2002 DODGE RAM warning

INSTALLATION
NOTE: If master cylinder is replaced, bleed cylinder
before installation.
(1) Install master cylinder on the booster mount-
ing studs.
(2) Install mounting nuts and tighten to 23 N´m
(17 ft. lbs.).
(3) Install brake lines and tighten to 19-23 N´m
(170-200 in. lbs.).
(4) Bleed base brake system, (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL - STAN-
DARD PROCEDURE)
PARKING BRAKE
DESCRIPTION
The parking brakes are operated by a system of
cables and levers attached to a primary and second-
ary shoe positioned within the drum section of the
rotor.
The drum-in-hat design utilizes an independent set
of shoes to park the vehicle (Fig. 51).
OPERATION
To apply the parking brake the pedal is depressed.
This creates tension in the cable which pulls forward
on the park brake lever. The lever pushes the park
brake shoes outward and into contact with the drum
section of the rotor. The contact of shoe to rotor parks
the vehicle.A torsion locking mechanism is used to hold the
pedal in an applied position. Parking brake release is
accomplished by the hand release.
A parking brake switch is mounted on the parking
brake lever and is actuated by movement of the
lever. The switch, which is in circuit with the red
warning light in the dash, will illuminate the warn-
ing light whenever the parking brake is applied.
Parking brake adjustment is controlled by a cable
tensioner mechanism. The cable tensioner, once
adjusted at the factory, should not need further
adjustment under normal circumstances. Adjustment
may be required if a new tensioner, or cables are
installed, or disconnected.
PEDAL
REMOVAL
(1) Release the parking brake.
(2) Raise the vehicle.
(3) Loosen the cable tensioner nut at the equalizer
to create slack in the front cable.
(4) Lower the vehicle.
(5) Remove the knee bolster, (Refer to 23 - BODY/
INSTRUMENT PANEL/STEERING COLUMN
OPENING COVER - REMOVAL).
(6) Disconnect the brake lamp wire from the
switch on the pedal assembly.
(7) Roll the carpet back, loosen the front cable
grommet from the floorpan and the cable retainer.
(8) Disengage the cable end connector (Fig. 52)
from the arm on the pedal assembly.
Fig. 50 Master Cylinder
1 - MOUNTING NUT
2 - MOUNTING NUT
3 - BRAKE LINES
4 - MASTER CYLINDER
Fig. 51 SHOES REMOVAL
1 - PARK BRAKE SHOES
2 - ADJUSTER
3 - RETURN SPRINGS
4 - SPLASH SHIELD
5 - HOLD DOWNS
5 - 28 BRAKES - BASEBR/BE
MASTER CYLINDER (Continued)

BRAKES - ABS
TABLE OF CONTENTS
page page
BRAKES - ABS
DESCRIPTION.........................35
OPERATION...........................36
DIAGNOSIS AND TESTING - ANTILOCK
BRAKES............................36
STANDARD PROCEDURE
STANDARD PROCEDURE - RWAL SERVICE
PRECAUTIONS.......................36
STANDARD PROCEDURE - BLEEDING ABS
BRAKE SYSTEM......................36
SPECIFICATIONS
TORQUE CHART......................37
FRONT WHEEL SPEED SENSOR
DESCRIPTION.........................38
OPERATION...........................38
REMOVAL
REMOVAL - 4X2......................39REMOVAL - 4X4......................39
INSTALLATION
INSTALLATION - 4X2...................39
INSTALLATION - 4X4...................39
REAR WHEEL SPEED SENSOR
DIAGNOSIS AND TESTING - REAR WHEEL
SPEED SENSOR......................40
REMOVAL.............................40
INSTALLATION.........................40
HCU (HYDRAULIC CONTROL UNIT)
DESCRIPTION.........................40
OPERATION...........................40
REMOVAL.............................41
INSTALLATION.........................41
BRAKES - ABS
DESCRIPTION
The antilock brake system (ABS) is an electroni-
cally operated, all wheel brake control system. 2500
and 3500 vehicles have Electronic Brake Distribution
(EBD) designed into the systen which eliminates the
combination/proportioning valve.
The system is designed to prevent wheel lockup
and maintain steering control during periods of high
wheel slip when braking. Preventing lockup is accom-
plished by modulating fluid pressure to the wheel
brake units.
The hydraulic system is a three channel design.
The front wheel brakes are controlled individually
and the rear wheel brakes in tandem (Fig. 1). The
ABS electrical system is separate from other electri-
cal circuits in the vehicle. A specially programmed
controller antilock brake unit operates the system
components.
ABS system major components include:
²Controller Antilock Brakes (CAB)
²Hydraulic Control Unit (HCU)
²Wheel Speed Sensors (WSS)²ABS Warning Light
Fig. 1 Antilock Brake System
1 - MASTER CYLINDER AND RESERVOIR
2 - POWER BRAKE BOOSTER
3 - WIRES TO WHEEL SPEED SENSORS
4 - RIGHT REAR WHEEL
5 - LEFT REAR WHEEL
6 - HYDRAULIC BRAKE LINES TO WHEELS
7 - COMBINATION VALVE
8 - HARNESS
9 - RIGHT FRONT WHEEL
10 - LEFT FRONT WHEEL
11 - CAB/HCU
BR/BEBRAKES - ABS 5 - 35

OPERATION
Battery voltage is supplied to the CAB when a
speed of 15 miles per hour is reached. The CAB per-
forms a system initialization procedure at this point.
Initialization consists of a static and dynamic self
check of system electrical components.
The static and dynamic checks occurs at ignition
start up. During the dynamic check, the CAB briefly
cycles the pump and solenoids to verify operation. An
audible noise may be heard during this self check.
This noise should be considered normal.
If an ABS component exhibits a fault during ini-
tialization, the CAB illuminates the amber warning
light and registers a fault code in the microprocessor
memory.
The CAB monitors wheel speed sensor inputs con-
tinuously while the vehicle is in motion. However,
the CAB will not activate any ABS components as
long as sensor inputs indicate normal braking.
During normal braking, the master cylinder, power
booster and wheel brake units all function as they
would in a vehicle without ABS. The HCU compo-
nents are not activated.
The purpose of the antilock system is to prevent
wheel lockup during periods of high wheel slip. Pre-
venting lockup helps maintain vehicle braking action
and steering control.
The antilock CAB activates the system whenever
sensor signals indicate periods of wheel slip. Periods
of wheel slip occur when brake stops involve high
pedal pressure and rate of vehicle deceleration.
The antilock system prevents lockup during a
wheel slip condition by modulating fluid apply pres-
sure to the wheel brake units.
Brake fluid apply pressure is modulated according
to wheel speed, degree of slip and rate of decelera-
tion. Sensors at each front wheel convert wheel speed
into electrical signals. These signals are transmitted
to the CAB for processing and determination of
wheel slip and deceleration rate.
The ABS system has three fluid pressure control
channels. The front brakes are controlled separately
and the rear brakes in tandem. A speed sensor input
signal indicating a wheel slip condition activates the
CAB antilock program.
There are Two solenoid valves (Isolation and Dump
valve) which are used in each antilock control chan-
nel. The valves are all located within the HCU valve
body and work in pairs to either increase, hold, or
decrease apply pressure as needed in the individual
control channels.
During an ABS stop the ISO valve actuates, Stop-
ping anymore pressure build Ðup to the calipers.
Then the Dump valve dumps off pressure until the
wheel unlocks. This will continue until the wheels
quit slipping altogether.
DIAGNOSIS AND TESTING - ANTILOCK
BRAKES
The ABS brake system performs several self-tests
every time the ignition switch is turned on and the
vehicle is driven. The CAB monitors the systems
input and output circuits to verify the system is oper-
ating correctly. If the on board diagnostic system
senses that a circuit is malfunctioning the system
will set a trouble code in its memory.
NOTE: An audible noise may be heard during the
self-test. This noise should be considered normal.
NOTE: The MDS or DRB III scan tool is used to
diagnose the ABS system. For additional informa-
tion refer to the Antilock Brake section in Group
8W. For test procedures refer to the Chassis Diag-
nostic Manual.
STANDARD PROCEDURE
STANDARD PROCEDURE - RWAL SERVICE
PRECAUTIONS
The RWAL 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.In testing for open or short circuits, do
not ground or apply voltage to any of the cir-
cuits unless instructed to do so for a diagnostic
procedure.These circuits should only be tested
using a high impedance multi-meter or the DRB
tester 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: Use only factory wiring harnesses. Do
not cut or splice wiring to the brake circuits. The
addition of after-market electrical equipment (car
phone, radar detector, citizen band radio, trailer
lighting, trailer brakes, ect.) on a vehicle equipped
with antilock brakes may affect the function of the
antilock brake system.
STANDARD PROCEDURE - BLEEDING ABS
BRAKE SYSTEM
ABS system bleeding requires conventional bleed-
ing methods plus use of the DRB scan tool. The pro-
cedure involves performing a base brake bleeding,
followed by use of the scan tool to cycle and bleed the
5 - 36 BRAKES - ABSBR/BE
BRAKES - ABS (Continued)

NOTE: Check the sensor wire routing. Be sure the
wire is clear of all chassis components and is not
twisted or kinked at any spot.
(6) Install the tire and wheel assembly.
(7) Remove the support and lower the vehicle.
(8) Reconnect the ABS wheel speed sensor wire
electrical connector inside the engine compartment.
(9) Apply the brakes several times to seat the
brake shoes and caliper piston. Do not move the vehi-
cle until a firm brake pedal is obtained.
(10) Verify the wheel speed sensor operation with
a scan tool.
REAR WHEEL SPEED SENSOR
DIAGNOSIS AND TESTING - REAR WHEEL
SPEED SENSOR
Diagnosis of base brake conditions which are
mechanical in nature should be performed first. This
includes brake noise, lack of power assist, parking
brake, or vehicle vibration during normal braking.
The Antilock brake system performs several self-
tests every time the ignition switch is turned on and
the vehicle is driven. The CAB monitors the system
inputs and outputs circuits to verify the system is
operating properly. If the CAB senses a malfunction
in the system it will set a DTC into memory and trig-
ger the warning lamp.
NOTE: The MDS or DRB III scan tool is used to
diagnose the Antilock Brake system. For test proce-
dures refer to the Chassis Diagnostic Manual.
REMOVAL
(1) Raise vehicle on hoist.
(2) Remove brake line mounting nut and remove
the brake line from the sensor stud.
(3) Remove mounting stud from the sensor and
shield (Fig. 6) .
(4) Remove sensor and shield from differential
housing.
(5) Disconnect sensor wire harness and remove
sensor.
INSTALLATION
(1) Connect harness to sensor.Be sure seal is
securely in place between sensor and wiring
connector.
(2) Install O-ring on sensor (if removed).
(3) Insert sensor in differential housing.
(4) Install sensor shield.
(5) Install the sensor mounting stud and tighten to
24 N´m (18 ft. lbs.).(6) Install the brake line on the sensor stud and
install the nut.
(7) Lower vehicle.
HCU (HYDRAULIC CONTROL
UNIT)
DESCRIPTION
The hydraulic control unit (HCU) consists of a
valve body, pump, two accumulators and a motor.
The assembly is mounted on the driverside inner
fender under the hood.
OPERATION
The pump, motor, and accumulators are combined
into an assembly attached to the valve body. The
accumulators store the extra fluid which had to be
dumped from the brakes. This is done to prevent the
wheels from locking up. The pump provides the fluid
volume needed and is operated by a DC type motor.
The motor is controlled by the CAB.
During normal braking, the HCU solenoid valves
and pump are not activated. The master cylinder and
power booster operate the same as a vehicle without
an ABS brake system.
The valve body contains the solenoid valves. The
valves modulate brake pressure during antilock brak-
ing and are controlled by the CAB.
The HCU provides three channel pressure control
to the front and rear brakes. One channel controls
the rear wheel brakes in tandem. The two remaining
channels control the front wheel brakes individually.
Fig. 6 Rear Speed Sensor Mounting
1 - WHEEL SPEED SENSOR
2 - AXLE
5 - 40 BRAKES - ABSBR/BE
FRONT WHEEL SPEED SENSOR (Continued)

CLUTCH
TABLE OF CONTENTS
page page
CLUTCH
DESCRIPTION..........................1
OPERATION............................2
WARNING.............................2
DIAGNOSIS AND TESTING - CLUTCH........2
SPECIFICATIONS - CLUTCH...............7
CLUTCH DISC
REMOVAL.............................7
INSTALLATION..........................8
CLUTCH HOUSING
DIAGNOSIS AND TESTING - CLUTCH
HOUSING............................9
REMOVAL.............................11
INSTALLATION.........................11
CLUTCH RELEASE BEARING
REMOVAL.............................12
INSTALLATION.........................12FLYWHEEL
DIAGNOSIS AND TESTING - FLYWHEEL.....13
DISASSEMBLY.........................13
ASSEMBLY............................14
PILOT BEARING
REMOVAL.............................14
INSTALLATION.........................14
CLUTCH PEDAL
REMOVAL.............................15
INSTALLATION.........................15
LINKAGE
REMOVAL.............................15
INSTALLATION.........................16
CLUTCH PEDAL POSITION SWITCH
DESCRIPTION.........................17
OPERATION...........................17
CLUTCH
DESCRIPTION
The clutch mechanism consists of a flywheel, dry-
type disc, diaphragm style pressure plate (Fig. 1) and
hydraulic linkage. The flywheel is bolted to the rear
flange of the crankshaft. The clutch pressure plate is
bolted to the flywheel with the clutch disc between
these two components. The clutch system provides
the mechanical, link between the engine and the
transmission. The system is designed to transfer the
torque output of the engine, to the transmission
while isolating the transmission from the engine fir-
ing pulses to minimize concerns such as gear rattle.
Fig. 1 ENGINE POWERFLOW
BR/BECLUTCH 6 - 1

OPERATION
When the clutch pedal is depressed, it actuates the
clutch master cylinder. This sends hydraulic pressure
to the clutch slave cylinder. The release fork is then
actuated by the slave cylinder mounted on the trans-
mission housing. The release fork pivots on a ball
stud mounted in the transmission housing and
pushes the release bearing. The release bearing then
depresses the pressure plate spring fingers, thereby
releasing pressure on the clutch disc and allowing
the engine crankshaft to spin independently of the
transmission input shaft (Fig. 2).
WARNING
WARNING: EXERCISE CARE WHEN SERVICING
CLUTCH COMPONENTS. FACTORY INSTALLED
CLUTCH DISCS DO NOT CONTAIN ASBESTOS
FIBERS. DUST AND DIRT ON CLUTCH PARTS MAY
CONTAIN ASBESTOS FIBERS FROM AFTERMAR-
KET COMPONENTS. BREATHING EXCESSIVE CON-
CENTRATIONS OF THESE FIBERS CAN CAUSE
SERIOUS BODILY HARM. WEAR A RESPIRATOR
DURING SERVICE AND NEVER CLEAN CLUTCH
COMPONENTS WITH COMPRESSED AIR OR WITH
A DRY BRUSH. EITHER CLEAN THE COMPONENTSWITH A WATER DAMPENED RAGS OR USE A VAC-
UUM CLEANER SPECIFICALLY DESIGNED FOR
REMOVING ASBESTOS FIBERS AND DUST. DO NOT
CREATE DUST BY SANDING A CLUTCH DISC.
REPLACE THE DISC IF THE FRICTION MATERIAL IS
DAMAGED OR CONTAMINATED. DISPOSE OF ALL
DUST AND DIRT CONTAINING ASBESTOS FIBERS
IN SEALED BAGS OR CONTAINERS. THIS WILL
HELP MINIMIZE EXPOSURE TO YOURSELF AND TO
OTHERS. FOLLOW ALL RECOMMENDED SAFETY
PRACTICES PRESCRIBED BY THE OCCUPATIONAL
SAFETY AND HEALTH ADMINISTRATION (OSHA)
AND THE ENVIRONMENTAL SAFETY AGENCY
(EPA), FOR THE HANDLING AND DISPOSAL OF
PRODUCTS CONTAINING ASBESTOS.
DIAGNOSIS AND TESTING - CLUTCH
A road test and component inspection (Fig. 3) is
recommended to determine a clutch problem.
During a road test, drive the vehicle at normal
speeds. Shift the transmission through all gear
ranges and observe clutch action. If the clutch chat-
ters, grabs, slips or does not release properly, remove
and inspect the clutch components. If the problem is
noise or hard shifting, further diagnosis may be
needed as the transmission or another driveline com-
ponent may be at fault.
CLUTCH CONTAMINATION
Fluid contamination is a frequent cause of clutch
malfunctions. Oil, water or clutch fluid on the clutch
disc and pressure plate surfaces will cause chatter,
slip and grab.
During inspection, note if any components are con-
taminated with oil, hydraulic fluid or water/road
splash.
Oil contamination indicates a leak at either the
rear main seal or transmission input shaft. Oil leak-
age produces a residue of oil on the housing interior
and on the clutch cover and flywheel. Heat buildup
caused by slippage between the cover, disc and fly-
wheel, can sometimes bake the oil residue onto the
components. The glaze-like residue ranges in color
from amber to black.
Road splash contamination means dirt/water is
entering the clutch housing due to loose bolts, hous-
ing cracks or through hydraulic line openings. Driv-
ing through deep water puddles can force water/road
splash into the housing through such openings.
Clutch fluid leaks are usually from damaged slave
cylinder push rod seals.
Fig. 2 CLUTCH OPERATION
1 - FLYWHEEL
2 - PRESSURE PLATE FINGERS
3 - PIVOT POINT
4 - RELEASE BEARING PUSHED IN
5 - CLUTCH DISC ENGAGED
6 - CLUTCH DISC ENGAGED
7 - RELEASE BEARING
6 - 2 CLUTCHBR/BE
CLUTCH (Continued)

(2) Install release fork and release bearing (Fig.
21) and verify fork and bearing are secured by spring
clips. Also be sure that the release fork is installed
properly.
NOTE: The rear side of the release lever has one
end with a raised area. This raised area goes
toward the slave cylinder side of the transmission.
(3) Install clutch housing, if removed.(4) Install transmission and transfer case, if
equipped. Refer to 21 Transmission and Transfer
Case for procedures.
FLYWHEEL
DIAGNOSIS AND TESTING - FLYWHEEL
Check flywheel runout whenever misalignment is
suspected. Flywheel runout should not exceed 0.08
mm (0.003 in.). Measure runout at the outer edge of
the flywheel face with a dial indicator. Mount the
indicator on a stud installed in place of one of the fly-
wheel bolts.
Common causes of runout are:
²heat warpage
²improper machining
²incorrect bolt tightening
²improper seating on crankshaft flange shoulder
²foreign material on crankshaft flange
Flywheel machining is not recommended. The fly-
wheel clutch surface is machined to a unique contour
and machining will negate this feature. Minor fly-
wheel scoring can be cleaned up by hand with 180
grit emery or with surface grinding equipment.
Remove only enough material to reduce scoring
(approximately 0.001 - 0.003 in.). Heavy stock
removal isnot recommended.Replace the flywheel
if scoring is severe and deeper than 0.076 mm (0.003
in.). Excessive stock removal can result in flywheel
cracking or warpage after installation; it can also
weaken the flywheel and interfere with proper clutch
release.
Clean the crankshaft flange before mounting the
flywheel. Dirt and grease on the flange surface may
cock the flywheel causing excessive runout. Use new
bolts when remounting a flywheel and secure the
bolts with Mopar Lock And Seal or equivalent.
Tighten flywheel bolts to specified torque only. Over-
tightening can distort the flywheel hub causing
runout.
DISASSEMBLY
NOTE: If the teeth are worn or damaged, the fly-
wheel should be replaced as an assembly. This is
the recommended repair. In cases where a new fly-
wheel is not readily available, (V10/Diesel Engine
only) a replacement ring gear can be installed. The
following procedure must be observed to avoid
damaging the flywheel and replacement gear.
WARNING: WEAR PROTECTIVE GOGGLES OR
SAFETY GLASSES WHILE CUTTING RING GEAR.
Fig. 20 Clutch Release Components
1 - CONED WASHER
2 - CLUTCH HOUSING
3 - RELEASE FORK
4 - RELEASE BEARING AND SLEEVE
5 - PIVOT 23 N´m (200 IN. LBS.)
6 - SPRING
Fig. 21 Clutch Release Fork
1 - PIVOT BALL
2 - FORK
3 - SLAVE CYLINDER OPENING
4 - BEARING
BR/BECLUTCH 6 - 13
CLUTCH RELEASE BEARING (Continued)

(1) Mark position of the old gear for alignment ref-
erence on the flywheel. Use a scriber for this pur-
pose.
(2) Remove the old gear by cutting most of the way
through it (at one point) with an abrasive cut-off
wheel. Then complete removal with a cold chisel or
punch.
ASSEMBLY
NOTE: The ring gear is a shrink fit on the flywheel.
This means the gear must be expanded by heating
in order to install it. The method of heating and
expanding the gear is extremely important. Every
surface of the gear must be heated at the same
time to produce uniform expansion. An oven or
similar enclosed heating device must be used. Tem-
perature required for uniform expansion is approxi-
mately 375É F.
CAUTION: Do not use an oxy/acetylene torch to
remove the old gear, or to heat and expand a new
gear. The high temperature of the torch flame can
cause localized heating that will damage the fly-
wheel. In addition, using the torch to heat a replace-
ment gear will cause uneven heating and
expansion. The torch flame can also anneal the
gear teeth resulting in rapid wear and damage after
installation.
WARNING: WEAR PROTECTIVE GOGGLES OR
SAFETY GLASSES AND HEAT RESISTENT GLOVES
WHEN HANDLING A HEATED RING GEAR.
(1) The heated gear must be installed evenly to
avoid misalignment or distortion.
(2) Position and install the heated ring gear on the
flywheel with a shop press and a suitable press
plates.
(3) Place flywheel on work bench and let it cool in
normal shop air. Allow the ring gear to cool down
completely before installation it on the engine.
CAUTION: Do not use water or compressed air to
cool the flywheel. The rapid cooling produced by
water or compressed air will distort or crack the
new gear.
PILOT BEARING
REMOVAL
(1) Remove transmission, transfer case, if
equipped and clutch housing. Refer to 21 Transmis-
sion and Transfer Case for procedures.
(2) Remove pressure plate and disc.
(3) Using a suitable blind hole puller to remove
pilot bearing.
INSTALLATION
(1) Clean bearing bore with solvent and wipe dry
with shop towel.
(2) Install new bearing with clutch alignment tool
(Fig. 22). Keep bearing straight and tap bearing into
place until flush with edge of bearing bore. Do not
recess bearing.
(3) Install clutch cover and disc.
(4) Install clutch housing, transmission and trans-
fer case, if equipped. Refer to 21 Transmission and
Transfer Case for procedures.
Fig. 22 Installing Pilot Bearing
1 - PILOT BEARING
2 - ALIGNMENT TOOL
3 - LETTER SIDE MUST FACE TRANSMISSION
6 - 14 CLUTCHBR/BE
FLYWHEEL (Continued)