wheel CHRYSLER VOYAGER 2004 Service Manual

ABS TRACTION CONTROL HYDRAULIC CIRCUIT,
SOLENOID VALVE, AND SHUTTLE VALVE
FUNCTION (ABS WITH TRACTION CONTROL)
The hydraulic diagram (Fig. 11) shows the vehicle
in the ABS braking mode. The diagram shows a drive
wheel is spinning and brake pressure is required to
reduce its speed.²The normally open ASR valve is energized to iso-
late the brake fluid being pumped from the master
cylinder and to isolate the driven wheel.
²The normally open ASR valve bypasses the
pump output back to the master cylinder at a fixed
pressure setting.
²The normally open and normally closed valves
modulate (build/decay) the brake pressure as
required to the spinning wheel.
Fig. 11 Traction Control Hydraulic Circuit
1 - OUTLET VALVE
2 - PUMP PISTON
3 - PUMP MOTOR (ON)
4 - LOW PRESSURE ACCUMULATOR PRESSURE
5 - LOW PRESSURE ACCUMULATOR
6 - NORMALLY CLOSED VALVE (MODULATING)
7 - TO RIGHT FRONT WHEEL (SPINNING)
8 - NORMALLY OPEN VALVE (MODULATING)
9 - NORMALLY OPEN ASR VALVE ON (REGULATING)10 - FROM MASTER CYLINDER
11 - HYDRAULIC SHUTTLE VALVE
12 - CONTROLLED WHEEL PRESSURE
13 - SUCTION VALVE
14 - PUMP INTERSTAGE PRESSURE
15 - NOISE DAMPER CHAMBER
16 - MASTER CYLINDER PRESSURE
17 - PUMP PRESSURE
5 - 88 BRAKES - ABSRS
HYDRAULIC/MECHANICAL (Continued)

HCU (HYDRAULIC CONTROL
UNIT)
DESCRIPTION
The hydraulic control unit (HCU) is mounted to
the CAB as part of the ICU (Fig. 22). The HCU con-
trols the flow of brake fluid to the brakes using a
series of valves and accumulators. A pump/motor is
mounted on the HCU to supply build pressure to the
brakes during an ABS stop.
The HCU on a vehicle equipped with ABS and
traction control has a valve block housing that is
approximately 1 inch longer on the low pressure fluid
accumulators side than a HCU on a vehicle that is
equipped with only ABS.
For more information, (Refer to 5 - BRAKES/HY-
DRAULIC/MECHANICAL/ICU (INTEGRATED CON-
TROL UNIT) - DESCRIPTION)
OPERATION
For information on the operation of the HCU as a
whole, refer to Hydraulic Circuits And Valve Opera-
tion which can be found elsewhere in this section.
For information on the operation of the components
within the HCU, refer to the following three topics.
VALVES AND SOLENOIDS
The valve block contains four inlet valves and four
outlet valves. The inlet valves are spring-loaded in
the open position and the outlet valves are spring-
loaded in the closed position during normal braking.
The fluid is allowed to flow from the master cylinder
to the wheel brakes.
During an ABS stop, these valves cycle to maintain
the proper slip ratio for each wheel. The inlet valve
closes preventing further pressure increase and the
outlet valve opens to provide a path from the wheel
brake to the HCU accumulators and pump/motor.
This releases (decays) pressure from the wheel brake,
thus releasing the wheel from excessive slippage.
Once the wheel is no longer slipping, the outlet valve
is closed and the inlet valve is opened to reapply
(build) pressure.
On vehicles with traction control, there is an extra
set of valves and solenoids. The ASR valves, mounted
in the HCU valve block, are normally in the open
position and close only when the traction control is
applied.
These isolator valves are used to isolate the rear
(non-driving) wheels of the vehicle from the hydraulic
pressure that the HCU pump/motor is sending to the
front (driving) wheels when traction control is being
applied. The rear brakes need to be isolated from the
master cylinder when traction control is being
applied so the rear wheels do not drag. For moreinformation, refer to Traction Control System in this
section.
BRAKE FLUID ACCUMULATORS
There are two fluid accumulators in the HCU±one
for the primary hydraulic circuit and one for the sec-
ondary hydraulic circuit. Each hydraulic circuit uses
a 5 cc accumulator.
The fluid accumulators temporarily store brake
fluid that is removed from the wheel brakes during
an ABS cycle. This stored fluid is used by the pump/
motor to provide build pressure for the brake hydrau-
lic system. When the antilock stop is complete, the
accumulators are drained by the pump/motor.
On ABS-only vehicles, there is a mini-accumulator
on the secondary hydraulic circuit that protects the
master cylinder seals during an ABS stop, and there
is a noise dampening chamber on the primary circuit.
On ABS with traction control vehicles, there are
two noise dampening chambers in the HCU.
PUMP/MOTOR
There are two pump assemblies in the HCUÐone
for the primary hydraulic circuit and one for the sec-
ondary hydraulic circuit. Both pumps are driven by a
common electric motor. This DC-type motor is inte-
gral to the HCU and is controlled by the CAB.
The pump/motor provides the extra amount of
brake fluid needed during antilock braking. Brake
fluid is released to the accumulators when the outlet
valve is opened during an antilock stop. The pump
mechanism consists of two opposing pistons operated
by an eccentric camshaft. In operation, one piston
draws fluid from the accumulators, and the opposing
piston pumps fluid to the master cylinder circuits.
When the antilock stop is complete, the pump/motor
drains the accumulators.
The CAB may turn on the pump/motor when an
antilock stop is detected. The pump/motor continues
to run during the antilock stop and is turned off after
the stop is complete. Under some conditions, the
pump/motor runs to drain the accumulators during
the next drive-off.
The pump/motor is not a serviceable item; if it
requires replacement, the HCU must be replaced.
ICU (INTEGRATED CONTROL
UNIT)
DESCRIPTION
The hydraulic control unit (HCU) and the control-
ler antilock brake (CAB) used with this antilock
brake system are combined (integrated) into one
unit, which is called the integrated control unit (ICU)
RSBRAKES - ABS5-89

(10) Disconnect the 24±way connector from the
CAB. To disconnect the 24±way connector, grasp the
lock on the 24±way connector and pull it as far up as
possible. This will unlock the 24±way connector from
the socket on the CAB.
CAUTION: Before removing the brake tubes from
the HCU, the HCU must be thoroughly cleaned. This
must be done to prevent dirt particles from falling
into the ports of HCU or entering the brake tubes.
(11) Thoroughly clean all surfaces of the ICU and
brake tube nuts. Use only a solvent such as Mopart
Brake Parts Cleaner or equivalent to clean the ICU.
(12) Remove the brake tubes (4) from the outlet
ports on the HCU (Fig. 14).
(13) Remove the primary and secondary brake
tubes from the inlet ports on the HCU (Fig. 14).
(14) Center and prop the steering wheel.
(15) Remove the pinch bolt and disconnect the
steering shaft coupling.
(16) If equipped, remove the two clips securing
silencer to dash seal (Fig. 15). Remove silencer.
(17) Remove the three screws securing the dash
seal (Fig. 15). Remove seal.
(18) Remove the 3 bolts attaching the ICU to its
mounting bracket (Fig. 16).
(19) Remove ICU from the vehicle through engine
compartment.
(20) If required, to separating the CAB from the
HCU, (Refer to 5 - BRAKES - ABS/HYDRAULIC/ME-
CHANICAL/ICU (INTEGRATED CONTROL UNIT) -
DISASSEMBLY).
REMOVAL - RHD
NOTE: Before proceeding, (Refer to 5 - BRAKES -
WARNING)(Refer to 5 - BRAKES - CAUTION)
(1) Disconnect the negative (ground) cable from
the battery and isolate cable.
Fig. 14 Brake Tube Nuts At ICU
1 - PRIMARY BRAKE TUBE
2 - SECONDARY BRAKE TUBE
3 - CHASSIS BRAKE TUBES
Fig. 15 Lower Coupling And Dash Seal
1 - COUPLING
2 - DASH SEAL
3 - SILENCER
4 - MOUNTING SCREWS
5 - RETAINING CLIPS
6 - DASH
Fig. 16 ICU Mounting Bolts
1 - ICU MOUNTING BOLTS
2 - COUPLER
RSBRAKES - ABS5-91
ICU (INTEGRATED CONTROL UNIT) (Continued)

(2) Using a brake pedal depressor, move and lock
the brake pedal to a position past the first inch of
pedal travel.This will prevent brake fluid from
draining out of the master cylinder when the
brake tubes are removed from the HCU.
(3) Raise vehicle. (Refer to LUBRICATION &
MAINTENANCE/HOISTING - STANDARD PROCE-
DURE)
(4) Remove the routing clip attaching the ICU wir-
ing harness to the ICU mounting bracket (Fig. 17).
CAUTION: Do not apply a 12 volt power source to
any terminals of the HCU connector when discon-
nected.
(5) Remove the 24-way connector (Fig. 17) from
the CAB. The 24-way connector is removed from the
CAB using the following procedure. Grasp the lock
on the 24-way connector (Fig. 17) and pull it as far
out as possible (Fig. 18). This will raise and unlock
the 24-way connector from the socket on the CAB.
CAUTION: Before removing the brake tubes from
the HCU, the HCU must be thoroughly cleaned. This
must be done to prevent dirt particles from falling
into the ports of HCU or entering the brake tubes.(6) Thoroughly clean all surfaces of the HCU, and
all brake tube nuts located on the HCU. Use only a
solvent such as Mopar Brake Parts Cleaner or an
equivalent to clean the HCU.
(7) Remove the brake tubes (6) from the inlet and
outlet ports on the HCU. (Fig. 19).
Fig. 17 CAB 24-Way Connector
1 - CAB WIRING HARNESS
2 - 24±WAY CONNECTOR
3 - FLOOR PAN
4 - HCU
5 - CAB
6 - HCU MOUNTING BRACKET
7 - CONNECTOR LOCK
Fig. 18 Unlocked 24-Way CAB Connector
1 - HCU
2 - CAB
3 - 24±WAY CONNECTOR
4 - CONNECTOR LOCK (UNLOCKED)
Fig. 19 Brake Tube Connections To HCU
1 - LEFT REAR WHEEL BRAKE TUBE
2 - SECONDARY BRAKE TUBE FROM MASTER CYLINDER
3 - LEFT FRONT WHEEL BRAKE TUBE
4 - CAB
5 - RIGHT REAR WHEEL BRAKE TUBE
6 - HCU MOUNTING BRACKET
7 - BRAKE TUBE TO HCU CONNECTION LOCATION LEGEND
8 - RIGHT FRONT WHEEL BRAKE TUBE
9 - PRIMARY BRAKE TUBE FROM MASTER CYLINDER
5 - 92 BRAKES - ABSRS
ICU (INTEGRATED CONTROL UNIT) (Continued)

ASSEMBLY - ICU
(1) Install the CAB (Fig. 24) on the HCU.
(2) Install the 4 bolts mounting the CAB (Fig. 23)
to the HCU. Tighten the CAB mounting bolts to a
torque of 2 N´m (17 in. lbs.).
(3) Plug the pump/motor wiring harness into the
CAB.
(4) Install the ICU in the vehicle and bleed the
base and ABS hydraulic systems. (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/ICU (INTE-
GRATED CONTROL UNIT) - INSTALLATION)
INSTALLATION
INSTALLATION - LHD
(1) Place the ICU in its bracket below the master
cylinder. Start the upper mounting bolt to hold it in
place.
(2) Inside the vehicle, install the remaining 2
mounting bolts attaching the ICU to the mounting
bracket (Fig. 16). Tighten all 3 mounting bolts to a
torque of 11 N´m (97 in. lbs.).
(3) Install the dash seal and three mounting
screws (Fig. 15).
(4) If equipped, install the silencer on top of the
dash seal (Fig. 15).
(5) Connect the steering shaft coupling and install
the pinch bolt (Fig. 15). Tighten the pinch bolt to 28
N´m (250 in. lbs.).
(6) Remove the steering wheel holder.
CAUTION: Because of the flexible section in the pri-
mary and secondary brake tubes, the brake tubes
must be held in proper orientation when tightened
and torqued. These tubes must not contact eachother or other vehicle components when installed.
Also, after the brake tubes are installed on the HCU,
ensure all spacer clips are reinstalled on the brake
tubes.
(7) Install the primary and secondary brake tubes
into their correct port locations on the HCU valve
block (Fig. 14). Tighten the tube nuts to a torque of
17 N´m (145 in. lbs.).
CAUTION: When installing the chassis brake tubes
on the HCU valve block, they must be located cor-
rectly in the valve block to ensure proper ABS oper-
ation.
NOTE: The chassis brake tube attachment locations
to the HCU, are marked on the bottom of the CAB.
(8) Install the (4) chassis brake tubes into their
correct port locations on the HCU valve block as
shown (Fig. 14). Tighten the tube nuts to a torque of
17 N´m (145 in. lbs.).
NOTE: Before installing the 24±way connector in
the CAB be sure the seal is properly installed in the
connector.
(9) Install the 24±way connector on the CAB by,
first, positioning the 24±way connector in the socket
of the CAB and carefully pushing it down as far as
possible. Once connector is fully seated by hand into
the CAB socket, push down on connector lock. This
will pull the connector into the socket of the CAB
and lock it in the installed position.
(10) Install any routing clips on the brake tubes.
(11) Remove the brake pedal holder.
(12) Install the speed control servo with its mount-
ing nuts.
(13) Connect the wiring harness to the speed con-
trol servo.
(14) Install the battery tray (Refer to 8 - ELEC-
TRICAL/BATTERY SYSTEM/TRAY - INSTALLA-
TION).
(15) Install the screw securing the coolant filler
neck to the battery tray.
(16) Reconnect the vacuum hose connector at the
tank built into the battery tray.
(17) Install the battery (Refer to 8 - ELECTRI-
CAL/BATTERY SYSTEM/BATTERY - INSTALLA-
TION).
(18) Install the battery shield.
(19) Remove the brake pedal holder.
(20) Connect negative cable back on negative post
of the battery.
(21) Bleed the Base and ABS brake hydraulic sys-
tems (Refer to 5 - BRAKES - STANDARD PROCE-
DURE).
Fig. 24 (TYPICAL) Remove/Install CAB
1 - CAB
2 - HCU VALVES
3 - HCU VALVE BLOCK
5 - 94 BRAKES - ABSRS
ICU (INTEGRATED CONTROL UNIT) (Continued)

DISC BRAKE CALIPER ADAPTERREMOVAL - FRONT DISC BRAKE CALIPERADAPTER ...........................30
INSTALLATION - FRONT DISC BRAKE CALIPER ADAPTER ....................30
DISC BRAKE CALIPER GUIDE PINS REMOVAL - DISC BRAKE CALIPER GUIDEPINS (TRW BRAKES) ..................30
INSTALLATION - DISC BRAKE CALIPER GUIDE PINS (TRW BRAKES) .............30
DRUM REMOVAL .............................31
INSTALLATION .........................31
FLUID DIAGNOSIS AND TESTING - BRAKE FLUIDCONTAMINATION .....................31
STANDARD PROCEDURE - BRAKE FLUID LEVEL CHECKING .....................31
SPECIFICATIONS BRAKE FLUID ........................32
JUNCTION BLOCK DESCRIPTION - NON-ABS JUNCTION BLOCK . 32
OPERATION - NON-ABS JUNCTION BLOCK . . 32
REMOVAL - NON-ABS JUNCTION BLOCK ....32
INSTALLATION - NON-ABS JUNCTION BLOCK . 32
MASTER CYLINDER DESCRIPTION DESCRIPTION ........................33
DESCRIPTION - RHD ..................34
OPERATION ...........................34
STANDARD PROCEDURE - MASTER CYLINDER BLEEDING ..................34
REMOVAL REMOVAL - LHD ......................35
REMOVAL - RHD ......................36
DISASSEMBLY - MASTER CYLINDER (FLUID RESERVOIR) .........................36
ASSEMBLY - MASTER CYLINDER (FLUID RESERVOIR) .........................37
INSTALLATION INSTALLATION - LHD ..................37
INSTALLATION - RHD ..................38
PEDALS - ADJUSTABLE REMOVAL .............................38
INSTALLATION .........................40
PEDAL TORQUE SHAFT - RHD REMOVAL .............................42
INSTALLATION .........................43
POWER BRAKE BOOSTER DESCRIPTION .........................43
OPERATION ...........................44
DIAGNOSIS AND TESTING - POWER BRAKE BOOSTER ...........................44
REMOVAL REMOVAL - LHD ......................45
REMOVAL - RHD ......................47 INSTALLATION
INSTALLATION - LHD ..................49
INSTALLATION - RHD ..................50
PROPORTIONING VALVE DESCRIPTION - PROPORTIONING VALVE(HEIGHT SENSING) ....................51
OPERATION - PROPORTIONING VALVE (HEIGHT SENSING) ....................51
DIAGNOSIS AND TESTING - PROPORTIONING VALVE (HEIGHT
SENSING) ...........................52
REMOVAL - PROPORTIONING VALVE (HEIGHT SENSING) ....................53
INSTALLATION - PROPORTIONING VALVE (HEIGHT SENSING) ....................53
ROTOR DIAGNOSIS AND TESTING - BRAKE ROTOR . . 54
STANDARD PROCEDURE - BRAKE ROTORMACHINING ..........................56
REMOVAL - FRONT BRAKE ROTOR ........57
INSTALLATION - FRONT BRAKE ROTOR .....57
SPECIFICATIONS BRAKE ROTOR .......................57
BRAKE ROTOR - EXPORT ..............58
SUPPORT PLATE - DRUM BRAKE REMOVAL .............................58
INSTALLATION .........................58
WHEEL CYLINDERS REMOVAL .............................59
INSPECTION ..........................59
INSTALLATION .........................60
PARKING BRAKE DESCRIPTION DESCRIPTION ........................60
DESCRIPTION - EXPORT ...............60
OPERATION ...........................60
STANDARD PROCEDURE STANDARD PROCEDURE - PARKINGBRAKE AUTOMATIC ADJUSTER TENSION
RELEASE ...........................61
STANDARD PROCEDURE - PARKING BRAKE AUTOMATIC ADJUSTER TENSION
RESET .............................61
CABLES - PARKING BRAKE REMOVAL REMOVAL - PARKING BRAKE CABLE(FRONT) ............................62
REMOVAL - PARKING BRAKE CABLE (INTERMEDIATE) ......................62
REMOVAL - PARKING BRAKE CABLE (RIGHT REAR) ........................63
REMOVAL - PARKING BRAKE CABLE (LEFT REAR )..............................64
INSTALLATION INSTALLATION - PARKING BRAKE CABLE(FRONT) ............................65
5s - 2 BRAKESRS

INSTALLATION - PARKING BRAKE CABLE(INTERMEDIATE) ......................66
INSTALLATION - PARKING BRAKE CABLE (RIGHT REAR) ........................66
INSTALLATION - PARKING BRAKE CABLE (LEFT REAR) .........................66
ADJUSTMENTS ADJUSTMENT - PARKING BRAKE CABLES . 66
CABLES - PARKING BRAKE (EXPORT) REMOVAL - FRONT CABLE ...............67
INSTALLATION - FRONT CABLE ............67
LEVER - PARKING BRAKE REMOVAL .............................67 INSTALLATION
.........................67
LEVER - PARKING BRAKE (EXPORT) REMOVAL - PARKING BRAKE LEVER ANDFRONT CABLE .......................68
INSTALLATION - PARKING BRAKE LEVER AND FRONT CABLE ...................69
SHOES - PARKING BRAKE REMOVAL .............................69
INSTALLATION .........................75
ADJUSTMENTS ADJUSTMENT - PARKING BRAKE SHOES . . 76
BRAKES - BASE
DESCRIPTION
DESCRIPTION - BASE BRAKES
The base brake system consists of the following
components: ² Brake pedal
² Power brake booster
² Master cylinder
² Brake tubes and hoses
² Proportioning valve (non-ABS vehicles only)
² Disc brakes
² Drum brakes
² Brake lamp switch
² Brake fluid level switch
² Parking brakes
Front disc brakes control the braking of the front
wheels; rear braking is controlled by rear drum
brakes or rear disc brakes depending on options. The hydraulic brake system is diagonally split on
both the non-antilock braking systems and antilock
braking systems. That means the left front and right
rear brakes are on one hydraulic circuit and the right
front and left rear are on the other. For information on the brake lamp switch, (Refer
to 8 - ELECTRICAL/LAMPS/LIGHTING - EXTERI-
OR/BRAKE LAMP SWITCH - DESCRIPTION) Vehicles equipped with the optional antilock brake
system (ABS) use a system designated Mark 20e. It
is available with or without traction control. This
system shares most base brake hardware used on
vehicles without ABS. ABS components are described
in detail in ANTILOCK BRAKE SYSTEM.
DESCRIPTION - BASE BRAKES (EXPORT)
Four-Wheel Disc Antilock Brakes are standard on
all models.
OPERATION - BASE BRAKES
When a vehicle needs to be stopped, the driver
applies the brake pedal. The brake pedal pushes the
input rod of the power brake booster into the booster.
The booster uses vacuum to ease pedal effort as force
is transferred through the booster to the master cyl-
inder. The booster's output rod pushes in the master
cylinder's primary and secondary pistons applying
hydraulic pressure through the chassis brake tubes
to the brakes at each tire and wheel assembly. The parking brakes are foot-operated. When
applied, the parking brake lever pulls on cables that
actuate brake shoes at each rear wheel. These shoes
come in contact with a hub mounted drum (drum for
disc/drum brakes or drum-in-hat for disc/disc brakes)
and hold it in place.
WARNING
WARNING: DUST AND DIRT ACCUMULATING ON
BRAKE PARTS DURING NORMAL USE MAY CON-
TAIN ASBESTOS FIBERS FROM PRODUCTION OR
AFTERMARKET BRAKE LININGS. BREATHING
EXCESSIVE CONCENTRATIONS OF ASBESTOS
FIBERS CAN CAUSE SERIOUS BODILY HARM.
EXERCISE CARE WHEN SERVICING BRAKE
PARTS. DO NOT SAND OR GRIND BRAKE LINING
UNLESS EQUIPMENT USED IS DESIGNED TO CON-
TAIN THE DUST RESIDUE. DO NOT CLEAN BRAKE
PARTS WITH COMPRESSED AIR OR BY DRY
BRUSHING. CLEANING SHOULD BE DONE BY
DAMPENING THE BRAKE COMPONENTS WITH A
FINE MIST OF WATER, THEN WIPING THE BRAKE
COMPONENTS CLEAN WITH A DAMPENED CLOTH.
DISPOSE OF CLOTH AND ALL RESIDUE CONTAIN-
ING ASBESTOS FIBERS IN AN IMPERMEABLE
CONTAINER WITH THE APPROPRIATE LABEL. FOL-
LOW PRACTICES PRESCRIBED BY THE OCCUPA-
TIONAL SAFETY AND HEALTH ADMINISTRATION
(OSHA) AND THE ENVIRONMENTAL PROTECTION
AGENCY (EPA) FOR THE HANDLING, PROCESSING,
AND DISPOSING OF DUST OR DEBRIS THAT MAY
CONTAIN ASBESTOS FIBERS.
RS BRAKES5s-3

CONDITION POSSIBLE CAUSES CORRECTION
DISC BRAKE SQUEAK AT
LOW SPEED (WHILE
APPLYING LIGHT BRAKE
PEDAL EFFORT) 1. Brake shoe linings. 1. Replace brake shoes.
DRUM BRAKE CHIRP 1. Lack of lubricant on brake shoe support plate where shoes ride. 1. Lubricate shoe contact areas on brake
shoe support plates.
DRUM BRAKE CLUNK 1. Drum(s) have threaded machined braking surface. 1. Replace brake drums as necessary.
DRUM BRAKE HOWL OR
MOAN 1. Lack of lubricant on brake shoe
support plate where shoes ride and
at the anchor. 1. Lubricate shoe contact areas on brake
shoe support plates and at the anchor.
2. Rear brake shoes. 2. Replace rear brake shoes.
DRUM BRAKE SCRAPING
OR WHIRRING 1. ABS wheel speed sensor or tone
wheel. 1. Inspect, correct or replace faulty
component(s).
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.
RS
BRAKES5s-5
BRAKES - BASE (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
EXCESSIVE PEDAL
EFFORT 1. 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.
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
BRAKING 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.
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 LOCKUP 1. 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 N 1. 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
BRAKING 1. 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.
5s - 6 BRAKESRS
BRAKES - BASE (Continued)

CONDITION POSSIBLE CAUSES CORRECTION4. Leaking piston seal. 4. Replace piston seal or brake caliper.
5. Suspension problem. 5. Refer to the Suspension group.
PARKING BRAKE -
EXCESSIVE HANDLE
TRAVEL 1. 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.
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.
² Left Rear Wheel
² Right Front Wheel
² Right Rear Wheel
² Left 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. 1). 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 only afterthe 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.
Fig. 1 Trapped Air In Brake Fluid Line
1 - TRAPPED AIR
RS BRAKES5s-7
BRAKES - BASE (Continued)