Dodge Brakes Repair Manual
BR/BE BRAKES 5 - 1
BRAKES
TABLE OF CONTENTS
page page
BRAKES - BASE ........................... 1 BRAKES - ABS ........................... 35
BRAKES - BASE
TABLE OF CONTENTS
page page
BRAKES - BASE
SPECIFICATIONS
BASE BRAKE .........................2
TORQUE CHART ......................3
SPECIAL TOOLS
BASE BRAKES ........................4
HYDRAULIC/MECHANICAL
DESCRIPTION ..........................4
WARNING .............................4
DIAGNOSIS AND TESTING - BASE BRAKE
SYSTEM .............................5
STANDARD PROCEDURE
STANDARD PROCEDURE - MANUAL
BLEEDING............................7
STANDARD PROCEDURE - PRESSURE
BLEEDING............................8
BRAKE LINES
STANDARD PROCEDURE
STANDARD PROCEDURE - DOUBLE
INVERTED FLARING ....................8
STANDARD PROCEDURE - ISO FLARING . . . 8
COMBINATION VALVE
DESCRIPTION ..........................8
OPERATION ............................9
DIAGNOSIS AND TESTING - COMBINATION
VALVE ...............................9
REMOVAL .............................9
INSTALLATION ..........................9
DISC BRAKE CALIPERS
DESCRIPTION .........................10
OPERATION ...........................10
REMOVAL
REMOVAL - REAR .....................10
REMOVAL - FRONT ....................11
DISASSEMBLY .........................11
CLEANING ............................12
INSPECTION ..........................12
ASSEMBLY ............................13
INSTALLATION
INSTALLATION - REAR .................14
INSTALLATION - FRONT ................14
FLUID
DIAGNOSIS AND TESTING - BRAKE FLUID
CONTAMINATION .....................15
STANDARD PROCEDURE - BRAKE FLUID
LEVEL ..............................15
SPECIFICATIONS
BRAKE FLUID ........................15
FLUID RESERVOIR
REMOVAL .............................15
INSTALLATION .........................15
PEDAL
DESCRIPTION .........................17
OPERATION ...........................17
REMOVAL .............................17
INSTALLATION .........................17
POWER BRAKE BOOSTER
DIAGNOSIS AND TESTING - HYDRAULIC
BOOSTER ...........................18
STANDARD PROCEDURE - BLEEDING ......19
REMOVAL .............................19
INSTALLATION .........................19
ROTORS
DIAGNOSIS AND TESTING
DISC BRAKE ROTOR ..................20
REMOVAL
REMOVAL - REAR .....................21
REMOVAL - FRONT – 2500 ..............22
REMOVAL - FRONT - 3500 ..............22
INSTALLATION
INSTALLATION - REAR .................22
INSTALLATION - FRONT – 2500 ..........23
INSTALLATION - FRONT - 3500 ...........23
5 - 2 BRAKES - BASE BR/BE
BRAKE PADS/SHOES
REMOVAL
REMOVAL - REAR .....................23
REMOVAL - FRONT ....................24
INSTALLATION
INSTALLATION - REAR .................25
INSTALLATION - FRONT ................26
MASTER CYLINDER
DESCRIPTION .........................26
OPERATION ...........................26
DIAGNOSIS AND TESTING - MASTER
CYLINDER/POWER BOOSTER ...........26
STANDARD PROCEDURE - MASTER
CYLINDER BLEEDING ..................27
REMOVAL .............................27
INSTALLATION .........................28
PARKING BRAKE
DESCRIPTION .........................28
OPERATION ...........................28
PEDAL
REMOVAL .............................28
INSTALLATION .........................29
BRAKES - BASE
SPECIFICATIONS
BASE BRAKE
SPECIFICATIONS
DESCRIPTION SPECIFICATION
Front/Rear Disc Brake
Caliper
Type
Front Disc Brake Caliper
Piston Diameter HD
Front Disc Brake Rotor 326.5×36 mm
Front/Rear Disc Brake
Rotor
Max. Runout
Front/Rear Disc Brake
Rotor
Max. Thickness Variation
Dual Piston Sliding
56 mm (2.00 in.)
(12.5×1.5 in.)
0.127 mm (0.005 in.)
0.025 mm (0.001 in.)
CABLES
REMOVAL
REMOVAL - REAR PARK BRAKE CABLE . . . 29
REMOVAL - FRONT PARKING BRAKE
CABLE..............................29
INSTALLATION
INSTALLATION - REAR PARK BRAKE
CABLE..............................30
INSTALLATION - FRONT PARKING BRAKE
CABLE..............................30
CABLE TENSIONER
ADJUSTMENTS
ADJUSTMENT ........................30
RELEASE HANDLE
REMOVAL .............................31
INSTALLATION .........................32
SHOES
REMOVAL .............................32
INSTALLATION .........................32
ADJUSTMENTS
ADJUSTMENT - PARKING BRAKE SHOES . . 33
DESCRIPTION SPECIFICATION
Minimum Front Rotor
Thickness
Mininium Rear Rotor
Thickness
Rear Disc Brake Caliper
2500
Rear Disc Brake Caliper
3500
Rear Disc Brake Rotor
2500/3500
Brake Booster
Type
2500 Gasoline Engines
Brake Booster
Type
All 3500/
2500 Diesel Engines
Only
33.90 mm (1.334 in.)
28.39 mm (1.117 in)
2x45 mm (1.77 in)
2x51 mm (2.00 in)
323.5x30 mm (1.18 in)
Vacuum Dual Diaphragm
Hydraulic
BR/BE BRAKES - BASE 5 - 3
BRAKES - BASE (Continued)
TORQUE CHART
TORQUE SPECIFICATIONS
DESCRIPTION N·m Ft. Lbs. In. Lbs.
Booster
Mounting Nuts To
Dashpanel
Master Cylinder
Mounting Nuts
Master Cylinder
Brake Lines
Combination Valve
Mounting Bolt
Combination Valve
Brake Lines
Proportioning Valve
Mounting Nuts
Proportioning Valve
Brake Hose
Proportioning Valve
Brake Lines
Front Caliper
Mounting Bolts
Front Caliper
HD Adapter Bolts
Rear Caliper
Slide Pins
Rotor to Hub Rear
Bolt
All Caliper
Banjo Bolts
Support Plate
Mounting Bolts
Park Brake Pedal
Assembly
Mounting Bolts/Nuts
Hub/Bearing
HD 4x2 Spindle Nut
Hub/Bearing
4x4 Hub/Bearing Bolts
28 21 250
23 17 200
21 16 190
23 17 210
21 16 190
34 25 300
31 23 276
21 16 190
33 24 —
285 210 —
33 24 300
128 95 —
40 30 360
58 43 —
28 21 250
380 280 —
170 125 —
5 - 4 BRAKES - BASE BR/BE
BRAKES - BASE (Continued)
SPECIAL TOOLS
BASE BRAKES
Installer, Brake Caliper Dust Boot C-4340
Installer, Brake Caliper Dust Boot C-3716-A
HYDRAULIC/MECHANICAL
DESCRIPTION
This vehicle is equipped with front disc brakes and
rear drum brakes also certain vehicles have four
wheel disc brakes. The front and rear disc brakes
consist of dual piston calipers and ventilated rotors.
The rear brakes are dual brake shoe, internal
expanding units with cast brake drums. The parking
brake mechanism is cable operated and connected to
the rear brake trailing shoes. Power brake assist is
standard equipment. A vacuum operated power brake
booster is used on gas engine vehicles. A hydraulic
booster is used on diesel engine vehicles.
Two antilock brake systems are used on this vehicle. A rear wheel antilock (RWAL) brake system and
all-wheel antilock brake system (ABS). The RWAL
and ABS systems are designed to retard wheel
lockup while braking. Retarding wheel lockup is
accomplished by modulating fluid pressure to the
wheel brake units. Both systems are monitored by a
microprocessor which controls the operation of the
systems.
Handle C-4171
Cap, Master Cylinder Pressure Bleed 6921
WARNING
WARNING: DUST AND DIRT ACCUMULATING ON
BRAKE PARTS DURING NORMAL USE MAY CONTAIN 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 SPECIFICALLY DESIGNED FOR THE REMOVAL OF
ASBESTOS FIBERS FROM BRAKE COMPONENTS.
IF A SUITABLE VACUUM CLEANER IS NOT AVAILABLE, 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 ASBESTOS FIBERS IN SEALED BAGS OR CONTAINERS
TO MINIMIZE EXPOSURE TO YOURSELF AND OTHERS. FOLLOW PRACTICES PRESCRIBED BY THE
OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION AND THE ENVIRONMENTAL PROTECTION
AGENCY FOR THE HANDLING, PROCESSING, AND
DISPOSITION OF DUST OR DEBRIS THAT MAY
CONTAIN ASBESTOS FIBERS.
BR/BE BRAKES - BASE 5 - 5
HYDRAULIC/MECHANICAL (Continued)
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 contamination is suspected, check the fluid for dirt, discoloration, or separation into distinct layers. Also
check the reservoir cap seal for distortion. Drain
and flush the system with new brake fluid if contamination 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 contaminants. Use fresh fluid from sealed containers
only to ensure proper antilock component operation.
CAUTION: Use Mopar multi-mileage or high temperature 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 problem 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 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 evidence of leaks at calipers, wheel cylinders, brake
lines, and master cylinder.
(b) If fluid appears contaminated, drain out a
sample to examine. 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) Check booster vacuum check valve and hose.
(7) 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.
(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 operation such as low pedal, hard pedal, fade, pedal pulsation, pull, grab, drag, noise, etc.
(4) Attempt to stop the vehicle with the parking
brake only and note 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. If leakage is severe, fluid will
be evident at or around the leaking component.
Internal leakage (seal by-pass) in the master cylin-
der caused by worn or damaged piston cups, may
also be the problem cause.
An internal leak in the ABS or RWAL system may
also be the problem with no physical evidence.
LOW PEDAL
If a low pedal is experienced, pump the pedal sev-
eral times. If the pedal comes back up, worn linings,
rotors, drums, or rear brakes out of adjustment are
the most likely causes. The proper course of action is
to inspect and replace all worn component and make
the proper adjustments.
5 - 6 BRAKES - BASE BR/BE
HYDRAULIC/MECHANICAL (Continued)
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,
and replace thin drums and substandard quality
brake hoses if suspected.
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 variation, or out of round brake drums. Other causes are
loose wheel bearings or calipers and worn or damaged tires.
NOTE: Some pedal pulsation may be felt during
ABS/EBD 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 charring of the lining. It can also generate hard spots in
rotors and drums from the overheat-cool down process. 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.
Common causes of brake drag are:
• Seized or improperly adjusted parking brake
cables
• Loose/worn wheel bearing
• Seized caliper or wheel cylinder piston
• Caliper binding on damaged or missing anti-rat-
tle clips or bushings
• Loose caliper mounting
• Drum brake shoes binding on worn/damaged
support plates
• Mis-assembled components
• Long booster output rod
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
Front brake pull condition could result from:
• Contaminated lining in one caliper
• Seized caliper piston
• Binding caliper
• Loose caliper
• Damaged anti-rattle clips
• 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 condition is where direction of pull changes after a few
stops. The cause is a combination of brake drag followed by fade at one of the brake units.
As the dragging brake overheats, efficiency is so
reduced that fade occurs. Since the opposite brake
unit is still functioning normally, its braking effect is
magnified. This causes pull to switch direction in
favor of the normally functioning brake unit.
An additional point when diagnosing a change in
pull condition concerns brake cool down. Remember
that pull will return to the original direction, if the
dragging brake unit is allowed to cool down (and is
not seriously damaged).
REAR BRAKE GRAB OR PULL
Rear grab or pull is usually caused by improperly
adjusted or seized parking brake cables, contaminated lining, bent or binding shoes and support
plates, or improperly assembled components. This is
particularly true when only one rear wheel is
involved. However, when both rear wheels are
affected, the master cylinder or proportioning valve
could be at fault.
BRAKES DO NOT HOLD AFTER DRIVING THROUGH DEEP
WATER PUDDLES
This condition is generally caused by water soaked
lining. If the lining is only wet, it can be dried by
driving with the brakes very lightly applied for a
BR/BE BRAKES - BASE 5 - 7
HYDRAULIC/MECHANICAL (Continued)
mile or two. However, if the lining is both soaked and
dirt contaminated, cleaning and/or replacement will
be necessary.
BRAKE LINING CONTAMINATION
Brake lining contamination is mostly a product of
leaking calipers or wheel cylinders, worn seals, driving through deep water puddles, or lining that has
become covered with grease and grit during repair.
Contaminated lining should be replaced to avoid further brake problems.
WHEEL AND TIRE PROBLEMS
Some conditions attributed to brake components
may actually be caused by a wheel or tire problem.
A damaged wheel can cause shudder, vibration and
pull. A worn or damaged tire can also cause pull.
Severely worn tires with very little tread left can
produce a grab-like condition as the tire loses and
recovers traction. Flat-spotted tires can cause vibration and generate shudder during brake operation. A
tire with internal damage such as a severe bruise,
cut, or ply separation can cause pull and vibration.
BRAKE NOISES
Some brake noise is common with rear drum
brakes and on some disc brakes during the first few
stops after a vehicle has been parked overnight or
stored. This is primarily due to the formation of trace
corrosion (light rust) on metal surfaces. This light
corrosion is typically cleared from the metal surfaces
after a few brake applications causing the noise to
subside.
THUMP/CLUNK NOISE
Thumping or clunk noises during braking are frequently not caused by brake components. In many
cases, such noises are caused by loose or damaged
steering, suspension, or engine components. However,
calipers that bind on the slide surfaces can generate
a thump or clunk noise. In addition, worn out,
improperly adjusted, or improperly assembled rear
brake shoes can also produce a thump noise.
STANDARD PROCEDURE
STANDARD PROCEDURE - MANUAL BLEEDING
Use Mopar brake fluid, or an equivalent quality
fluid meeting SAE J1703-F and DOT 3 standards
only. Use fresh, clean fluid from a sealed container at
all times.
(1) Remove reservoir filler caps and fill reservoir.
(2) If calipers, or wheel cylinders were overhauled,
open all caliper and wheel cylinder bleed screws.
Then close each bleed screw as fluid starts to drip
from it. Top off master cylinder reservoir once more
before proceeding.
(3) Attach one end of bleed hose to bleed screw
and insert opposite end in glass container partially
filled with brake fluid (Fig. 1). Be sure end of bleed
hose is immersed in fluid.
BRAKE SQUEAK/SQUEAL
Brake squeak or squeal may be due to linings that
are wet or contaminated with brake fluid, grease, or
oil. Glazed linings and rotors with hard spots can
also contribute to squeak. Dirt and foreign material
embedded in the brake lining will also cause squeak/
squeal.
A very loud squeak or squeal is frequently a sign of
severely worn brake lining. If the lining has worn
through to the brake shoes in spots, metal-to-metal
contact occurs. If the condition is allowed to continue,
rotors and drums can become so scored that replacement is necessary.
BRAKE CHATTER
Brake chatter is usually caused by loose or worn
components, or glazed/burnt lining. Rotors with hard
spots can also contribute to chatter. Additional causes
of chatter are out-of-tolerance rotors, brake lining not
securely attached to the shoes, loose wheel bearings
and contaminated brake lining.
Fig. 1 Bleed Hose Setup
1 - BLEED HOSE
2 - FLUID CONTAINER PARTIALLY FILLED WITH FLUID
Open up bleeder, then have a helper press down
(4)
the brake pedal. Once the pedal is down close the
bleeder. Repeat bleeding until fluid stream is clear and
free of bubbles. Then move to the next wheel.
5 - 8 BRAKES - BASE BR/BE
HYDRAULIC/MECHANICAL (Continued)
STANDARD PROCEDURE - PRESSURE
BLEEDING
Use Mopar brake fluid, or an equivalent quality
fluid meeting SAE J1703-F and DOT 3 standards
only. Use fresh, clean fluid from a sealed container at
all times.
If pressure bleeding equipment will be used, the
front brake metering valve will have to be held open
to bleed the front brakes. The valve stem is located
in the forward end or top of the combination valve.
The stem must either be pressed inward, or held outward slightly. A spring clip tool or helper is needed to
hold the valve stem in position.
Follow the manufacturers instructions carefully
when using pressure equipment. Do not exceed the
tank manufacturers pressure recommendations. Generally, a tank pressure of 15-20 psi is sufficient for
bleeding.
Fill the bleeder tank with recommended fluid and
purge air from the tank lines before bleeding.
Do not pressure bleed without a proper master cylinder adapter. The wrong adapter can lead to leakage, or drawing air back into the system. Use
adapter provided with the equipment or Adapter
6921.
BRAKE LINES
STANDARD PROCEDURE
STANDARD PROCEDURE - DOUBLE INVERTED
FLARING
A preformed metal brake tube is recommended and
preferred for all repairs. However, double-wall steel
tube can be used for emergency repair when factory
replacement parts are not readily available.
(1) Cut off damaged tube with Tubing Cutter.
(2) Ream cut edges of tubing to ensure proper
flare.
(3) Install replacement tube nut on the tube.
(4) Insert tube in flaring tool.
(5) Place gauge form over the end of the tube.
(6) Push tubing through flaring tool jaws until
tube contacts recessed notch in gauge that matches
tube diameter.
(7) Tighten the tool bar on the tube
(8) Insert plug on gauge in the tube. Then swing
compression disc over gauge and center tapered flaring screw in recess of compression disc (Fig. 2).
(9) Tighten tool handle until plug gauge is
squarely seated on jaws of flaring tool. This will start
the inverted flare.
(10) Remove the plug gauge and complete the
inverted flare.
STANDARD PROCEDURE - ISO FLARING
A preformed metal brake tube is recommended and
preferred for all repairs. However, double-wall steel
tube can be used for emergency repair when factory
replacement parts are not readily available.
To make a ISO flare use an ISO flaring tool kit.
(1) Cut off damaged tube with Tubing Cutter.
(2) Remove any burrs from the inside of the tube.
(3) Install tube nut on the tube.
(4) Position the tube in the flaring tool flush with
the top of the tool bar (Fig. 3). Then tighten the tool
bar on the tube.
(5) Install the correct size adaptor on the flaring
tool yoke screw.
(6) Lubricate the adaptor.
(7) Align the adaptor and yoke screw over the tube
(Fig. 3).
(8) Turn the yoke screw in until the adaptor is
squarely seated on the tool bar.
COMBINATION VALVE
DESCRIPTION
The combination valve/rear brake proportioning
valve are not repairable and must be replaced as an
assembly.
The pressure differential switch is connected to the
brake warning lamp.
Fig. 2 Inverted Flare Tools
BR/BE BRAKES - BASE 5 - 9
COMBINATION VALVE (Continued)
(3) Connect bleed hose to a rear wheel cylinder
and immerse hose end in container partially filled
with brake fluid.
(4) Have helper press and hold brake pedal to floor
and observe warning light.
(a) If warning light illuminates, switch is operat-
ing correctly.
(b) If light fails to illuminate, check circuit fuse,
bulb, and wiring. The parking brake switch can be
used to aid in identifying whether or not the brake
light bulb and fuse is functional. Repair or replace
parts as necessary and test differential pressure
switch operation again.
(5) If warning light still does not illuminate,
switch is faulty. Replace combination valve assembly,
bleed brake system and verify proper switch and
valve operation.
REMOVAL
(1) Remove pressure differential switch wire con-
nector (Fig. 4) from the valve.
(2) Remove the brake lines from the valve.
Fig. 3 ISO Flaring
1 - ADAPTER
2 - LUBRICATE HERE
3 - PILOT
4 - FLUSH WITH BAR
5 - TUBING
6 - BAR ASSEMBLY
(3) Remove the valve mounting bolt and remove
the valve from the bracket.
OPERATION
PRESSURE DIFFERENTIAL SWITCH
The switch is triggered by movement of the switch
valve. The purpose of the switch is to monitor fluid
pressure in the separate front/rear brake hydraulic
circuits.
A decrease or loss of fluid pressure in either
hydraulic circuit will cause the switch valve to shuttle forward or rearward in response to the pressure
differential. Movement of the switch valve will push
the switch plunger upward. This closes the switch
internal contacts completing the electrical circuit to
the warning lamp. The switch valve may remain in
an actuated position until repair restores system
pressures to normal levels.
DIAGNOSIS AND TESTING - COMBINATION
VALVE
Pressure Differential Switch
(1) Have helper sit in drivers seat to apply brake
pedal and observe red brake warning light.
(2) Raise vehicle on hoist.
Fig. 4 Pressure
1 - COMBINATION VALVE
2 - BRAKE LINES
3 - MOUNTING BOLT
4 - PRESSURE DIFFERENTIAL SWITCH
INSTALLATION
(1) Position the valve on the bracket and install
the mounting bolt. Tighten the mounting bolt to 23
N·m (210 in. lbs.).
(2) Install the brake lines into the valve and
tighten to 19-23 N·m (170-200 in. lbs.).
5 - 10 BRAKES - BASE BR/BE
COMBINATION VALVE (Continued)
(3) Connect the pressure differential switch wire
connector.
(4) Bleed base brake system, (Refer to 5 BRAKES/HYDRAULIC/MECHANICAL - STANDARD PROCEDURE).
DISC BRAKE CALIPERS
DESCRIPTION
The caliper is a one-piece casting. The piston bores
are located in the inboard side. A square-cut piston
seal is located in a machined groove in the cylinder
bore.
The caliper pistons dust boot prevents dirt, water
and road splash from entering the piston bore. The
boot is seated in a groove machined at the outer end
of the caliper piston. The boot retaining flange is
seated in a counterbore machined in the outer end of
the caliper piston bore.
Ventilated disc brake rotors are used for all applications. The rotors are serviceable and can be
machined to restore surface finish when necessary.
OPERATION
When the brakes are applied fluid pressure is
exerted against the caliper piston. The fluid pressure
is exerted equally and in all directions. This means
pressure exerted against the caliper piston and
within the caliper bore will be equal (Fig. 5).
Fluid pressure applied to the piston is transmitted
directly to the inboard brake shoe. This forces the
shoe lining against the inner surface of the disc
brake rotor. At the same time, fluid pressure within
the piston bore forces the caliper to slide inward on
the mounting bolts. This action brings the outboard
brake shoe lining into contact with the outer surface
of the disc brake rotor.
In summary, fluid pressure acting simultaneously
on both piston and caliper, produces a strong clamping action. When sufficient force is applied, friction
will attempt to stop the rotors from turning and
bring the vehicle to a stop.
Application and release of the brake pedal generates only a very slight movement of the caliper and
piston. Upon release of the pedal, the caliper and piston return to a rest position. The brake shoes do not
retract an appreciable distance from the rotor. In
fact, clearance is usually at, or close to zero. The reasons for this are to keep road debris from getting
between the rotor and lining and in wiping the rotor
surface clear each revolution.
The caliper piston seal controls the amount of piston extension needed to compensate for normal lining
wear.
1 - CALIPER
2 - PISTON
3 - PISTON BORE
4 - SEAL
5 - INBOARD SHOE
6 - OUTBOARD SHOE
During brake application, the seal is deflected outward by fluid pressure and piston movement (Fig. 6).
When the brakes (and fluid pressure) are released,
the seal relaxes and retracts the piston.
The amount of piston retraction is determined by
the amount of seal deflection. Generally the amount
is just enough to maintain contact between the piston and inboard brake shoe.
REMOVAL
REMOVAL - REAR
(1) Raise and support the vehicle.
(2) Remove the tire and wheel assembly.
(3) Compress the disc brake caliper using tool
#C4212F.
(4) Remove the caliper pin bolts.
(5) Remove the banjo bolt and discard the copper
washer.
CAUTION: Never allow the disc brake caliper to
hang from the brake hose. Damage to the brake
hose with result. Provide a suitable support to hang
the caliper securely.
(6) Remove the rear disc brake caliper (Fig. 7).
Fig. 5 Brake Caliper Operation
BR/BE BRAKES - BASE 5 - 11
DISC BRAKE CALIPERS (Continued)
Fig. 6 Lining Wear Compensation By Piston Seal
1 - PISTON
2 - CYLINDER BORE
3 - PISTON SEAL BRAKE PRESSURE OFF
4 - CALIPER HOUSING
5 - DUST BOOT
6 - PISTON SEAL BRAKE PRESSURE ON
1 - WASHERS
2 - MOUNTING BOLTS
3 - HOSE BOLT
Fig. 8 Caliper
Fig. 7 REAR CALIPER
1 - Banjo Bolt
2 - Caliper Pin Bolts
REMOVAL - FRONT
(1) Raise and support vehicle.
(2) Remove front wheel and tire assembly.
(3) Remove caliper brake hose bolt, washers and
hose (Fig. 8).
(4) Remove caliper mounting bolts.
(5) Tilt the top of the caliper up and remove it
from the adapter.
(6) Remove anti-rattle springs.
NOTE: Upper and lower anti-rattle springs are not
interchangeable.
DISASSEMBLY
(1) Drain the brake fluid from caliper.
(2) C-clamp a block of wood over one piston (Fig.
9).
Fig. 9 C-Clamp One Piston
1 - BLOCK OF WOOD
2 - C-CLAMP
3 - CALIPER
(3) Take another piece of wood and pad it with
one-inch thickness of shop towels. Place this piece in
the outboard shoe side of the caliper in front of the
other piston. This will cushion and protect caliper
piston during removal (Fig. 10).
(4) To remove the caliper piston direct short
bursts of low pressure air with a blow gun
through the caliper brake hose port. Use only enough
air pressure to ease the piston out.
5 - 12 BRAKES - BASE BR/BE
DISC BRAKE CALIPERS (Continued)
Fig. 10 Protect Caliper Piston
1 - CALIPER
2 - PADDED BLOCK OF WOOD
3 - C-CLAMP
CAUTION: Do not blow the piston out of the bore
with sustained air pressure. This could result in a
cracked piston.
WARNING: NEVER ATTEMPT TO CATCH THE PISTON AS IT LEAVES THE BORE. THIS COULD
RESULT IN PERSONAL INJURY.
(5) Remove the C-clamp and block of wood from
the caliper and clamp it over the dust boot of the
first piston removed. This will seal the empty piston
bore.
(6) Move the padded piece of wood in front of the
other piston.
(7) Remove the second piston using the same procedure with short bursts of low pressure air.
(8) Remove piston dust boots with a suitable pry
tool (Fig. 11).
(9) Remove piston seals from caliper (Fig. 12).
Fig. 11 Piston Dust Boot Removal
1 - CALIPER
2 - DUST BOOT
Fig. 12 Piston Seal
1 - CALIPER
2 - PISTON BORE
3 - PISTON SEAL
CAUTION: Do not scratch piston bore while removing the seals.
(10) Push caliper mounting bolt bushings out of
the boot seals and remove the boot seals from the
caliper (Fig. 13).
(11) Remove caliper bleed screw.
CLEANING
Clean the caliper components with clean brake
fluid or brake clean only. Wipe the caliper and piston
dry with lint free towels or use low pressure compressed air.
CAUTION: Do not use gasoline, kerosene, thinner,
or similar solvents. These products may leave a
residue that could damage the piston and seal.
INSPECTION
The piston is made from a phenolic resin (plastic
material) and should be smooth and clean.
The piston must be replaced if cracked or scored.
Do not attempt to restore a scored piston surface by
sanding or polishing.
BR/BE BRAKES - BASE 5 - 13
DISC BRAKE CALIPERS (Continued)
ASSEMBLY
CAUTION: Dirt, oil, and solvents can damage caliper seals. Insure assembly area is clean and dry.
(1) Lubricate caliper pistons, piston seals and piston bores with clean, fresh brake fluid.
(2) Install new piston seals into caliper bores (Fig.
15).
NOTE: Verify seal is fully seated and not twisted.
Fig. 13 Bushings And Boot Seals
1 - CALIPER
2 - BUSHING
3 - BOOT SEAL
CAUTION: If the caliper piston is replaced, install
the same type of piston in the caliper. Never interchange phenolic resin and steel caliper pistons.
The pistons, seals, seal grooves, caliper bore and
piston tolerances are different.
The bore can be lightly polished with a brake
hone to remove very minor surface imperfections
(Fig. 14). The caliper should be replaced if the bore is
severely corroded, rusted, scored, or if polishing
would increase bore diameter more than 0.025 mm
(0.001 inch).
Fig. 14 Polishing Piston Bore
1 - HONE
2 - CALIPER
3 - PISTON BORE
Fig. 15 Piston Seal
1 - CALIPER
2 - PISTON BORE
3 - PISTON SEAL
(3) Lightly lubricate lip of new boot with silicone
grease. Install boot on piston and work boot lip into
the groove at the top of piston.
(4) Stretch boot rearward to straighten boot folds,
then move boot forward until folds snap into place.
(5) Install piston into caliper bore and press piston
down to the bottom of the caliper bore by hand or
with hammer handle (Fig. 16).
(6) Seat dust boot in caliper (Fig. 17) with Handle
C-4171 and Installer:
• HD 56 mm caliper: Installer C-4340
• LD 54 mm caliper: Installer C-3716-A
(7) Install the second piston and dust boot.
(8) Lubricate caliper mounting bolt bushings, boot
seals and bores with Mopar brake grease or Dow
Corningt 807 grease only.
CAUTION: Use of alternative grease may cause
damage to the boots seals.
(9) Install the boot seals into the caliper seal bores
and center the seals in the bores.
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