STEADY STATE, HIGH SPEED, NO WHEEL SLIP
The roller cage positions the rollers on the input shaft
flats during low and high speed overrunning and during
initial BOC lockup. The roller cage is rotating at input
shaft (propeller shaft) speed at all times. At low speeds,
the friction shoes (Fig. 31) are pressed against the fric-
tion ground via the garter spring (Fig. 32), creating a
drag force on the roller cage. The drag force positions
the cage, which in turn positions the rollers to one side
of the flat. The direction of this drag force (position of
the roller) is dependent on the input (propeller shaft)
rotational direction. Since the rollers are always in con-
tact with the outer race, due to centrifugal forces, the
rollers want to follow the outer race due to drag. During
overrunning operation, the outer race is rotating faster
than the input; causing the rollers to want to traverse
the flat from one side to the other. During low speeds,
the brake shoes counteract this effect. To avoid exces-
sive wear, the ground shoes are designed to lift off from
the friction ground due to centrifugal forces at higher
rotational speeds.
To keep the rollers in the overrunning position and
avoid undesired9high speed lockup9, a high speed
latch (Fig. 33) positions the cage before the ground
shoes lift off. A further explanation of the high speed
effects follows as well. Utilizing only the friction
shoes approach means that at high speed the
required ground shoe drag torque would cause exces-
sive brake shoe wear or the roller will begin tomigrate to the opposite side of the flat due to the
drag force of the outer race. This would result in sys-
tem lock-up. (Fig. 34) shows the BOC as it crosses
the speed where the brake shoe force is overcome by
the roller drag on the outer race. Notice that the
roller is locking up on the opposite side of the flat
and the cage supplies no force on the rollers.
Fig. 31 Front View of BOC
1 - GARTER SPRING
2 - FRICTION BRAKE SHOES
3 - FRICTION GROUND CONNECTED TO GROUND TAB
4 - INPUT SHAFT
Fig. 32 Location of the Grounding Element
1 - DIFFERENTIAL HOUSING
2 - GROUND TAB
3 - GARTER SPRING
Fig. 33 BOC High Speed Latch (Not Engaged)
1 - TOOTH (TWO PLACES)
2 - GARTER SPRING
3 - TABS AT BOTH ENDS FIT INTO SLOTS IN CAGE
4 - TWO PART DESIGN
RSREAR DRIVELINE MODULE3-39
BI-DIRECTIONAL OVERRUNNING CLUTCH (Continued)
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Fig. 46 Bi-directional Overrunning Clutch (BOC) and Viscous Coupler Powerflow
1 - POWERFLOW - BOC OVERUNNING 6 - VISCOUS COUPLER
2 - POWERFLOW - BOC LOCKED 7 - BOC ROLLER CAGE
3 - BOC GROUND TAB 8 - BOC INPUT SHAFT
4 - FRICTION BRAKE SHOES 9 - INPUT FLANGE
5 - BOC ROLLERS
RSREAR DRIVELINE MODULE3-45
VISCOUS COUPLER (Continued)
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BRAKES
TABLE OF CONTENTS
page page
BRAKES - BASE........................... 1BRAKES - ABS........................... 85
BRAKES - BASE
TABLE OF CONTENTS
page page
BRAKES - BASE
DESCRIPTION
DESCRIPTION - BASE BRAKES...........3
DESCRIPTION - BASE BRAKES (EXPORT) . . . 3
OPERATION - BASE BRAKES..............3
WARNING.............................4
CAUTION..............................4
DIAGNOSIS AND TESTING - BASE BRAKE
SYSTEM.............................4
STANDARD PROCEDURE - BASE BRAKE
BLEEDING............................7
SPECIFICATIONS
BRAKE FASTENER TORQUE.............9
SPECIAL TOOLS
BASE BRAKE SYSTEM..................9
BRAKE FLUID LEVEL SWITCH
DESCRIPTION.........................10
OPERATION...........................10
REMOVAL.............................10
INSTALLATION.........................10
ADJUSTABLE PEDAL SWITCH
DESCRIPTION.........................11
DIAGNOSIS AND TESTING - ADJUSTABLE
PEDAL SWITCH.......................11
REMOVAL.............................11
INSTALLATION.........................12
PEDAL POSITION SENSOR
DESCRIPTION.........................12
DIAGNOSIS AND TESTING - PEDAL
POSITION SENSOR....................13
REMOVAL.............................13
INSTALLATION.........................13
HYDRAULIC/MECHANICAL
DESCRIPTION
DESCRIPTION - DISC BRAKES (FRONT) . . . 14
DESCRIPTION - DISC BRAKES (REAR)....15
DESCRIPTION - DISC BRAKES (EXPORT) . . 15DESCRIPTION - DRUM BRAKES (REAR) . . . 16
OPERATION
OPERATION - DISC BRAKES (FRONT).....16
OPERATION - DISC BRAKES (REAR)......16
DIAGNOSIS AND TESTING - DRUM BRAKE
AUTOMATIC ADJUSTER................16
BRAKE LINES
DESCRIPTION - BRAKE TUBES AND HOSES . 17
OPERATION - BRAKE TUBES AND HOSES . . . 17
INSPECTION - BRAKE TUBES AND HOSES . . . 17
BRAKE PADS/SHOES - FRONT
REMOVAL
REMOVAL - FRONT DISC BRAKE SHOES
(DISC/DISC BRAKES)..................17
REMOVAL - FRONT DISC BRAKE SHOES
(DISC/DRUM BRAKES).................18
CLEANING - DISC BRAKE SHOES..........18
INSPECTION - DISC BRAKE SHOES........18
INSTALLATION
INSTALLATION - FRONT DISC BRAKE
SHOES.............................19
INSTALLATION - FRONT DISC BRAKE
SHOES (DISC/DRUM BRAKES)...........19
BRAKE PADS/SHOES - REAR DISC
REMOVAL - REAR DISC BRAKE SHOES.....19
CLEANING - DISC BRAKE SHOES..........21
INSPECTION - DISC BRAKE SHOES........21
INSTALLATION - REAR DISC BRAKE SHOES . . 21
BRAKE PADS/SHOES - REAR DRUM
REMOVAL - REAR DRUM BRAKE SHOES....22
INSPECTION - REAR DRUM BRAKE SHOE
LINING..............................25
INSTALLATION - REAR DRUM BRAKE SHOES . 25
ADJUSTMENTS
ADJUSTMENT - REAR DRUM BRAKE
SHOES.............................26
RSBRAKES5-1
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CONDITION POSSIBLE CAUSES CORRECTION
SCRAPING (METAL-TO-
METAL).1. Foreign object interference with
brakes.1. Inspect brakes and remove foreign
object.
2. Brake shoes worn out. 2. Replace brake shoes. Inspect rotors and
drums. Reface or replace as necessary.
OTHER BRAKE CONDITIONS
CONDITION POSSIBLE CAUSES CORRECTION
BRAKES CHATTER 1. Rear brake drum out of round or
disc brake rotor has excessive
thickness variation.1. Isolate condition as rear or front.
Reface or replace brake drums or
rotors as necessary.
BRAKES DRAG (FRONT
OR ALL)1. Contaminated brake fluid. 1. Check for swollen seals. Replace all
system components containing rubber.
2. Binding caliper pins or bushings. 2. Replace pins and bushings.
3. Binding master cylinder. 3. Replace master cylinder.
4. Binding brake pedal. 4. Replace brake pedal.
5. Brake lamp switch not adjusted
properly and mounting bracket is
bent.5. Straighten mounting bracket and
replace brake lamp switch.
BRAKES DRAG (REAR
ONLY)1. Parking brake cables binding or
froze up.1. Check cable routing. Replace cables
as necessary.
2. Parking brake cable return spring
not returning shoes.2. Replace cables as necessary.
3. Service brakes not adjusted
properly (rear drum brakes only).3. Follow the procedure listed in the
adjustment section.
4. Rear disc brake parking brake not
properly adjusted.Adjust parking brake shoes.
BRAKES GRAB 1. Contaminated brake shoe linings. 1. Inspect and clean, or replace shoes.
Repair source of contamination.
2. Improper power brake booster
assist.2. Refer to power brake booster
diagnosis and testing.
EXCESSIVE PEDAL
EFFORT1. Obstruction of brake pedal. 1. Inspect, remove or move obstruction.
2. Low power brake booster assist
(vacuum leak).2. Refer to power brake booster
diagnosis and testing.
3. Glazed brake linings. 3. Reface or replace brake rotors as
necessary. Replace brake shoes.
4. Brake shoe lining transfer to brake
rotor.4. Reface or replace brake rotors as
necessary. Replace brake shoes.
EXCESSIVE PEDAL
TRAVEL (VEHICLE STOPS
OK)1. Air in brake lines. 1. Bleed brakes.
2. Rear drum brake auto-adjuster
malfunctioning.2. Inspect and replace drum brake
components as necessary. Adjust rear
brakes.
5 - 6 BRAKES - BASERS
BRAKES - BASE (Continued)
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CONDITION POSSIBLE CAUSES CORRECTION
EXCESSIVE PEDAL
TRAVEL (ONE FRONT
WHEEL LOCKS UP
DURING HARD BRAKING)1. One of the two hydraulic circuits
to the front brakes is malfunctioning.1. Inspect system for leaks. Check
master cylinder for internal malfunction.
PEDAL PULSATES/
SURGES DURING
BRAKING1. Rear brake drum out of round or
disc brake rotor has excessive
thickness variation.1. Isolate condition as rear or front.
Reface or replace brake drums or
rotors as necessary.
PEDAL IS SPONGY 1. Air in brake lines. 1. Bleed brakes.
2. Power brake booster runout
(vacuum assist).2. Check booster vacuum hose and
engine tune for adequate vacuum
supply. Refer to power brake booster
diagnosis and testing.
PREMATURE REAR
WHEEL LOCKUP1. Contaminated brake shoe linings. 1. Inspect and clean, or replace shoes.
Repair source of contamination.
2. Inoperative proportioning valve
(non-ABS vehicles).2. Refer to proportioning valve
diagnosis and testing. Replace valve as
necessary.
3. Improper power brake booster
assist.3. Refer to power brake booster in the
diagnosis and testing section.
STOP/BRAKE LAMPS
S TAY O N1. Brake lamp switch out of
adjustment.1. Replace brake lamp switch.
2. Brake pedal binding. 2. Inspect and replace as necessary.
3. Obstruction in pedal linkage. 3. Remove obstruction.
4. Power Brake Booster not allowing
pedal to return completely.4. Replace power brake booster.
VEHICLE PULLS TO
RIGHT OR LEFT ON
BRAKING1. Frozen brake caliper piston. 1. Replace frozen piston or caliper.
Bleed brakes.
2. Contaminated brake shoe lining. 2. Inspect and clean, or replace shoes.
Repair source of contamination.
3. Pinched brake lines. 3. Replace pinched line.
4. Leaking piston seal. 4. Replace piston seal or brake caliper.
5. Suspension problem. 5. Refer to the Suspension group.
PARKING BRAKE -
EXCESSIVE HANDLE
TRAVEL1. Rear drum brakes or rear disc
brake parking brake shoes out of
adjustment.1. Adjust rear drum brake shoes, or
rear parking brake shoes on vehicles
with rear disc brakes.
STANDARD PROCEDURE - BASE BRAKE
BLEEDING
NOTE: This bleeding procedure is only for the vehi-
cle's base brakes hydraulic system. For bleeding
the antilock brakes hydraulic system, (Refer to 5 -
BRAKES - ABS - STANDARD PROCEDURE)CAUTION: Before removing the master cylinder
cover, thoroughly clean the cover and master cylin-
der fluid reservoir to prevent dirt and other foreign
matter from dropping into the master cylinder fluid
reservoir.
RSBRAKES - BASE5-7
BRAKES - BASE (Continued)
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NOTE: The following wheel sequence should be
used when bleeding the brake hydraulic system.
The use of this wheel sequence will ensure ade-
quate removal of all trapped air from the brake
hydraulic system.
²Left Rear Wheel
²Right Front Wheel
²Right Rear Wheel
²Left Front Wheel
NOTE: When bleeding the brake system, some air
may be trapped in the brake lines or valves far
upstream, as much as ten feet from the bleeder
screw (Fig. 2). Therefore, it is essential to have a
fast flow of a large volume of brake fluid when
bleeding the brakes to ensure all the air gets out.
The brakes may be manually bled or pressure bled.
Refer to the appropriate following procedure.
MANUAL BLEEDING PROCEDURE
NOTE: Correct manual bleeding of the brakes
hydraulic system will require the aid of a helper.
NOTE: To adequately bleed the brakes using the
manual bleeding procedure the rear brakes must be
correctly adjusted. Prior to the manual bleeding of
the brake hydraulic system, correctly adjust the
rear brakes.
(1) Pump the brake pedal three or four times and
hold it down before the bleeder screw is opened.
(2) Push the brake pedal toward the floor and hold
it down. Then open the left rear bleeder screw at
least 1 full turn. When the bleeder screw opens the
brake pedal will drop all the way to the floor.CAUTION: ªJust crackingº the bleeder screw often
restricts fluid flow, allowing only a slow, weak fluid
discharge of fluid. This practice will NOT get all the
air out. Make sure the bleeder is opened at least 1
full turn when bleeding.
(3) Release the brake pedal onlyafterthe bleeder
screw is closed.
(4) Repeat steps 1 through 3, four or five times, at
each bleeder screw in the proper sequence. This
should pass a sufficient amount of fluid to expel all
the trapped air from the brake system. Be sure to
monitor the fluid level in the master cylinder, so it
stays at a proper level so air will not enter the brake
system through the master cylinder.
(5) Check pedal travel. If pedal travel is excessive
or has not been improved, enough fluid has not
passed through the system to expel all the trapped
air. Continue to bleed system as necessary.
(6) Perform a final adjustment of the rear brake
shoes (when applicable), then test drive vehicle to be
sure brakes are operating correctly and that pedal is
solid.
PRESSURE BLEEDING PROCEDURE
CAUTION: Use bleeder tank Special Tool C-3496-B
or equivalent with Adapter, Special Tool 6921, to
pressurize the hydraulic system for bleeding.
Follow pressure bleeder manufacturer's instruc-
tions for use of pressure bleeding equipment.
(1) Install the Adapter Master Cylinder Pressure
Bleed Cap, Special Tool 6921 on the fluid reservoir of
the master cylinder (Fig. 3). Attach the fluid hose
from the pressure bleeder to the fitting on Special
Tool 6921.
(2) Attach a clear plastic hose to the bleeder screw
at one wheel and feed the hose into a clear jar con-
taining fresh brake fluid.
(3) Open the left rear wheel bleeder screw at least
one full turnor more to obtain an adequate flow of
brake fluid.
CAUTION: ªJust crackingº the bleeder screw often
restricts fluid flow, allowing only a slow, weak fluid
discharge of fluid. This practice will NOT get all the
air out. Make sure the bleeder is opened at least 1
full turn when bleeding.
(4) After 4 to 8 ounces of brake fluid has been bled
through the hydraulic system, and an air-free flow is
maintained in the hose and jar, this will indicate a
good bleed of the hydraulic system has been
obtained.
(5) Repeat the procedure at all the other remain-
ing bleeder screws.
Fig. 2 Trapped Air In Brake Fluid Line
1 - TRAPPED AIR
5 - 8 BRAKES - BASERS
BRAKES - BASE (Continued)
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BRAKE FLUID LEVEL SWITCH
DESCRIPTION
The brake fluid level switch is located in the brake
fluid reservoir of the master cylinder (Fig. 4).
OPERATION
The purpose of the brake fluid level switch is to
provide the driver with an early warning that the
brake fluid level in the master cylinder fluid reser-
voir has dropped below a normal level. This may
indicate:
²Abnormal loss of brake fluid in the master cyl-
inder fluid reservoir resulting from a leak in the
hydraulic system.
²Brake shoe linings which have worn to a point
requiring replacement.
As the brake fluid drops below the minimum level,
the brake fluid level switch closes to complete the red
BRAKE warning indicator (lamp) circuit. This will
turn on the red BRAKE warning indicator. The mas-
ter cylinder fluid reservoir should be checked and
refilled to the Full mark with DOT 3 brake fluid.If
the brake fluid level has dropped below the add
line in the master cylinder fluid reservoir, the
entire brake hydraulic system should be
checked for evidence of a leak.
REMOVAL
(1) Remove wiring harness connector from brake
fluid reservoir level switch (Fig. 4).
(2) Using fingers, compress the retaining tabs on
the opposite end of brake fluid level switch.
(3) With retaining tabs compressed, grasp the con-
nector end of brake fluid level switch and pull it out
of master cylinder brake fluid reservoir.
INSTALLATION
(1) Insert brake fluid level switch into left side of
brake fluid reservoir. Be sure switch is pushed in
until retaining tabs lock it to brake fluid reservoir.
(2) Connect vehicle wiring harness connector to
brake fluid level switch (Fig. 4).
Tubes, Master Cylinder Bleed 8358
Adapter, Master Cylinder Pressure Bleed Cap 6921
Dial Indicator, C-3339
Gauge, Brake Safe-Set
Handle, Universal C±4171
Installer, Dust Boot C-4689 or C-4842
5 - 10 BRAKES - BASERS
BRAKES - BASE (Continued)
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BRAKE LINES
DESCRIPTION - BRAKE TUBES AND HOSES
The brake tubes are steel with a corrosion-resis-
tant nylon coating applied to the external surfaces.
The flex hoses are made of reinforced rubber with fit-
tings at each end.
The primary and secondary brake tubes leading
from the master cylinder to the ABS ICU Hydraulic
Control Unit (HCU) or the non-ABS junction block
have a special flexible section. This flexible section is
required due to cradle movement while the vehicle is
in motion (The ICU and non-ABS junction block are
mounted to the cradle).If replacement of these
lines is necessary, only the original factory
brake line containing the flexible section must
be used.
OPERATION - BRAKE TUBES AND HOSES
The purpose of the chassis brake tubes and flex
hoses is to transfer the pressurized brake fluid devel-
oped by the master cylinder to the wheel brakes of
the vehicle. The flex hoses are made of rubber to
allow for the movement of the vehicle's suspension.
INSPECTION - BRAKE TUBES AND HOSES
Flexible rubber hose is used at both front brakes
and at the rear axle. Inspection of brake hoses
should be performed whenever the brake system is
serviced and every 7,500 miles or 12 months, which-
ever comes first (every engine oil change). Inspect
hydraulic brake hoses for surface cracking, scuffing,
or worn spots. If the fabric casing of the rubber hose
becomes exposed due to cracks or abrasions in the
rubber hose cover, the hose should be replaced imme-
diately. Eventual deterioration of the hose can take
place with possible burst failure. Faulty installation
can cause twisting, resulting in wheel, tire, or chassis
interference.
The brake tubing should be inspected periodically
for evidence of physical damage or contact with mov-
ing or hot components.
The flexible brake tube sections used on this vehi-
cle in the primary and secondary tubes from the
master cylinder to the ABS hydraulic control unit
connections must also be inspected. This flexible tub-
ing must be inspected for kinks, fraying and contact
with other components or with the body of the vehi-
cle.
BRAKE PADS/SHOES - FRONT
REMOVAL
REMOVAL - FRONT DISC BRAKE SHOES
(DISC/DISC BRAKES)
(1) Raise the vehicle. (Refer to LUBRICATION &
MAINTENANCE/HOISTING - STANDARD PROCE-
DURE).
(2) Remove both front wheel and tire assemblies.
(3) Begin on one side of the vehicle.
(4) Remove the anti-rattle clip from the outboard
side of the caliper and adapter.
(5) Remove the two caliper guide pin bolts.
(6) Remove caliper from caliper adapter and brake
rotor.
CAUTION: Supporting weight of caliper by the flex-
ible brake fluid hose can damage the hose.
(7) Using wire or cord, hang the caliper from the
front strut assembly (Fig. 20). Support the caliper
firmly to prevent weight of caliper from being sup-
ported by the brake fluid hose.
(8) Remove the outboard brake shoe from the cali-
per adapter.
(9) Pull the inboard brake shoe away from the cal-
iper piston until the retaining clip on shoe is free
from the cavity in the caliper piston (Fig. 21).
(10) Repeat the above procedure on other side of
the vehicle.
Fig. 20 Stored Front Disc Brake Caliper
1 - STEERING KNUCKLE
2 - BRAKE FLEX HOSE
3 - CALIPER ASSEMBLY
4 - WIRE HANGER
5 - STRUT ASSEMBLY
RSBRAKES - BASE5-17
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