transmission fluid DODGE TOWN AND COUNTRY 2003 User Guide
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Page 104 of 2177

CAUTION: The steering knuckle to strut assembly
attaching bolts are serrated and must not be turned
during installation. Install nuts while holding bolts
stationary in the steering knuckle.
CAUTION: If the vehicle being serviced is equipped
with eccentric strut assembly attaching bolts, the
eccentric bolt must be installed in the bottom (slot-
ted) hole on the strut clevis bracket (Fig. 10).
(7) Install steering knuckle in clevis bracket of
strut damper assembly. Install the strut damper to
steering knuckle attaching bolts. Tighten both bolts
to a torque of 81 N´m (60 ft. lbs.) plus an additional
1/4 turn.
(8) Install braking disc on hub and bearing assem-
bly.
(9) Install disc brake caliper assembly on steering
knuckle. Caliper is installed by first sliding bottom of
caliper assembly under abutment on steering
knuckle, and then rotating top of caliper against top
abutment.
(10) Install disc brake caliper adapter to steering
knuckle attaching bolts (Fig. 4). Tighten the discbrake caliper adapter attaching bolts to a torque of
169 N´m (125 ft. lbs.).
(11) Clean all foreign matter from the threads of
the outer CV joint. Install the washer and half shaft
to hub/bearing assembly nut on half shaft and
securely tighten nut.
(12) Install front wheel and tire assembly. Install
and tighten the wheel mounting stud nuts in proper
sequence until all nuts are torqued to half the
required specification. Then repeat the tightening
sequence to the full specified torque of 135 N´m (100
ft. lbs.).
(13) Lower vehicle.
(14) With the vehicle's brakes applied to keep hub
from turning, tighten the hub nut to a torque of 244
N´m (180 ft. lbs.) (Fig. 11).
(15) Install the spring wave washer on the end of
the half shaft.
(16) Install the hub nut lock, and anewcotter pin
(Fig. 2). Wrap cotter pin prongs tightly around the
hub nut lock as shown in (Fig. 2).
(17) Check for correct fluid level in transaxle
assembly. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 41TE/FLUID - STANDARD
PROCEDURE)
Fig. 10 Correctly Installed Eccentric Attaching Bolt
1 - STEERING KNUCKLE
2 - FLANGED BOLT IN TOP HOLE
3 - CAM BOLT IN BOTTOM HOLE
4 - STRUT CLEVIS BRACKET
Fig. 11 Torquing Front Half Shaft To Hub Nut
1 - TORQUE WRENCH
RSHALF SHAFT - FRONT3-5
HALF SHAFT - FRONT (Continued)
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REAR DRIVELINE MODULE
TABLE OF CONTENTS
page page
REAR DRIVELINE MODULE
DESCRIPTION.........................23
OPERATION...........................23
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - REAR
DRIVELINE MODULE NOISE.............24
DIAGNOSIS AND TESTING - REAR
DRIVELINE MODULE OPERATION........26
REMOVAL.............................26
DISASSEMBLY.........................27
ASSEMBLY............................29
INSTALLATION.........................33
SPECIFICATIONS - REAR DRIVELINE
MODULE............................34
SPECIAL TOOLS.......................34
BI-DIRECTIONAL OVERRUNNING CLUTCH
DESCRIPTION.........................34
OPERATION...........................36
DIFFERENTIAL ASSEMBLY
DESCRIPTION.........................39OPERATION...........................39
FLUID - DIFFERENTIAL ASSEMBLY
STANDARD PROCEDURE - DIFFERENTIAL
ASSEMBLY FLUID CHANGE.............40
FLUID - OVERRUNNING CLUTCH HOUSING
STANDARD PROCEDURE - OVERRUNNING
CLUTCH HOUSING FLUID CHANGE.......41
VISCOUS COUPLER
DESCRIPTION.........................41
OPERATION...........................42
TORQUE ARM
REMOVAL.............................44
INSTALLATION.........................44
INPUT FLANGE SEAL
REMOVAL.............................44
INSTALLATION.........................45
OUTPUT FLANGE SEAL
REMOVAL.............................45
INSTALLATION.........................46
REAR DRIVELINE MODULE
DESCRIPTION
The rear driveline module assembly (Fig. 1) con-
sists of four main components:
²Bi-Directional Overrunning Clutch (BOC)
²Viscous Coupling
²Differential Assembly
²Torque Arm
The viscous coupling and bi-directional overrun-
ning clutch are contained within an overrunning
clutch housing, which fastens to the differential
assembly. The overrunning clutch housing and differ-
ential assembly have unique fluid sumps, each
requiring their own type and capacity of fluid. The
overrunning clutch housing requires MopartATF+4
(Automatic Transmission FluidÐType 9602) or equiv-
alent. The differential assembly requires Mopart
80W-90 Gear and Axle Lubricant.
Driveline module service is limited to the following
components:
²Differential Assembly (serviced only as assem-
bly)
²Viscous Coupling
²Bi-Directional Overrunning Clutch (BOC)
²Overrunning Clutch Housing²Seals (Input Flange, Output Flange, Overrun-
ning Clutch Housing O-rings)
²Input Flange/Shield
²Torque Arm
²Vents
²Fasteners
OPERATION
The primary benefits of All Wheel Drive are:
²Superior straight line acceleration, and corner-
ing on all surfaces
²Better traction and handling under adverse con-
ditions, resulting in improved hill climbing ability
and safer driving.
The heart of the system is an inter-axle viscous
coupling. The vehicle retains predominantly front-
wheel drive characteristics, but the All Wheel Drive
capability takes effect when the front wheels start to
slip. Under normal level road, straight line driving,
100% of the torque is allocated to the front wheels.
The viscous coupling controls and distributes torque/
power to the rear wheels. The viscous coupling trans-
mits torque to the rear wheels in proportion of the
amount of the slippage at the front wheels. Thais
variable torque distribution is automatic with no
driver inputs required. The coupling is similar to a
multi-plate clutch. It consists of a series of closely
spaced discs, which are alternately connected to the
RSREAR DRIVELINE MODULE3-23
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front and rear drive units. The unit is totally sealed
and partially filled with silicone fluid. There is no
adjustment, maintenance or fluid checks required
during the life of the unit.
The overrunning clutch allows the rear wheels to
overrun the front wheels during a rapid front wheel
lock braking maneuver. The overrunning action pre-
vents any feed-back of front wheel braking torque to
the rear wheels. It also allows the braking system to
control the braking behavior as a two wheel drive
(2WD) vehicle.
The overrunning clutch housing has a separate oil
sump and is filled independently from the differen-
tial. The fill plug is located on the side of the over-
running clutch case. When filling the overrunning
clutch with lubricant use MopartATF+4 (Automatic
Transmission FluidÐType 9602) or equivalent.
The differential assembly contains a conventional
open differential with hypoid ring gear and pinion
gear set. The hypoid gears are lubricated by SAE
80W-90 gear lubricant.DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - REAR DRIVELINE
MODULE NOISE
Different sources can be the cause of noise that the
rear driveline module assembly is suspected of mak-
ing. Refer to the following causes for noise diagnosis.
DRIVELINE MODULE ASSEMBLY NOISE
The most important part of driveline module ser-
vice is properly identifying the cause of failures and
noise complaints. The cause of most driveline module
failures is relatively easy to identify. The cause of
driveline module noise is more difficult to identify.
If vehicle noise becomes intolerable, an effort
should be made to isolate the noise. Many noises that
are reported as coming from the driveline module
may actually originate at other sources. For example:
²Tires
²Road surfaces
²Wheel bearings
Fig. 1 AWD Driveline Module Assembly
1 - TORQUE ARM 8 - WASHER 15 - PLUG-OVERRUNNING CLUTCH
HOUSING DRAIN
2 - INPUT FLANGE 9 - BI-DIRECTIONAL OVERRUNNING
CLUTCH (BOC)16 - SNAP RING
3 - FLANGE NUT 10 - VISCOUS COUPLER 17 - BEARING
4 - WASHER 11 - SHIM (SELECT) 18 - OVERRUNING CLUTCH HOUSING
5 - SHIELD 12 - O-RING 19 - SEAL-INPUT FLANGE
6 - VENT 13 - DIFFERENTIAL ASSEMBLY
7 - O-RING 14 - PLUG-DIFFERENTIAL FILL
3 - 24 REAR DRIVELINE MODULERS
REAR DRIVELINE MODULE (Continued)
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DIAGNOSIS AND TESTING - REAR DRIVELINE
MODULE OPERATION
Driveline module operation requires relatively
straight-forward diagnosis. Refer to the following
chart:
DRIVELINE MODULE DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
Rear wheels not
overrunning1) Bi-directional overrunning clutch
failure1) Replace overrunning clutch
components as required
No AWD in forward or
reverse directions, propeller
shaft turning1) Bi-directional overrunning clutch
failure1) Replace overrunning clutch
components as required
2) Viscous coupling failure 2) Replace viscous coupling
3) Rear differential failure 3) Replace the rear differential
assembly
No AWD in forward or
reverse directions, propeller
shaft not turning1) Power transfer unit failure. 1) Replace power transfer unit
components as necessary
Vibration at all speeds,
continuous torque transfer1) Mis-matched tires, worn tires on
front axle.1) Replace worn or incorrect
(mis-matched) tires with same
make and size
REMOVAL
(1) Raise vehicle on hoist.
(2) Drain fluid from overrunning clutch housing
and/or differential assembly if necessary.
(3) Remove propeller shaft. (Refer to 3 - DIFFER-
ENTIAL & DRIVELINE/PROPELLER SHAFT -
REMOVAL)
(4) Disconnect left and right rear halfshafts from
output flanges (Fig. 2).
(5) Remove torque arm mount to body bolts.(6) Position transmission jack to driveline module
assembly and secure assembly to jack.
(7) Remove two driveline module-to-body bolts
(Fig. 3).
(8) Lower driveline module from vehicle and
remove from jack.
Fig. 2 Half Shaft Mounting Bolts
1 - SHAFT
2 - FLANGE
Fig. 3 Rear Drive Line Module Assembly Mounting
Bolts
1 - DRIVELINE MODULE RETAINING BOLT (2)
2 - RUBBER ISOLATOR
3 - WASHER
3 - 26 REAR DRIVELINE MODULERS
REAR DRIVELINE MODULE (Continued)
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(5) Re-position the drain pan under the differential
fill plug.
(6) Remove the differential fill plug (Fig. 41).
(7) Using a suction gun (Fig. 42) or equivalent, fill
the differential assembly with 0.7 L (1.48 pts.) of
MopartGear and Axle Lubricant (80W-90).
(8) Install the fill plug and torque to 35 N´m (26 ft.
lbs.).
FLUID - OVERRUNNING
CLUTCH HOUSING
STANDARD PROCEDURE - OVERRUNNING
CLUTCH HOUSING FLUID CHANGE
(1) Raise vehicle on hoist.
(2) Position a drain pan under overrunning clutch
housing drain plug.
(3) Remove overrunning clutch housing drain plug
and drain fluid (Fig. 43).
(4) Install the drain plug and torque to 30 N´m (22
ft. lbs.).
(5) Re-position the drain pan under the overrun-
ning clutch housing fill plug.
(6) Remove fill plug (Fig. 44).
(7) Using a suction gun (Fig. 45), add 0.58 L (1.22
pts.) of MopartATF+4 (Automatic Transmission Flu-
idÐType 9602).
(8) Install fill plug and torque to 30 N´m (22 ft.
lbs.).
VISCOUS COUPLER
DESCRIPTION
The heart of the all-wheel drive system is the
inter-axle viscous coupling and bi-directional over-
running clutch. Under normal driving the vehicle
retains predominantly front wheel drive characteris-
tics. The all-wheel drive takes effect when the front
wheels start to slip. Under normal level road,
straight line driving, 100% of the torque is allocated
to the front wheels. The viscous coupler allows more
Fig. 42 Filling Differential
1 - DIFFERENTIAL ASSEMBLY
2 - SUCTION GUN
Fig. 43 Overrunning Clutch Case Drain Plug
1 - OVERRUNNING CLUTCH HOUSING DRAIN PLUG
Fig. 44 Overrunning Clutch Housing Fill Plug
1 - OVERRUNNING CLUTCH HOUSING FILL PLUG
2 - FUEL TANK
RSREAR DRIVELINE MODULE3-41
FLUID - DIFFERENTIAL ASSEMBLY (Continued)
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RED BRAKE WARNING INDICATOR LAMP
CONDITION POSSIBLE CAUSES CORRECTION
RED BRAKE WARNING
LAMP ON1. Parking brake lever not fully
released.1. Release parking brake lever.
2. Parking brake warning lamp
switch on parking brake lever.2. Inspect and replace switch as necessary.
3. Brake fluid level low in reservoir. 3. Fill reservoir. Check entire system for
leaks. Repair or replace as required.
4. Brake fluid level switch. 4. Disconnect switch wiring connector. If
lamp goes out, replace switch.
5. Mechanical instrument cluster
(MIC) problem.5. Refer to appropriate Diagnostic
information.
6. Amber ABS Warning Indicator
Lamp also illuminated.6. Refer to appropriate Diagnostic
information.
BRAKE NOISE
CONDITION POSSIBLE CAUSES CORRECTION
CLICK OR SQUAWK ON
PEDAL APPLICATION1. Brake lamp switch. 1. Replace switch.
2. Brake Transmission Shift Interlock
Linkage.2. Lubricate BTSI linkage.
3. Pedal pivot bushings 3. Lubricate pivot bushings. Replace if
necessary.
DISC BRAKE CHIRP 1. Excessive brake rotor runout. 1. Follow brake rotor diagnosis and testing.
Correct as necessary.
2. Lack of lubricant on brake caliper
slides.2. Lubricate brake caliper slides.
3. Caliper/shoes not fully seated. 3. Reseat caliper/shoes.
DISC BRAKE RATTLE OR
CLUNK1. Broken or missing anti-rattle
spring clips on shoes.1. Replace brake shoes.
2. Caliper guide pins/bolts loose. 2. Tighten guide pins/bolts.
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
MOAN1. 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 WHIRRING1. ABS wheel speed sensor or tone
wheel.1. Inspect, correct or replace faulty
component(s).
RSBRAKES - BASE5-5
BRAKES - BASE (Continued)
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master cylinder reservoir from completely draining
out.
(3) Disconnect the brake fluid flex hose from the
caliper assembly and remove it from the vehicle.
CAUTION: Do not use excessive force when clamp-
ing caliper in vise. Excessive vise pressure will
cause bore distortion.
(4) Mount the caliper in a vise equipped with pro-
tective jaws.
(5) Remove the piston dust boot from the caliper
and discard.
NOTE: Do not use a screw driver or other metal tool
for seal removal. Using such tools can scratch the
bore or leave burrs on the seal groove edges.
(6) Using a soft tool such as a plastic trim stick,
work the piston seal out of its groove in caliper pis-
ton bore (Fig. 33). Discard the old seal.
(7) Clean the piston bore and drilled passage ways
using alcohol or a suitable solvent. Wipe it dry using
only a lint-free cloth.
(8) Inspect the piston bore for scoring or pitting.
Bores that show light scratches or corrosion can usu-
ally be cleared of the light scratches or corrosion
using crocus cloth.CLEANING - CALIPER
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.
To clean or flush the internal passages of the brake
caliper, use fresh brake fluid or MopartNon-Chlori-
nated Brake Parts Cleaner. Never use gasoline, ker-
osene, alcohol, oil, transmission fluid or any fluid
containing mineral oil to clean the caliper. These flu-
ids will damage rubber cups and seals.
INSPECTION - CALIPER
Inspect the disc brake caliper for the following:
²Brake fluid leaks in and around boot area and
inboard lining
²Ruptures, brittleness or damage to the piston
dust boot
²Damaged, dry or brittle guide pin dust boots
If caliper fails inspection, disassemble and recondi-
tion caliper, replacing the seals and dust boots.
ASSEMBLY
ASSEMBLY - CALIPER GUIDE PIN BUSHINGS
(DISC/DISC BRAKES)
(1) Fold the guide pin bushing in half lengthwise.
NOTE: To avoid damage to the bushing, do not use
a sharp object to install the guide pin bushing.
(2) Insert the folded bushing into the caliper
mounting boss using your fingers from the rear of
the caliper.
Fig. 33 Removing Piston Seal
1 - PLASTIC TRIM STICK
2 - CALIPER
3 - PISTON SEAL GROOVE
4 - PISTON SEAL
RSBRAKES - BASE5-25
DISC BRAKE CALIPER - FRONT (Continued)
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NOTE: Do not use a screw driver or other metal tool
for seal removal. Using such tools can scratch the
bore or leave burrs on the seal groove edges.
(6) Using a soft tool such as a plastic trim stick,
work the piston seal out of its groove in caliper pis-
ton bore (Fig. 39). Discard the old seal.
(7) Clean the piston bore and drilled passage ways
using alcohol or a suitable solvent. Wipe it dry using
only a lint-free cloth.
(8) Inspect the piston bore for scoring or pitting.
Bores that show light scratches or corrosion can usu-
ally be cleared of the light scratches or corrosion
using crocus cloth.
CLEANING - CALIPER
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 AFINE 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.
To clean or flush the internal passages of the brake
caliper, use fresh brake fluid or MopartNon-Chlori-
nated Brake Parts Cleaner. Never use gasoline, ker-
osene, alcohol, oil, transmission fluid or any fluid
containing mineral oil to clean the caliper. These flu-
ids will damage rubber cups and seals.
INSPECTION - CALIPER
Inspect the disc brake caliper for the following:
²Brake fluid leaks in and around boot area and
inboard lining
²Ruptures, brittleness or damage to the piston
dust boot
²Damaged, dry or brittle guide pin dust boots
If caliper fails inspection, disassemble and recondi-
tion caliper, replacing the seals and dust boots.
ASSEMBLY - CALIPER PISTON AND SEAL
NOTE: Never use an old piston seal.
(1) Dip the new piston seal in clean brake fluid
and install it in the groove of the caliper bore. The
seal should be started at one area of the groove and
gently worked around and into the groove (Fig.
40)using only your clean fingers to seat it.
(2) Coat the new piston boot with clean brake
fluid.
(3) Position the dust boot over the piston after
coating it with brake fluid.
CAUTION: Force applied to the piston to seat it in
the bore must be applied uniformly to avoid cock-
ing and binding of the piston.
(4) Install piston into caliper bore pushing it past
the piston seal until it bottoms in the caliper bore
(Fig. 41).
(5) Position the dust boot into the counterbore of
the caliper assembly piston bore.
(6) Using a hammer and Installer, Special Tool
C-4689 or C-4842 (depending on piston size), and
Handle, Special Tool C-4171, drive the boot into the
counterbore of the caliper as necessary (Fig. 42).
Fig. 39 Removing Piston Seal
1 - PLASTIC TRIM STICK
2 - CALIPER
3 - PISTON SEAL GROOVE
4 - PISTON SEAL
RSBRAKES - BASE5-29
DISC BRAKE CALIPER - REAR (Continued)
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Use only brake fluid that was stored in a tightly-
sealed container.
DO NOTuse petroleum-based fluid because seal
damage will result. Petroleum based fluids would be
items such as engine oil, transmission fluid, power
steering fluid etc.
SPECIFICATIONS
BRAKE FLUID
The brake fluid used in this vehicle must conform
to DOT 3 specifications (DOT 4 and DOT 4+ are
acceptable) and SAE J1703 standards. No other type
of brake fluid is recommended or approved for usage
in the vehicle brake system. Use only MopartBrake
Fluid or equivalent from a tightly sealed container.
CAUTION: Never use reclaimed brake fluid or fluid
from an container which has been left open. An
open container of brake fluid will absorb moisture
from the air and contaminate the fluid.
CAUTION: Never use any type of a petroleum-based
fluid in the brake hydraulic system. Use of such
type fluids will result in seal damage of the vehicle
brake hydraulic system causing a failure of the
vehicle brake system. Petroleum based fluids would
be items such as engine oil, transmission fluid,
power steering fluid, etc.
JUNCTION BLOCK
DESCRIPTION - NON-ABS JUNCTION BLOCK
A junction block is used on vehicles that are not
equipped with antilock brakes (ABS). The junction
block mounts in the same location as the integrated
control unit (ICU) does on vehicles equipped with
ABS. This allows for use of the same brake tube con-
figuration on all vehicles. The junction block is
located on the driver's side of the front suspension
cradle/crossmember below the master cylinder (Fig.
45).
It has six threaded ports to which the brake tubes
connect. Two are for the primary and secondary
brake tubes coming from the master cylinder. The
remaining four are for the chassis brake tubes going
to each brake assembly.
OPERATION - NON-ABS JUNCTION BLOCK
The junction block distributes the brake fluid com-
ing from the master cylinder primary and secondary
ports to the four chassis brake tubes leading to the
brakes at each wheel. Since the junction blockmounts in the same location as the ABS integrated
control unit (ICU), it allows for the common use of
brake tubes going to the brakes whether the vehicle
is equipped with or without ABS.
NOTE: Although the brake tubes coming from the
master cylinder to the junction block or ABS ICU
may appear to be the same, they are not. They are
unique to each brake system application.
REMOVAL - NON-ABS JUNCTION BLOCK
(1) Using a brake pedal depressor, move and lock
the brake pedal to a position past its first 1 inch of
travel. This will prevent brake fluid from draining
out of the master cylinder when the brake tubes are
removed from the junction block.
(2) Disconnect the battery negative cable.
(3) If the vehicle is equipped with speed control,
perform the following:
(a) Disconnect the battery positive cable.
(b) Remove the battery (Refer to 8 - ELECTRI-
CAL/BATTERY SYSTEM/BATTERY - REMOVAL).
(c) Disconnect the vacuum hose connector at the
tank built into the battery tray.
(d) Remove the screw securing the coolant filler
neck to the battery tray.
(e) Remove the battery tray (Refer to 8 - ELEC-
TRICAL/BATTERY SYSTEM/TRAY - REMOVAL).
(f) Remove the fasteners and move the speed
control servo off to the side, out of the way.
CAUTION: Before removing the brake tubes from
the junction block, the junction block and the brake
tubes must be thoroughly cleaned. This is required
to prevent contamination from entering the brake
hydraulic system.
(4) Remove the four chassis brake tubes from the
top of the junction block (Fig. 45).
(5) Remove the primary and secondary brake
tubes from the top of the junction block.
(6) Remove the bolts attaching the junction block
mounting bracket to the front suspension crossmem-
ber (Fig. 45), then remove the junction block.
INSTALLATION - NON-ABS JUNCTION BLOCK
(1) Install the junction block and mounting bracket
on the front suspension crossmember (Fig. 45).
Install the mounting bolts and tighten to a torque of
28 N´m (250 in. lbs.).
(2) Install the primary and secondary brake tubes
from the master cylinder in their ports. Tighten tube
nuts to a torque of 17 N´m (145 in. lbs.).Take care
not to twist tubes when tightening tube nuts.
They must be properly positioned to allow free
RSBRAKES - BASE5-33
FLUID (Continued)
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tioning valve. The EVBP system uses the ABS sys-
tem to control the slip of the rear wheels in partial
braking range. The braking force of the rear wheels
is controlled electronically by using the inlet and out-
let valves located in the integrated control unit
(ICU).
EVBP activation is invisible to the customer since
there is no pump motor noise or brake pedal feed-
back.
DESCRIPTION - TRACTION CONTROL SYSTEM
Traction control reduces wheel slip and maintains
traction at the driving wheels at speeds below 56
km/h (35 mph) when road surfaces are slippery. The
traction control system reduces wheel slip by braking
the wheel that is losing traction.
HYDRAULIC SHUTTLE VALVES
Two pressure relief hydraulic shuttle valves are
included on vehicles with traction control. These
valves are located inside the HCU and cannot be ser-
viced separately from the HCU.
TRACTION CONTROL LAMP
The traction control function lamp is located in the
transmission range indicator display of the instru-
ment cluster, displaying TRAC, TRAC OFF or nei-
ther depending on system mode.
The TRAC OFF lamp is controlled by a Traction
Control Off switch that is a momentary contact type
switch. The Traction Control Off switch is located on
the steering column upper shroud.
OPERATION
OPERATION - ANTILOCK BRAKE SYSTEM
There are a few performance characteristics of the
Mark 20e Antilock Brake System that may at first
seem abnormal, but in fact are normal. These char-
acteristics are described below.
NORMAL BRAKING
Under normal braking conditions, the ABS func-
tions the same as a standard base brake system with
a diagonally split master cylinder and conventional
vacuum assist.
ABS BRAKING
ABS operation is available at all vehicle speeds
above 3±5 mph. If a wheel locking tendency is
detected during a brake application, the brake system
enters the ABS mode. During ABS braking, hydraulic
pressure in the four wheel circuits is modulated to
prevent any wheel from locking. Each wheel circuit is
designed with a set of electric solenoids to allow mod-ulation, although for vehicle stability, both rear wheel
solenoids receive the same electrical signal. Wheel
lockup may be perceived at the very end of an ABS
stop and is considered normal.
During an ABS stop, the brakes hydraulic system
is still diagonally split. However, the brake system
pressure is further split into three control channels.
During antilock operation of the vehicle's brake sys-
tem, the front wheels are controlled independently
and are on two separate control channels, and the
rear wheels of the vehicle are controlled together.
The system can build and release pressure at each
wheel, depending on signals generated by the wheel
speed sensors (WSS) at each wheel and received at
the controller antilock brake (CAB).
NOISE AND BRAKE PEDAL FEEL
During ABS braking, some brake pedal movement
may be felt. In addition, ABS braking will create
ticking, popping, or groaning noises heard by the
driver. This is normal and is due to pressurized fluid
being transferred between the master cylinder and
the brakes. If ABS operation occurs during hard
braking, some pulsation may be felt in the vehicle
body due to fore and aft movement of the suspension
as brake pressures are modulated.
At the end of an ABS stop, ABS is turned off when
the vehicle is slowed to a speed of 3±4 mph. There
may be a slight brake pedal drop anytime that the
ABS is deactivated, such as at the end of the stop
when the vehicle speed is less than 3 mph or during
an ABS stop where ABS is no longer required. These
conditions exist when a vehicle is being stopped on a
road surface with patches of ice, loose gravel, or sand
on it. Also, stopping a vehicle on a bumpy road sur-
face activates ABS because of the wheel hop caused
by the bumps.
TIRE NOISE AND MARKS
Although the ABS system prevents complete wheel
lockup, some wheel slip is desired in order to achieve
optimum braking performance. Wheel slip is defined
as follows: 0 percent slip means the wheel is rolling
freely and 100 percent slip means the wheel is fully
locked. During brake pressure modulation, wheel slip
is allowed to reach up to 25±30 percent. This means
that the wheel rolling velocity is 25±30 percent less
than that of a free rolling wheel at a given vehicle
speed. This slip may result in some tire chirping,
depending on the road surface. This sound should not
be interpreted as total wheel lockup.
Complete wheel lockup normally leaves black tire
marks on dry pavement. The ABS will not leave dark
black tire marks since the wheel never reaches a
fully locked condition. However, tire marks may be
noticeable as light patched marks.
5 - 76 BRAKES - ABSRS
BRAKES - ABS (Continued)
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