FLUID
DIAGNOSIS AND TESTING - BRAKE FLUID
CONTAMINATION
Indications of fluid contamination are swollen or
deteriorated rubber parts.
Swollen rubber parts indicate the presence of
petroleum in the brake fluid.
To test for contamination, put a small amount of
drained brake fluid in clear glass jar. If fluid sepa-
rates into layers, there is mineral oil or other fluid
contamination of the brake fluid.
If brake fluid is contaminated, drain and thor-
oughly flush system. Replace master cylinder, propor-
tioning valve, caliper seals, wheel cylinder seals,
Antilock Brake hydraulic unit and all hydraulic fluid
hoses.
STANDARD PROCEDURE - BRAKE FLUID
LEVEL CHECKING
Check master cylinder reservoir fluid level a mini-
mum of twice annually.
Fluid reservoirs are marked with the words FULL
and ADD to indicate proper brake fluid fill level of
the master cylinder.
If necessary, add brake fluid to bring the level to
the bottom of the FULL mark on the side of the mas-
ter cylinder fluid reservoir.
Use only Mopartbrake fluid or equivalent from a
sealed container. Brake fluid must conform to DOT 3
specifications (DOT 4 or DOT 4+ are acceptable).
DO NOTuse brake fluid with a lower boiling
point, as brake failure could result during prolonged
hard braking.
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.
44).
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 block
mounts 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.
RSBRAKES - BASE5-33
the park brake in this position, install a pair of lock-
ing pliers on the front parking brake cable just rear-
ward of the second body outrigger bracket (Fig. 97).
(2) Install the equalizer on the front parking brake
cable.
(3) Install the left rear and intermediate park
brake cable in the correct location on the parking
brake cable equalizer (Fig. 98).
(4) Remove the locking pliers from the front park-
ing brake cable. This will allow the adjuster in the
park brake lever (pedal) mechanism to tension the
park brake cables.
(5) Apply and release the parking brake lever
(pedal) one time. This will seat the parking brake
cables and allow the auto adjuster in the parking
brake lever (pedal) mechanism to correctly tension
the parking brake cables.
STANDARD PROCEDURE - CABLE END
CLEANING AND LUBRICATION
Periodic cleaning and lubrication can be done to
ensure proper operation of the parking brake cables.This procedure applies to the trailing end of all park-
ing brake cables.
CAUTION: If a liquid cleaner is necessary, use a
cleaner such as MoparTNon-Chlorinated Brake
Parts Cleaner or equivalent.
(1) Using an appropriate bristle brush, clean the
cable strand in the area that retracts into the cable
housing when the parking brake lever is applied (Fig.
99).
(2) Clean the cable seal area at the end of the
cable housing (Fig. 99).
(3) Lubricate the cleaned area with a general pur-
pose grease lubricant.
ADJUSTMENTS
ADJUSTMENT - PARKING BRAKE CABLES
The park brake cables on this vehicle have an
automatic self adjuster built into the park brake
pedal mechanism. When the foot operated park brake
pedal is in its released (upward most) position, a
clock spring automatically adjusts the park brake
cables. The park brake cables are adjusted (ten-
sioned) just enough to remove all the slack from the
cables. The automatic adjuster system will not over
adjust the cables causing rear brake drag.
Due to the automatic adjust feature of the park
brake pedal, adjustment of the parking brake cables
on these vehicles relies on proper drum brake and
park brake shoe adjustment. (Refer to 5 - BRAKES/
HYDRAULIC/MECHANICAL/DRUM - ADJUST-
MENTS) and (Refer to 5 - BRAKES/PARKING
BRAKE/SHOES - ADJUSTMENTS).
When the park brake pedal is applied the self
adjuster is by-passed and the pedal operates nor-
mally to engage the park brakes.
When a service procedure needs to be performed on
the park brake pedal or the park brake cables, the
automatic self adjuster can be manually locked out
by the service technician.
Fig. 99 Areas To Be Cleaned And Lubricated
1 - STRAND AREA
2 - SEAL AREA
RSBRAKES - BASE5-65
PARKING BRAKE (Continued)
CABLE - PARKING BRAKE
INTERMEDIATE
REMOVAL
(1) Raise and support the vehicle. (Refer to
LUBRICATION & MAINTENANCE/HOISTING -
STANDARD PROCEDURE).
(2) Manually lock out the automatic self-adjusting
mechanism tension of the parking brake lever (pedal)
assembly. (Refer to 5 - BRAKES - STANDARD PRO-
CEDURE). Once the cable is released from the equal-
izer, do not remove the locking pliers until
reinstallation of the cable is complete.
(3) Remove the intermediate parking brake cable
from the parking brake cable equalizer (Fig. 108).
(4) Remove the locking nut securing the interme-
diate cable housing to the side bracket on the frame
rail (Fig. 108).
(5) Remove the intermediate parking brake cable
from the cable connector attaching it to the right
rear parking brake cable (Fig. 109). Remove the lock-
ing nut securing the intermediate cable housing to
the side bracket on the frame rail (Fig. 109).
(6) If the vehicle is a short-wheel-base model, it
will be necessary to loosen and lower the fuel tank
far enough to remove the intermediate parking brake
cable. (Refer to 14 - FUEL SYSTEM/FUEL DELIV-
ERY/FUEL TANK - REMOVAL).
(7) Remove the intermediate parking brake cable
from the side brackets and vehicle.
INSTALLATION
(1) Install the ends of the park brake cables
through the frame rails and into the side brackets.
(2) Install the locking nuts at each end of the cable
and securely tighten (Fig. 108) (Fig. 109).
(3) If the vehicle is a short-wheel-base model, it
will be necessary to reinstall the fuel tank to its nor-
mal mounting position. (Refer to 14 - FUEL SYS-
TEM/FUEL DELIVERY/FUEL TANK -
INSTALLATION).
(4) Install the intermediate parking brake cable on
the cable connector at the right rear parking brake
cable (Fig. 109).
(5) Install the intermediate park brake cable on
the cable equalizer (Fig. 108).
(6) Remove the locking pliers from the front park
brake cable. This will activate the automatic adjuster
and correctly adjust the parking brake cables.
(7) Install and position the foam collar on the
parking brake cable to prevent it from rattling
against the vehicle's floor.
(8) Lower the vehicle and apply the park brake
pedal 1 time, this will seat the park brake cables.
Fig. 108 Parking Brake Cable Attachment To
Equalizer
1 - EQUALIZER
2 - LEFT REAR PARKING BRAKE CABLE
3 - LOCKING NUT
4 - INTERMEDIATE PARKING BRAKE CABLE
5 - FRONT PARKING BRAKE CABLE
Fig. 109 Intermediate Cable Attachment To Right
1 - RIGHT REAR PARKING BRAKE CABLE
2 - LOCKING NUT
3 - INTERMEDIATE PARKING BRAKE CABLE
RSBRAKES - BASE5-69
CAUTION: Corrosion may occur between the hub/
bearing and the axle flange. If this occurs, the hub/
bearing will be difficult to remove from the axle and
disc brake caliper adapter. If the hub/bearing will
not come out by pulling on it by hand, don't not
pound on it with a hammer. Pounding on the hub/
bearing will damage it. To remove a hub/bearing
that is corroded in place, lightly tap the disc brake
caliper adapter using a soft-face hammer. This will
remove both the caliper adapter and hub/bearing
together from the axle. With a helper supporting the
caliper adapter in his hands, position Remover,
Special Tool 8214-1, on the cast housing of hub/
bearing (Fig. 141). Do not position the special tool
on the inner race of hub/bearing. Lightly strike the
Remover with a hammer to remove the hub/bearing
from the caliper adapter.
(20) Remove the adapter from the rear axle.
(21) Mount the adapter in a vise using the anchor
boss for the park brake cable (Fig. 142).
(22) Remove the lower return spring (Fig. 143)
from the leading and trailing park brake shoes.
Fig. 141 Hub/Bearing Removal From Caliper Adapter
1 - SPECIAL TOOL 8214-1
2 - PARK BRAKE CABLE
3 - DISC BRAKE CALIPER ADAPTER
4 - HUB/BEARING
Fig. 142 Adapter Mounted In Vise
1 - ADAPTER
2 - PARK BRAKE CABLE BOSS
3 - VISE
4 - PARK BRAKE BRAKE SHOES
Fig. 143 Lower Return Spring
1 - ADAPTER
2 - LEADING PARK BRAKE SHOE
3 - RETURN SPRING
4 - TRAILING PARK BRAKE SHOE
5 - 82 BRAKES - BASERS
SHOES - PARKING BRAKE (Continued)
(23) Remove the hold down spring and pin (Fig.
144) from the leading park brake shoe.
(24) Remove the adjuster (Fig. 145) from the lead-
ing and trailing park brake shoe.(25) Remove the leading park brake shoe (Fig.
146) from the adapter. Leading brake shoe is
removed by rotating the bottom of the brake shoe
inward (Fig. 146) until the top of the brake shoe can
be removed from the brake shoe anchor. Then remove
the upper return springs (Fig. 146) from the leading
brake shoe.
(26) Remove the upper return springs (Fig. 147)
from the trailing park brake shoe.
Fig. 144 Leading Brake Shoe Hold Down Pin And
Spring
1 - ADAPTER
2 - LEADING PARK BRAKE SHOE
3 - ALLEN WRENCH
4 - HOLD DOWN SPRING/PIN
Fig. 145 Brake Shoe Adjuster
1 - LEADING PARK BRAKE SHOE
2 - ADJUSTER
3 - TRAILING PARK BRAKE SHOE
Fig. 146 Primary Brake Shoe Remove/Install
1 - PARK BRAKE ACTUATOR
2 - ANCHOR
3 - LEADING PARK BRAKE SHOE
4 - UPPER RETURN SPRINGS
5 - TRAILING PARK BRAKE SHOE
Fig. 147 Upper Return Springs
1 - TRAILING PARK BRAKE SHOE
2 - ADAPTER
3 - PARK BRAKE ACTUATOR
4 - UPPER RETURN SPRINGS
RSBRAKES - BASE5-83
SHOES - PARKING BRAKE (Continued)
(27) Remove the hold down spring and pin (Fig.
148) from the trailing park brake shoe.
(28) Remove the trailing park brake shoe from the
adapter.
(29) Remove the park brake shoe actuator from
the adapter and inspect for signs of abnormal wear
and binding at the pivot point.
INSTALLATION
(1) Install park brake shoe actuator into adapter.
(2) Install the trailing brake shoe on the adapter.
NOTE: When the hold down pin is installed, the
long part of the hold down pin is to be positioned
strait up and down. This will ensure that the hold
down pin is correctly engaged with the adapter.
(3) Install the hold down spring and pin (Fig. 148)
on the trailing park brake shoe.
(4) Install the upper return springs (Fig. 147) on
the trailing park brake shoe.
(5) Install the upper return springs on the leading
park brake shoe (Fig. 146). Then position the top of
the leading park brake shoe at the upper anchor and
rotate the bottom of the shoe outward until correctly
installed on the adapter.
(6) Install the adjuster (Fig. 145) between the
leading and trailing park brake shoe.
NOTE: When the hold down pin is installed, the
long part of the hold down pin is to be positioned
strait up and down. This will ensure that the hold
down pin is correctly engaged with the adapter.(7) Install the hold down spring and pin (Fig. 144)
on the leading park brake shoe.
(8) Install the lower return spring (Fig. 143) on
the leading and trailing park brake shoes.When
installing the return spring, it is to be installed
behind the park brake shoes (Fig. 143).
(9) Install the 4 mounting bolts for the adapter
and hub/bearing into the bolt holes in the axle.
(10) Position the adapter on the 4 mounting bolts
installed in the rear axle (Fig. 149).
(11) Install the hub/bearing on the stub shaft of
outer C/V joint (AWD only) and into the end of the
axle. (Fig. 140).
(12) In a progressive crisscross pattern, tighten
the 4 hub/bearing mounting bolts until the hub/bear-
ing is squarely seated against the axle. Then tighten
the hub/bearing mounting bolts to a torque of 129
N´m (95 ft. lbs.).
(13) AWD only - Install the wheel speed sensor on
the hub/bearing and adapter. Install the wheel speed
sensor attaching bolt (Fig. 137). Tighten the wheel
speed sensor attaching bolt to a torque of 12 N´m
(105 in. lbs).
(14) FWD only - Install the wheel speed sensor in
the following fashion:
(a) If metal wheel speed sensor retaining clip is
not in the neutral installed position on hub and
bearing cap, install from the bottom, if necessary,
and push clip upward until it snaps into position.
(b) Install wheel speed sensor head into rear of
hub and bearing aligning index tab with the notch
in the top of the mounting hole. Push the sensor in
Fig. 148 Trailing Brake Shoe Hold Down Pin And
Spring
1 - HOLD DOWN SPRING PIN
2 - ADAPTER
3 - PARK BRAKE ACTUATOR
4 - TRAILING PARK BRAKE SHOE
5 - ALLEN WRENCH
Fig. 149 Adapter Installed On Mounting Bolts (AWD
Shown)
1 - DRIVESHAFT OUTER C/V JOINT
2 - MOUNTING BOLTS
3 - ADAPTER
4 - PARK BRAKE SHOES
5 - MOUNTING BOLTS
5 - 84 BRAKES - BASERS
SHOES - PARKING BRAKE (Continued)
DESCRIPTION - ELECTRONIC VARIABLE
BRAKE PROPORTIONING
Vehicles equipped with ABS use electronic variable
brake proportioning (EVBP) to balance front-to-rear
braking. The EVBP is used in place of a rear propor-
tioning valve. The EVBP system uses the ABS system
to control the slip of the rear wheels in partial brak-
ing range. The braking force of the rear wheels is con-
trolled electronically by using the inlet and outlet
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 feedback.
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 thefour wheel circuits is modulated to prevent any wheel
from locking. Each wheel circuit is designed with a set of
electric solenoids to allow modulation, although for vehi-
cle 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 surface 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 - 88 BRAKES - ABSRS
BRAKES - ABS (Continued)
CAUTION
The ABS uses an electronic control module, the
CAB. This module is designed to withstand normal
current draws associated with vehicle operation.
Care must be taken to avoid overloading the CAB
circuits.
CAUTION: In testing for open or short circuits, do
not ground or apply voltage to any of the circuits
unless instructed to do so for a diagnostic proce-
dure.
CAUTION: These circuits should only be tested
using a high impedance multi-meter or the DRBIIIT
scan tool as described in this section. Power
should never be removed or applied to any control
module with the ignition in the ON position. Before
removing or connecting battery cables, fuses, or
connectors, always turn the ignition to the OFF
position.
CAUTION: The CAB 24-way connector should never
be connected or disconnected with the ignition
switch in the ON position.
CAUTION: This vehicle utilizes active wheel speed
sensors. Do not apply voltage to wheel speed sen-
sors at any time.
CAUTION: Use only factory wiring harnesses. Do
not cut or splice wiring to the brake circuits. The
addition of aftermarket electrical equipment (car
phone, radar detector, citizen band radio, trailer
lighting, trailer brakes, etc.) on a vehicle equipped
with antilock brakes may affect the function of the
antilock brake system.
CAUTION: When performing any service procedure
on a vehicle equipped with ABS, do not apply a
12-volt power source to the ground circuit of the
pump motor in the HCU. Doing this will damage the
pump motor and will require replacement of the
entire HCU.
CAUTION: An attempt to remove or disconnect cer-
tain system components may result in improper
system operation. Only those components with
approved removal and installation procedures in
this manual should be serviced.
CAUTION: If welding work is to be performed on the
vehicle using an electric arc welder, the CAB con-nector should be disconnected during the welding
operation.
CAUTION: Many components of the ABS System
are not serviceable and must be replaced as an
assembly. Do not disassemble any component
which is not designed to be serviced.
CAUTION: Only the recommended jacking or hoist-
ing positions for this vehicle are to be used when-
ever it is necessary to lift a vehicle. Failure to raise
a vehicle from the recommended locations could
result in lifting a vehicle by the hydraulic control
unit mounting bracket. Lifting a vehicle by the
hydraulic control unit mounting bracket will result
in damage to the mounting bracket and the hydrau-
lic control unit.
CAUTION: Brake fluid will damage painted surfaces.
If brake fluid is spilled on any painted surface,
wash off with water immediately.
STANDARD PROCEDURE - ANTILOCK BRAKE
SYSTEM BLEEDING
The base brake's hydraulic system must be bled
anytime air enters the hydraulic system. The ABS
though, particularly the ICU (HCU), should only be
bled when the HCU is replaced or removed from the
vehicle. The ABS must always be bled anytime it is
suspected that the HCU has ingested air. Under
most circumstances that require the bleeding of the
brakes hydraulic system, only the base brake
hydraulic system needs to be bled.
It is important to note that excessive air in the
brake system will cause a soft or spongy feeling
brake pedal.
During the brake bleeding procedure, be sure the
brake fluid level remains close to the FULL level in
the master cylinder fluid reservoir. Check the fluid
level periodically during the bleeding procedure and
add DOT 3 brake fluid as required.
The ABS must be bled as two independent braking
systems. The non-ABS portion of the brake system
with ABS is to be bled the same as any non-ABS sys-
tem.
The ABS portion of the brake system must be bled
separately. Use the following procedure to properly
bleed the brake hydraulic system including the ABS.
BLEEDING
When bleeding the ABS system, the following
bleeding sequence must be followed to insure com-
plete and adequate bleeding.
5 - 90 BRAKES - ABSRS
BRAKES - ABS (Continued)