reading recorded, plus a small amount
for the drag the new seal will have (Fig. 25).
NOTE: The bearing rotating torque should be con-
stant during a complete revolution of the pinion. If
the rotating torque varies, this indicates a binding
condition.
(11) Install the propeller shaft with the installa-
tion reference marks aligned.
(12) Tighten the universal joint yoke clamp screws
to 19 N´m (14 ft. lbs.).
(13) Install the brake drums.
(14) Add gear lubricant to the differential housing,
if necessary. Refer to the Lubricant Specifications for
gear lubricant requirements.
(15) Install wheel and tire assemblies and lower
the vehicle.
Fig. 22 Yoke Removal
1 - PINION YOKE
2 - REMOVER C452
Fig. 23 Yoke Installation
1 - YOKE INSTALLER
2 - YOKE HOLDER
Fig. 24 Tightening Pinion Shaft Nut
1 - DIFFERENTIAL HOUSING
2 - YOKE HOLDER
3 - TORQUE WRENCH
3 - 186 REAR AXLE - 286RBIBR/BE
PINION SEAL (Continued)

(14) Remove support and lower vehicle.
DIFFERENTIAL - TRAC-LOK
DIAGNOSIS AND TESTING - TRAC-LOKY
The most common problem is a chatter noise when
turning corners. Before removing a Trac-lokyunit
for repair, drain, flush and refill the axle with the
specified lubricant. A container of Mopar Trac-loky
Lubricant (friction modifier) should be added after
repair service 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. 35).
(6) If rotating torque is less than 22 N´m (30 ft.
lbs.) or more than 271 N´m (200 ft. lbs.) on either
wheel the unit should be serviced.
DISASSEMBLY
The Trac-Lokydifferential on this axle has a one-
piece cross shaft and uses one dished disc, regular 5
disc and 7 plates.
NOTE: Pay attention to the clutch pack arrangement
during disassembly. Note the direction of the con-
cave and convex side of the plates and discs.
(1) Mark the ring gear half and cover half for
installation reference (Fig. 36).
(2) Remove case attaching bolts and remove the
button cover half (Fig. 37).
(3) Remove top clutch pack.
(4) Remove top side gear clutch ring.
(5) Remove top side gear.
(6) Remove pinion mate gears and cross shaft.
(7) Remove the same parts listed above from the
ring gear flange half of the case. Keep these parts
with the flange cover half for installation in their
original positions.
ASSEMBLY
The Trac-Lokydifferential for this axle has a one-
piece cross shaft and uses one dished disc, 5 regular
disc and 7 plates for each clutch pack.
NOTE: The clutch discs are replaceable as com-
plete sets only. If one clutch disc pack is damaged,
both packs must be replaced.
Fig. 34 Differential Cover
1 - SEALANT SURFACE
2 - SEALANT
3 - SEALANT THICKNESS
Fig. 35 Trac-lokYTest - Typical
3 - 190 REAR AXLE - 286RBIBR/BE
DIFFERENTIAL (Continued)

BRAKES
TABLE OF CONTENTS
page page
BRAKES - BASE
SPECIFICATIONS.........................2
SPECIAL TOOLS..........................4
HYDRAULIC/MECHANICAL
DESCRIPTION............................4
WARNING.............................5
DIAGNOSIS AND TESTING..................5
BASE BRAKE SYSTEM...................5
STANDARD PROCEDURE...................7
MANUAL BLEEDING.....................7
PRESSURE BLEEDING...................8
BRAKE LINES
STANDARD PROCEDURE...................8
DOUBLE INVERTED FLARING..............8
ISO FLARING...........................8
COMBINATION VALVE
DESCRIPTION............................9
OPERATION.............................9
DIAGNOSIS AND TESTING..................9
COMBINATION VALVE....................9
REMOVAL..............................10
INSTALLATION...........................10
DISC BRAKE CALIPERS
REMOVAL..............................10
DISASSEMBLY...........................11
CLEANING..............................12
INSPECTION............................12
ASSEMBLY.............................12
INSTALLATION...........................13
FLUID
DIAGNOSIS AND TESTING.................14
BRAKE FLUID CONTAMINATION...........14
STANDARD PROCEDURE..................14
BRAKE FLUID LEVEL....................14
SPECIFICATIONS........................15
FLUID RESERVOIR
REMOVAL..............................15
INSTALLATION...........................15
PEDAL
DESCRIPTION...........................16
OPERATION.............................16
REMOVAL..............................16
INSTALLATION...........................17
POWER BRAKE BOOSTER
DIAGNOSIS AND TESTING.................17
HYDRAULIC BOOSTER..................17
STANDARD PROCEDURE..................19
POWER BRAKE BOOSTER...............19
REMOVAL..............................19INSTALLATION...........................20
ROTORS
DIAGNOSIS AND TESTING.................20
DISC BRAKE ROTOR....................20
REMOVAL..............................21
INSTALLATION...........................22
BRAKE PADS/SHOES
REMOVAL..............................23
INSTALLATION...........................26
MASTER CYLINDER
DESCRIPTION...........................29
OPERATION.............................29
DIAGNOSIS AND TESTING.................29
MASTER CYLINDER/POWER BOOSTER.....29
STANDARD PROCEDURE..................30
MASTER CYLINDER BLEEDING...........30
REMOVAL..............................30
INSTALLATION...........................30
WHEEL CYLINDERS
REMOVAL..............................31
DISASSEMBLY...........................31
CLEANING..............................31
INSPECTION............................31
ASSEMBLY.............................31
INSTALLATION...........................32
SUPPORT PLATE
REMOVAL..............................32
INSTALLATION...........................32
DRUM
DESCRIPTION...........................32
OPERATION.............................32
DIAGNOSIS AND TESTING.................33
BRAKE DRUM.........................33
STANDARD PROCEDURE..................33
BRAKE DRUM MACHINING...............33
CLEANING..............................33
INSPECTION............................33
ADJUSTMENTS..........................34
PARKING BRAKE
DESCRIPTION...........................35
OPERATION.............................36
PEDAL
REMOVAL..............................36
INSTALLATION...........................36
CABLES
REMOVAL..............................37
INSTALLATION...........................38
CABLE TENSIONER
ADJUSTMENTS..........................40
BR/BEBRAKES 5 - 1

RELEASE
REMOVAL..............................40
INSTALLATION...........................41SHOES
REMOVAL..............................41
INSTALLATION...........................42
BRAKES - BASE
SPECIFICATIONS
BASE BRAKE
SPECIFICATIONS
DESCRIPTION SPECIFICATION
Front/Rear Disc Brake
Caliper
TypeDual Piston Sliding
Front Disc Brake Caliper
Piston Diameter LD54 mm (2.00 in.)
Front Disc Brake Caliper
Piston Diameter HD56 mm (2.00 in.)
Front Disc Brake Rotor
1500 4x2304ý30 mm (11.96ý1.18
in.)
Front Disc Brake Rotor
1500 4x4307.5ý30 mm
(12.10ý1.18 in.)
Front Disc Brake Rotor
2500/3500326.5ý36 mm (12.5ý1.5
in.)
Front/Rear Disc Brake
Rotor
Max. Runout0.127 mm (0.005 in.)
Front/Rear Disc Brake
Rotor
Max. Thickness Variation0.025 mm (0.001 in.)
Mininium Front Rotor
Thickness
150028.39 mm (1.117 in.)
Minimum Front Rotor
Thickness
2500/350033.90 mm (1.334 in.)
Mininium Rear Rotor
Thickness
2500/350028.39 mm (1.117 in.)
DESCRIPTION SPECIFICATION
Drum Brake
Size
1500279ý57 mm (11ý2.25 in.)
Drum Brake
Size
2500/3500308ý89 mm (12.125ý3.5
in.)
Drum Brake
Max. Runout
15000.18 mm (0.007 in.)
Drum Brake
Max. Thickness Variation
15000.076 mm (0.003 in.)
Rear Disc Brake Caliper
25002x45 mm (1.77 in)
Rear Disc Brake Caliper
35002x51 mm (2.00 in)
Rear Disc Brake Rotor
2500/3500323.5x30 mm (1.18 in)
Wheel Cylinder Bore Size
150025.4 mm (1.00 in.)
Wheel Cylinder Bore Size
2500/350025.4 mm (1.00 in.)
Brake Booster
Type
1500/2500 Gasoline
EnginesVacuum Dual Diaphragm
Brake Booster
Type
All 3500/
2500 Diesel Engines
OnlyHydraulic
5 - 2 BRAKESBR/BE

TORQUE CHART
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Booster
Mounting Nuts28 21 250
Booster
Mounting Nuts to the
Dashpanel33 24 300
Diesel Hydraulic Booster
Mounting Bolts28 21 250
Diesel Hydraulic Booster
Booster Lines28 21 250
Diesel Hydraulic Booster
Booster Hoses31 23 275
Master Cylinder
Mounting Nuts23 17 200
Master Cylinder
Brake Lines21 16 190
Combination Valve
Mounting Bolt23 17 210
Combination Valve
Brake Lines21 16 190
Proportioning Valve
Mounting Nuts34 25 300
Proportioning Valve
Brake Hose31 23 276
Proportioning Valve
Brake Lines21 16 190
Front Caliper
Mounting Bolts33 24 Ð
Front Caliper
LD Adapter Bolts176 130 Ð
Front Caliper
HD Adapter Bolts285 210 Ð
Rear Caliper
Slide Pins33 24 300
Rotor to Hub Rear
Bolt128 95 Ð
All Caliper
Banjo Bolts40 30 360
Wheel Cylinder
Mounting Bolts20 15 180
Wheel Cylinder
Brake Line13 10 115
Support Plate
Mounting Bolts58 43 Ð
BR/BEBRAKES 5 - 3
BRAKES - BASE (Continued)

DESCRIPTION N´m Ft. Lbs. In. Lbs.
Park Brake Pedal
Assembly
Mounting Bolts/Nuts28 21 250
Hub/Bearing
LD 4x2 Spindle Nut251 185 Ð
Hub/Bearing
HD 4x2 Spindle Nut380 280 Ð
Hub/Bearing
4x4 Hub/Bearing Bolts170 125 Ð
SPECIAL TOOLS
BASE BRAKES
HYDRAULIC/MECHANICAL
DESCRIPTION
This vehicle is equipped with front disc brakes and
rear drum brakes also certain vehicles have four
wheel disc brakes. The front and rear disc brakes
consist of dual piston calipers and ventilated rotors.
The rear brakes are dual brake shoe, internal
expanding units with cast brake drums. The parking
brake mechanism is cable operated and connected to
the rear brake trailing shoes. Power brake assist is
standard equipment. A vacuum operated power brake
booster is used on gas engine vehicles. A hydraulic
booster is used on diesel engine vehicles.
Two antilock brake systems are used on this vehi-
cle. A rear wheel antilock (RWAL) brake system and
all-wheel antilock brake system (ABS). The RWAL
and ABS systems are designed to retard wheel
lockup while braking. Retarding wheel lockup is
accomplished by modulating fluid pressure to the
wheel brake units. Both systems are monitored by a
microprocessor which controls the operation of the
systems.
Installer, Brake Caliper Dust Boot C-4340
Installer, Brake Caliper Dust Boot C-3716-A
Handle C-4171
Cap, Master Cylinder Pressure Bleed 6921
5 - 4 BRAKESBR/BE
BRAKES - BASE (Continued)

WARNING
WARNING: DUST AND DIRT ACCUMULATING ON
BRAKE PARTS DURING NORMAL USE MAY CON-
TAIN ASBESTOS FIBERS FROM PRODUCTION OR
AFTERMARKET LININGS. BREATHING EXCESSIVE
CONCENTRATIONS OF ASBESTOS FIBERS CAN
CAUSE SERIOUS BODILY HARM. EXERCISE CARE
WHEN SERVICING BRAKE PARTS. DO NOT CLEAN
BRAKE PARTS WITH COMPRESSED AIR OR BY
DRY BRUSHING. USE A VACUUM CLEANER SPE-
CIFICALLY DESIGNED FOR THE REMOVAL OF
ASBESTOS FIBERS FROM BRAKE COMPONENTS.
IF A SUITABLE VACUUM CLEANER IS NOT AVAIL-
ABLE, CLEANING SHOULD BE DONE WITH A
WATER DAMPENED CLOTH. DO NOT SAND, OR
GRIND BRAKE LINING UNLESS EQUIPMENT USED
IS DESIGNED TO CONTAIN THE DUST RESIDUE.
DISPOSE OF ALL RESIDUE CONTAINING ASBES-
TOS FIBERS IN SEALED BAGS OR CONTAINERS
TO MINIMIZE EXPOSURE TO YOURSELF AND OTH-
ERS. FOLLOW PRACTICES PRESCRIBED BY THE
OCCUPATIONAL SAFETY AND HEALTH ADMINIS-
TRATION AND THE ENVIRONMENTAL PROTECTION
AGENCY FOR THE HANDLING, PROCESSING, AND
DISPOSITION OF DUST OR DEBRIS THAT MAY
CONTAIN ASBESTOS FIBERS.
CAUTION: Never use gasoline, kerosene, alcohol,
motor oil, transmission fluid, or any fluid containing
mineral oil to clean the system components. These
fluids damage rubber cups and seals. Use only
fresh brake fluid or Mopar brake cleaner to clean or
flush brake system components. These are the only
cleaning materials recommended. If system contam-
ination is suspected, check the fluid for dirt, discol-
oration, or separation into distinct layers. Also
check the reservoir cap seal for distortion. Drain
and flush the system with new brake fluid if con-
tamination is suspected.
CAUTION: Use Mopar brake fluid, or an equivalent
quality fluid meeting SAE/DOT standards J1703 and
DOT 3. Brake fluid must be clean and free of con-
taminants. Use fresh fluid from sealed containers
only to ensure proper antilock component opera-
tion.
CAUTION: Use Mopar multi-mileage or high temper-
ature grease to lubricate caliper slide surfaces,
drum brake pivot pins, and shoe contact points on
the backing plates. Use multi-mileage grease or GE
661 or Dow 111 silicone grease on caliper slide pins
to ensure proper operation.
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
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.
BR/BEBRAKES 5 - 5
HYDRAULIC/MECHANICAL (Continued)