2003 DODGE RAM warning

A towed vehicle should be raised until lifted wheels
are a minimum 100 mm (4 in) from the ground. Be
sure there is adequate ground clearance at the oppo-
site end of the vehicle, especially when towing over
rough terrain or steep rises in the road. If necessary,
remove the wheels from the lifted end of the vehicle
and lower the vehicle closer to the ground, to
increase the ground clearance at the opposite end of
the vehicle. Install lug nuts on wheel attaching studs
to retain brake drums or rotors.
RAMP ANGLE
If a vehicle with flat-bed towing equipment is used,
the approach ramp angle should not exceed 15
degrees.
TOWING WHEN KEYS ARE NOT AVAILABLE
When the vehicle is locked and keys are not avail-
able, use a flat bed hauler. A Wheel-lift or Sling-type
device can be used on 4WD vehicles providedall the
wheels are lifted off the ground using tow dol-
lies.
FOUR-WHEEL-DRIVE VEHICLE TOWING
Chrysler Corporation recommends that a vehicle be
transported on a flat-bed device. A Wheel-lift or
Sling-type device can be used providedall the
wheels are lifted off the ground using tow dol-
lies.
WARNING: WHEN TOWING A DISABLED VEHICLE
AND THE DRIVE WHEELS ARE SECURED IN A
WHEEL LIFT OR TOW DOLLIES, ENSURE THE
TRANSMISSION IS IN THE PARK POSITION (AUTO-
MATIC TRANSMISSION) OR A FORWARD DRIVE
GEAR (MANUAL TRANSMISSION).
CAUTION: Many vehicles are equipped with air
dams, spoilers, and/or ground effect panels. To
avoid component damage, a wheel-lift towing vehi-
cle or a flat-bed hauling vehicle is recommended.
0 - 16 LUBRICATION & MAINTENANCEDR
TOWING (Continued)

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 PIS-
TON 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 pro-
cedure withshort bursts of low pressure air.
(8) Remove piston dust boots with a suitable pry
tool (Fig. 23).
(9) Remove piston seals from caliper (Fig. 24).
CAUTION: Do not scratch piston bore while remov-
ing the seals.
(10) Push caliper mounting bolt bushings out of
the boot seals and remove the boot seals from the
caliper (Fig. 25).
(11) Remove caliper bleed screw.
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.CAUTION: If the caliper piston is replaced, install
the same type of piston in the caliper. Never inter-
change phenolic resin and steel caliper pistons.
The pistons, seals, seal grooves, caliper bore and
piston tolerances are different.
The bore can belightlypolished with a brake
hone to remove very minor surface imperfections
(Fig. 26). 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. 22 Protect Caliper Piston
1 - CALIPER
2 - PADDED BLOCK OF WOOD
3 - C-CLAMP
Fig. 23 Piston Dust Boot Removal
1 - CALIPER
2 - DUST BOOT
Fig. 24 Piston Seal
1 - CALIPER
2 - PISTON BORE
3 - PISTON SEAL
5 - 14 BRAKES - BASEDR
DISC BRAKE CALIPERS (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
Brakes Self Apply 1. Dump valve faulty. 1. Replace booster.
2. Contamination in hydraulic
system.2. Flush hydraulic system and replace
booster.
3. Restriction in booster return hose. 3. Replace hose.
Booster Chatter, Pedal
Vibration1. Slipping pump belt. 1. Replace power steering belt.
2. Low pump fluid level. 2. Fill pump and check for leaks.
Grabbing Brakes 1. Low pump flow. 1. Test and repair/replace pump.
2. Faulty spool valve action. 2. Replace booster.
STANDARD PROCEDURE - BLEEDING
The hydraulic booster is generally self-bleeding,
this procedure will normally bleed the air from the
booster. Normal driving and operation of the unit will
remove any remaining trapped air.
(1) Fill power steering pump reservoir.
(2) Disconnect fuel shutdown relay and crank the
engine for several seconds, Refer to Fuel System for
relay location and WARNING.
(3) Check fluid level and add if necessary.
(4) Connect fuel shutdown relay and start the
engine.
(5) Turn the steering wheel slowly from lock to
lock twice.
(6) Stop the engine and discharge the accumulator
by depressing the brake pedal 5 times.
(7) Start the engine and turn the steering wheel
slowly from lock to lock twice.
(8) Turn off the engine and check fluid level and
add if necessary.
NOTE: If fluid foaming occurs, wait for foam to dis-
sipate and repeat steps 7 and 8.
REMOVAL
NOTE: If the booster is being replaced because the
power steering fluid is contaminated, flush the
power steering system before replacing the booster.
(1) With engine off depress the brake pedal 5
times to discharge the accumulator.
(2) Remove brake lines from master cylinder.
(3) Remove mounting nuts from the master cylin-
der.
(4) Remove the bracket from the hydraulic booster
lines and master cylinder mounting studs.
(5) Remove the master cylinder.
(6) Remove the return hose and the two pressure
lines from the hydraulic booster (Fig. 49).(7) Remove the booster push rod clip, washer and
rod remove from the brake pedal.
(8) Remove the mounting nuts from the hydraulic
booster and remove the booster.INSTALLATION
(1) Install the hydraulic booster and tighten the
mounting nuts to 28 N´m (21 ft. lbs.).
(2) Install the booster push rod, washer and clip
onto the brake pedal.
(3) Install the master cylinder on the mounting
studs. and tighten the mounting nuts to 23 N´m (17
ft. lbs.).
(4) Install the brake lines to the master cylinder
and tighten to 19-200 N´m (170-200 in. lbs.).
(5) Install the hydraulic booster line bracket onto
the master cylinder mounting studs.
(6) Install the master cylinder mounting nuts and
tighten to 23 N´m (17 ft. lbs.).
Fig. 49 HYDRO-BOOST UNIT
1 - INLET HOSE
2 - HYDRO-BOOST UNIT
3 - MASTER CYLINDER UNIT
4 - RETURN HOSE
5 - OUTLET HOSE
DRBRAKES - BASE 5 - 27
HYDRO-BOOST BRAKE BOOSTER (Continued)

(6) Install the rotor (Refer to 5 - BRAKES/HY-
DRAULIC/MECHANICAL/ROTORS - INSTALLA-
TION).
(7) Install the caliper adapter (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/DISC
BRAKE CALIPER ADAPTER - INSTALLATION).
(8) Install the caliper (Refer to 5 - BRAKES/HY-
DRAULIC/MECHANICAL/DISC BRAKE CALIPERS
- INSTALLATION).
(9) Install the wheel and tire assembly (Refer to 22
- TIRES/WHEELS/WHEELS - STANDARD PROCE-
DURE).
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. 56).
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.
Fig. 54 SUPPORT PLATE
1 - SUPPORT PLATE
2 - MOUNTING STUDS
Fig. 55 SUPPORT PLATE WITH BRAKES MOUNTED
1 - SUPPORT PLATE
2 - MOUNTING NUTS
Fig. 56 SUPPORT PLATE WITH BRAKES MOUNTED
1 - SUPPORT PLATE
2 - MOUNTING NUTS
5 - 30 BRAKES - BASEDR
SUPPORT PLATE (Continued)

BRAKES - ABS
TABLE OF CONTENTS
page page
BRAKES - ABS
DESCRIPTION.........................39
OPERATION...........................39
STANDARD PROCEDURE - ABS BRAKE
BLEEDING...........................40
SPECIFICATIONS
TORQUE CHART......................40
FRONT WHEEL SPEED SENSOR
DESCRIPTION.........................41
OPERATION...........................41
REMOVAL.............................41
INSTALLATION.........................42
REAR WHEEL SPEED SENSOR
DIAGNOSIS AND TESTING - REAR WHEEL
ANTILOCK...........................42
REMOVAL.............................42
INSTALLATION.........................43
TONE WHEEL
DIAGNOSIS AND TESTING - REAR WHEEL
SPEED SENSOR......................43HYDRAULIC/MECHANICAL
DESCRIPTION - ELECTRONIC VARIABLE
BRAKE PROPORTIONING...............43
OPERATION - ELECTRONIC VARIABLE
BRAKE PROPORTIONING...............43
HCU (HYDRAULIC CONTROL UNIT)
DESCRIPTION.........................43
OPERATION...........................43
REMOVAL.............................44
INSTALLATION.........................44
R WA L VA LV E
DESCRIPTION.........................44
OPERATION...........................44
REMOVAL.............................45
INSTALLATION.........................45
BRAKES - ABS
DESCRIPTION
The antilock brake system (ABS) is an electroni-
cally operated, three channel brake control system.
The vehicle has Electronic Variable Brake Propor-
tioning (EVBP) designed into the system which elim-
inates the combination/proportioning valve.
The system is designed to prevent wheel lockup
and maintain steering control during braking. Pre-
venting lockup is accomplished 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. The ABS elec-
trical system is separate from other electrical 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
OPERATION
Battery voltage is supplied to the CAB. The CAB
performs a system initialization procedure at start
up. A check of the ABS motor is performed at 15
miles per hour. 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 solenoids to verify operation. An audible noise
may be heard during this self check. This noise
should be considered normal. The ABS motor and
pump are then checked at a speed of 15 mile per
hour.
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.
DRBRAKES - ABS 5 - 39

(3) Remove the wheel speed sensor from the hub.
(4) Remove the wiring from the clips and discon-
nect the electrical connector.
INSTALLATION
(1) Install the wiring to the clips and Reconnect
the electrical connector.
(2) Install the wheel speed sensor to the hub.
(3) Install the wheel speed sensor mounting bolt to
the hub. Tighten the bolt to 21 N´m (190 in. lbs.).
(4) Install the front rotor and brake caliper assem-
bly (Refer to 5 - BRAKES/HYDRAULIC/MECHANI-
CAL/ROTORS - INSTALLATION).
REAR WHEEL SPEED SENSOR
DIAGNOSIS AND TESTING - REAR WHEEL
ANTILOCK
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 RWAL 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 RWAL system. For test procedures
refer to the Chassis Diagnostic Manual.
REMOVAL
(1) Raise the vehicle on a hoist.
(2) Remove the brake line mounting nut and
remove the brake line from the sensor stud.
(3) Remove the mounting stud from the sensor and
shield (Fig. 4).
(4) Remove the sensor and shield from the differ-
ential housing.
(5) Disconnect the sensor wire harness and remove
the sensor.
Fig. 2 Data Link Connector - Typical
1 - 16±WAY DATA LINK CONNECTOR
Fig. 3 WHEEL SPEED SENSOR
1 - WHEEL SPEED SENSOR MOUNTING BOLT
2 - WHEEL SPEED SENSOR
3 - HUB/BEARING
Fig. 4 REAR WHEEL SPEED SENSOR
1 - WHEEL SPEED SENSOR
2 - MOUNTING BOLT
3 - AXLE HOUSING
5 - 42 BRAKES - ABSDR
FRONT WHEEL SPEED SENSOR (Continued)

INSTALLATION
(1) Connect the harness to the sensor.Be sure
the seal is securely in place between the sensor
and the wiring connector.
(2) Install the O-ring on the sensor (if removed).
(3) Insert the sensor in the differential housing.
(4) Install the sensor shield.
(5) Install the sensor mounting stud and tighten to
24 N´m (200 in. lbs.).
(6) Install the brake line on the sensor stud and
install the nut.
(7) Lower the vehicle.
TONE WHEEL
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.
HYDRAULIC/MECHANICAL
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 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).
OPERATION - ELECTRONIC VARIABLE BRAKE
PROPORTIONING
EVBP is able to decrease, hold and increase rear
brake pressure without activating full ABS control.
Upon entry into EVBP the inlet valve for the rear
brake circuit is switched on so that the fluid supplyfrom the master cylinder is shut off. In order to
decrease the rear brake pressure, the outlet valve for
the rear brake circuit is pulsed. This allows fluid to
enter the low pressure accumulator (LPA) in the
hydraulic control unit (HCU) resulting in a drop in
fluid pressure to the rear brakes. In order to increase
the rear brake pressure, the outlet valve is switched
off and the inlet valve is pulsed. This increases the
pressure to the rear brakes.
The EVBP will remain functional during many
ABS fault modes. If both the red BRAKE and amber
ABS warning indicators are illuminated, the EVBP
may not be functioning.
HCU (HYDRAULIC CONTROL
UNIT)
DESCRIPTION
The HCU consists of a valve body, pump motor, low
pressure accumulators, inlet valves, outlet valves and
noise attenuators.
OPERATION
Accumulators in the valve body store extra fluid
released to the system for ABS mode operation. The
pump provides the fluid volume needed and is oper-
ated by a DC type motor. The motor is controlled by
the CAB.
The valves modulate brake pressure during
antilock braking 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.
During antilock braking, the solenoid valves are
opened and closed as needed.
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.
NOTE: The three modes mentioned below do occur
but not necessarily in the order listed everytime.
During antilock braking, solenoid valve pressure
modulation occurs in three stages, pressure increase,
pressure hold, and pressure decrease. The valves are
all contained in the valve body portion of the HCU.
PRESSURE DECREASE
The outlet valve is opened and the inlet valve is
closed during the pressure decrease cycle.
A pressure decrease cycle is initiated when speed
sensor signals indicate high wheel slip at one or
more wheels. At this point, the CAB closes the inlet
DRBRAKES - ABS 5 - 43
REAR WHEEL SPEED SENSOR (Continued)

CLUTCH
TABLE OF CONTENTS
page page
CLUTCH
DESCRIPTION..........................1
OPERATION............................1
WARNING.............................2
DIAGNOSIS AND TESTING................2
SPECIFICATIONS........................6
CLUTCH DISC
REMOVAL.............................6
INSTALLATION..........................6
CLUTCH HOUSING
DIAGNOSIS AND TESTING................8
REMOVAL.............................10
INSTALLATION.........................10
CLUTCH RELEASE BEARING
REMOVAL.............................11
INSTALLATION.........................11FLYWHEEL
DIAGNOSIS AND TESTING................11
REMOVAL.............................12
DISASSEMBLY.........................12
ASSEMBLY............................12
INSTALLATION.........................12
PILOT BEARING
REMOVAL.............................12
INSTALLATION.........................12
LINKAGE
REMOVAL.............................13
INSTALLATION.........................13
CLUTCH PEDAL POSITION SWITCH
DESCRIPTION.........................14
OPERATION...........................14
DIAGNOSIS AND TESTING................14
CLUTCH
DESCRIPTION
The clutch mechanism consists of a flywheel, a sin-
gle, dry-type disc, and a diaphragm style clutch cover
(Fig. 1). A hydraulic linkage is used to operate the
clutch release bearing and fork. The flywheel is
bolted to the rear flange of the crankshaft. The
clutch pressure plate is bolted to the flywheel with
the clutch disc located between these two compo-
nents. The clutch system provides the mechanical,
but still easily detachable, link between the engine
and the transmission. The system is designed to
ensure that the full torque output of the engine is
transfered to the transmission while isolating the
transmission from the engine firing pulses to mini-
mize concerns such as gear rattle.
OPERATION
Leverage, clamping force and friction are what
make the clutch work. The disc serves as the friction
element and a diaphragm spring and pressure plate
provide the clamping force. The clutch pedal, hydrau-
lic linkage, release lever and bearing provide the
leverage.
The clutch master cylinder push rod is connected
to the clutch pedal. When the clutch pedal is
depressed, the slave cylinder is operated by the
clutch master cylinder mounted on the dash panel.
The release fork is actuated by the hydraulic slave
cylinder mounted on the transmission housing. Therelease bearing is operated by a release fork pivoting
on a ball stud mounted in the transmission housing.
The release bearing then depresses the pressure
plate spring fingers, releasing pressure on the clutch
disc and allowing the engine crankshaft to spin inde-
pendently of the transmission input shaft (Fig. 2).
Fig. 1 ENGINE POWERFLOW
DRCLUTCH 6 - 1