standard equipment. Disc brake components consist
of single piston calipers and ventilated rotors. Rear
drum brakes are dual shoe units with cast brake
drums.

The parking brake mechanism is lever and cable

operated. The cables are attached to levers on the
rear drum brake secondary shoes. The parking
brakes are operated by a hand lever.

A dual diaphragm vacuum power brake booster is

used for all applications. All models have an alumi-
num master cylinder with plastic reservoir.

All models are equipped with a combination valve.

The valve contains a pressure differential valve and
switch and a fixed rate rear proportioning valve.

Factory brake lining on all models consists of an

organic base material combined with metallic parti-
cles. The original equipment linings do not contain
asbestos.

5 - 2

BRAKES - BASE

DESCRIPTION - SERVICE WARNINGS &
CAUTIONS

WARNING: DUST AND DIRT ACCUMULATING ON
BRAKE PARTS DURING NORMAL USE MAY CON-
TAIN ASBESTOS FIBERS FROM PRODUCTION OR
AFTERMARKET LININGS. BREATHING EXCESSIVE
CONCENTRATIONS OF ASBESTOS FIBERS CAN
CAUSE SERIOUS BODILY HARM. EXERCISE CARE
WHEN SERVICING BRAKE PARTS. DO NOT CLEAN
BRAKE PARTS WITH COMPRESSED AIR OR BY
DRY BRUSHING. USE A VACUUM CLEANER SPE-
CIFICALLY DESIGNED FOR THE REMOVAL OF
ASBESTOS FIBERS FROM BRAKE COMPONENTS.
IF A SUITABLE VACUUM CLEANER IS NOT AVAIL-
ABLE, CLEANING SHOULD BE DONE WITH A
WATER DAMPENED CLOTH. DO NOT SAND, OR
GRIND BRAKE LINING UNLESS EQUIPMENT USED
IS DESIGNED TO CONTAIN THE DUST RESIDUE.
DISPOSE OF ALL RESIDUE CONTAINING ASBES-
TOS FIBERS IN SEALED BAGS OR CONTAINERS
TO MINIMIZE EXPOSURE TO YOURSELF AND OTH-
ERS. FOLLOW PRACTICES PRESCRIBED BY THE
OCCUPATIONAL SAFETY AND HEALTH ADMINIS-
TRATION AND THE ENVIRONMENTAL PROTECTION
AGENCY FOR THE HANDLING, PROCESSING, AND
DISPOSITION OF DUST OR DEBRIS THAT MAY
CONTAIN ASBESTOS FIBERS.

CAUTION: Never use gasoline, kerosene, alcohol,
motor oil, transmission fluid, or any fluid containing
mineral oil to clean the system components. These
fluids damage rubber cups and seals. Use only
fresh brake fluid or Mopar brake cleaner to clean or
flush brake system components. These are the only
cleaning materials recommended. If system contam-
ination is suspected, check the fluid for dirt, discol-
oration, or separation into distinct layers. Also
check the reservoir cap seal for distortion. Drain
and flush the system with new brake fluid if con-
tamination is suspected.

CAUTION: Use Mopar brake fluid, or an equivalent
quality fluid meeting SAE/DOT standards J1703 and
DOT 3. Brake fluid must be clean and free of con-
taminants. Use fresh fluid from sealed containers
only to ensure proper antilock component opera-
tion.

CAUTION: Use Mopar multi-mileage or high temper-
ature grease to lubricate caliper slide surfaces,
drum brake pivot pins, and shoe contact points on
the backing plates. Use multi-mileage grease or GE

661 or Dow 111 silicone grease on caliper slide pins
to ensure proper operation.

DIAGNOSIS AND TESTING - BASE BRAKE
SYSTEM

Base brake components consist of the brake shoes,

calipers, wheel cylinders, brake drums, rotors, brake
lines, master cylinder, booster, and parking brake
components.

Brake diagnosis involves determining if the prob-

lem is related to a mechanical, hydraulic, or vacuum
operated component.

The first diagnosis step is the preliminary check.

PRELIMINARY BRAKE CHECK

(1) Check condition of tires and wheels. Damaged

wheels and worn, damaged, or underinflated tires
can cause pull, shudder, vibration, and a condition
similar to grab.

(2) If complaint was based on noise when braking,

check suspension components. Jounce front and rear
of vehicle and listen for noise that might be caused
by loose, worn or damaged suspension or steering
components.

(3) Inspect brake fluid level and condition. Note

that the front disc brake reservoir fluid level will
decrease in proportion to normal lining wear. Also
note that brake fluid tends to darken over time.
This is normal and should not be mistaken for
contamination.

(a) If fluid level is abnormally low, look for evi-

dence of leaks at calipers, wheel cylinders, brake
lines, and master cylinder.

(b) If fluid appears contaminated, drain out a

sample. System will have to be flushed if fluid is
separated into layers, or contains a substance
other than brake fluid. The system seals and cups
will also have to be replaced after flushing. Use
clean brake fluid to flush the system.
(4) Check parking brake operation. Verify free

movement and full release of cables and pedal. Also
note if vehicle was being operated with parking
brake partially applied.

(5) Check brake pedal operation. Verify that pedal

does not bind and has adequate free play. If pedal
lacks free play, check pedal and power booster for
being loose or for bind condition. Do not road test
until condition is corrected.

(6) If components checked appear OK, road test

the vehicle.

ROAD TESTING

(1) If complaint involved low brake pedal, pump

pedal and note if it comes back up to normal height.

BRAKES - BASE

5 - 3

BRAKES - BASE (Continued)

(2) Check brake pedal response with transmission

in Neutral and engine running. Pedal should remain
firm under constant foot pressure.

(3) During road test, make normal and firm brake

stops in 25-40 mph range. Note faulty brake opera-
tion such as low pedal, hard pedal, fade, pedal pulsa-
tion, pull, grab, drag, noise, etc.

PEDAL FALLS AWAY

A brake pedal that falls away under steady foot

pressure is generally the result of a system leak. The
leak point could be at a brake line, fitting, hose, or
caliper/wheel cylinder. Internal leakage in the master
cylinder caused by worn or damaged piston cups,
may also be the problem cause.

If leakage is severe, fluid will be evident at or

around the leaking component. However, internal
leakage in the master cylinder may not be physically
evident.

LOW PEDAL

If a low pedal is experienced, pump the pedal sev-

eral times. If the pedal comes back up, worn lining,
rotors, or drums are the most likely causes.

SPONGY PEDAL

A spongy pedal is most often caused by air in the

system. However, thin brake drums or substandard
brake lines and hoses can also cause a spongy pedal.
The proper course of action is to bleed the system, or
replace thin drums and suspect quality brake lines
and hoses.

HARD PEDAL OR HIGH PEDAL EFFORT

A hard pedal or high pedal effort may be due to

lining that is water soaked, contaminated, glazed, or
badly worn. The power booster or check valve could
also be faulty.

PEDAL PULSATION

Pedal pulsation is caused by components that are

loose, or beyond tolerance limits.

The primary cause of pulsation are disc brake

rotors with excessive lateral runout or thickness vari-
ation, or out of round brake drums. Other causes are
loose wheel bearings or calipers and worn, damaged
tires.

NOTE: Some pedal pulsation may be felt during
ABS activation.

BRAKE DRAG

Brake drag occurs when the lining is in constant

contact with the rotor or drum. Drag can occur at one
wheel, all wheels, fronts only, or rears only.

Drag is a product of incomplete brake shoe release.

Drag can be minor or severe enough to overheat the
linings, rotors and drums.

Minor drag will usually cause slight surface char-

ring of the lining. It can also generate hard spots in
rotors and drums from the overheat-cool down pro-
cess. In most cases, the rotors, drums, wheels and
tires are quite warm to the touch after the vehicle is
stopped.

Severe drag can char the brake lining all the way

through. It can also distort and score rotors and
drums to the point of replacement. The wheels, tires
and brake components will be extremely hot. In
severe cases, the lining may generate smoke as it
chars from overheating.

Possible causes for brake drag condition are:
• Seized or improperly adjusted parking brake

cables.

• Loose/worn wheel bearing.

• Seized caliper or wheel cylinder piston.

• Caliper binding on corroded bushings or rusted

slide surfaces.

• Loose caliper mounting bracket.

• Drum brake shoes binding on worn/damaged

support plates.

• Mis-assembled components.
If brake drag occurs at all wheels, the problem

may be related to a blocked master cylinder return
port, or faulty power booster (binds-does not release).

BRAKE FADE

Brake fade is usually a product of overheating

caused by brake drag. However, brake overheating
and resulting fade can also be caused by riding the
brake pedal, making repeated high deceleration stops
in a short time span, or constant braking on steep
mountain roads. Refer to the Brake Drag information
in this section for causes.

BRAKE PULL

Possible causes for front brake pull condition are:
• Contaminated lining in one caliper.

• Seized caliper piston.

• Binding caliper.

• Loose caliper.

• Rusty adapter/caliper slide surfaces.

• Improper brake shoes.

• Damaged rotor.
A worn, damaged wheel bearing or suspension

component are further causes of pull. A damaged
front tire (bruised, ply separation) can also cause
pull.

A common and frequently misdiagnosed pull condi-

tion is where direction of pull changes after a few
stops. The cause is a combination of brake drag fol-
lowed by fade at one of the brake units.

5 - 4

BRAKES - BASE

BRAKES - BASE (Continued)

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