front brakes DODGE RAM 2001 Service Service Manual

(6) Position adjuster lever return spring on pivot.
(7) Install adjuster lever.
(8) Attach adjuster cable to adjuster lever. Be sure
cable is properly routed.
(9) Adjust brake shoes to drum with brake gauge.
MASTER CYLINDER
DESCRIPTION
A two-piece master cylinder is used on all models.
The cylinder body containing the primary and sec-
ondary pistons is made of aluminum. The removable
fluid reservoir is made of nylon reinforced with glass
fiber. The reservoir stores reserve brake fluid for the
hydraulic brake circuits. The reservoir is the only
serviceable component.
The fluid compartments of the nylon reservoir are
interconnected to permit fluid level equalization.
However, the equalization feature does not affect cir-
cuit separation in the event of a front or rear brake
malfunction. The reservoir compartments will retain
enough fluid to operate the functioning hydraulic cir-
cuit.
Care must be exercised when removing/installing
the master cylinder connecting lines. The threads in
the cylinder fluid ports can be damaged if care is not
exercised. Start all brake line fittings by hand to
avoid cross threading.
The cylinder reservoir can be replaced when neces-
sary. However, the aluminum body section of the
master cylinder is not a repairable component.
NOTE: If diagnosis indicates that an internal mal-
function has occurred, the aluminum body section
must be replaced as an assembly.
OPERATION
The master cylinder bore contains a primary and
secondary piston. The primary piston supplies
hydraulic pressure to the front brakes. The secondary
piston supplies hydraulic pressure to the rear brakes.
DIAGNOSIS AND TESTING - MASTER
CYLINDER/POWER BOOSTER
(1) Start engine and check booster vacuum hose
connections. A hissing noise indicates vacuum leak.
Correct any vacuum leak before proceeding.
(2) Stop engine and shift transmission into Neu-
tral.
(3) Pump brake pedal until all vacuum reserve in
booster is depleted.
(4) Press and hold brake pedal under light foot
pressure. The pedal should hold firm, if the pedal
falls away master cylinder is faulty (internal leak-
age).
(5) Start engine and note pedal action. It should
fall away slightly under light foot pressure then hold
firm. If no pedal action is discernible, power booster,
vacuum supply, or vacuum check valve is faulty. Pro-
ceed to the POWER BOOSTER VACUUM TEST.
(6) If the POWER BOOSTER VACUUM TEST
passes, rebuild booster vacuum reserve as follows:
Release brake pedal. Increase engine speed to 1500
rpm, close the throttle and immediately turn off igni-
tion to stop engine.
(7) Wait a minimum of 90 seconds and try brake
action again. Booster should provide two or more vac-
uum assisted pedal applications. If vacuum assist is
not provided, booster is faulty.
POWER BOOSTER VACUUM TEST
(1) Connect vacuum gauge to booster check valve
with short length of hose and T-fitting (Fig. 54).
(2) Start and run engine at curb idle speed for one
minute.
(3) Observe the vacuum supply. If vacuum supply
is not adequate, repair vacuum supply.
(4) Clamp hose shut between vacuum source and
check valve.
(5) Stop engine and observe vacuum gauge.
(6) If vacuum drops more than one inch HG (33
millibars) within 15 seconds, booster diaphragm or
check valve is faulty.
POWER BOOSTER CHECK VALVE TEST
(1) Disconnect vacuum hose from check valve.
(2) Remove check valve and valve seal from
booster.
(3) Use a hand operated vacuum pump for test.
(4) Apply 15-20 inches vacuum at large end of
check valve (Fig. 55).
Fig. 53 Hold-Down Spring And Pin Attachment
1 - SHOE HOLD DOWN SPRING
2 - HOLD DOWN PIN
3 - BACKING PLATE
4 - BRAKE SHOE WEB
BR/BEBRAKES 5 - 29
BRAKE PADS/SHOES (Continued)

ADJUSTMENT WITH ADJUSTING TOOL
(1) Be sure parking brake lever is fully released.
(2) Raise vehicle so rear wheels can be rotated
freely.
(3) Remove plug from each access hole in brake
support plates.
(4) Loosen parking brake cable adjustment nut
until there is slack in front cable.
(5) Insert adjusting tool through support plate
access hole and engage tool in teeth of adjusting
screw star wheel (Fig. 63).
(6) Rotate adjuster screw star wheel (move tool
handle upward) until slight drag can be felt when
wheel is rotated.
(7) Push and hold adjuster lever away from star
wheel with thin screwdriver.
(8) Back off adjuster screw star wheel until brake
drag is eliminated.
(9) Repeat adjustment at opposite wheel. Be sure
adjustment is equal at both wheels.
(10) Install support plate access hole plugs.
(11) Adjust parking brake cable and lower vehicle.
(12) Drive vehicle and make one forward stop fol-
lowed by one reverse stop. Repeat procedure 8-10
times to operate automatic adjusters and equalize
adjustment.
NOTE: Bring vehicle to complete standstill at each
stop. Incomplete, rolling stops will not activate
automatic adjusters.
PARKING BRAKE
DESCRIPTION ± 2500/3500 WITH REAR DISC
BRAKES
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. 64).
DESCRIPTION - (1500 Models)(Early
2500/3500 models with rear drum brakes)
The parking brakes are operated by a system of
cables and levers attached to the rear brake shoes.
The rear drum brake shoes serve as the parking
brakes. The shoes make contact with the brake drum
surface by a cable and lever mechanism attached to
the secondary brake shoe.
The front parking brake cable is connected to the
parking brake pedal and to an intermediate cable.
The intermediate cable connects the front cable to
the rear cables.
The parking brake pedal assembly is mounted on
the driver side cowl panel. The front cable is directly
attached to the assembly. The pedal assembly con-
tains a spring loaded, torsion-type mechanism that
will hold the cable in the applied position and allow
the pedal to return. A rod used to release the torsion
mechanism and return the pedal to normal position.
Fig. 63 Brake Adjustment
1 - STAR WHEEL
2 - LEVER
3 - BRAKE SHOE WEB
4 - SCREWDRIVER
5 - ADJUSTING TOOL
6 - ADJUSTER SPRING
Fig. 64 SHOES REMOVAL
1 - Park Brake Shoes
2 - Adjuster
3 - Return Springs
4 - Splash Shield
5 - Hold Downs
BR/BEBRAKES 5 - 35
DRUM (Continued)

OPERATION - 2500/3500 WITH REAR DISC
BRAKES
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.
OPERATION - (1500 models) (Early 2500/3500
models with rear drum brakes)
To apply the parking brakes, the pedal is
depressed. This pulls the rear brake shoe actuating
levers forward. As the actuating lever is pulled for-
ward, the parking brake strut or cam, exerts a linear
force against the primary brake shoe. This action
presses the primary shoe into contact with the drum.
Once the primary shoe contacts the drum, force is
exerted through the strut/cam. This force is trans-
ferred through the strut/cam to the secondary brake
shoe causing it to pivot into the drum as well.
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. 65)
from the arm on the pedal assembly.
(9) Remove the bolts/nuts from the pedal assembly
and remove the assembly.
INSTALLATION
(1) Position the replacement pedal assembly on the
dash and cowl.
(2) Install the bolts/nuts and tighten to 28 N´m (21
ft. lbs.).
(3) Connect the front cable to the arm on the pedal
assembly.
(4) Tighten the front cable grommet to the floor-
pan and the cable retainer, roll the carpet back.
(5) Connect the wires to the brake lamp switch.
(6) Install the knee bolster, (Refer to 23 - BODY/
INSTRUMENT PANEL/STEERING COLUMN
OPENING COVER - INSTALLATION).
(7) Raise the vehicle.
(8) Adjust the parking brake cable tensioner.
Fig. 65 Parking Brake Pedal Assembly
1 - PARK BRAKE PEDAL
2 - FRONT CABLE
5 - 36 BRAKESBR/BE
PARKING BRAKE (Continued)

CABLES
REMOVAL - REAR PARK BRAKE CABLE -
2500/3500 WITH REAR DISC BRAKES
(1) Raise and support the vehicle.
(2) Lockout the parking brake cable (Fig. 66).
(3) Loosen cable adjuster nut.
(4) Remove the rear park brake cable from the
intermediate park brake cable.
(5) Compress tabs on cable end fitting on the rear
park brake cable to the frame mount bracket. Then
pull the cable through the bracket.
(6) Disengage the park brake cable from behind
the rotor assembly. (Fig. 67).(7) Compress cable tabs on each cable end fitting
at the brake cable support plate.
(8) Remove the cables from the brake cable sup-
port plates.REMOVAL - FRONT PARKING BRAKE CABLE
(1) Raise and support vehicle.
(2) Loosen adjusting nut to create slack in front
cable.
(3) Remove the front cable from the cable connec-
tor.
(4) Compress cable end fitting at underbody
bracket and remove the cable from the bracket.
(5) Lower vehicle.
(6) Push ball end of cable out of pedal clevis with
small screwdriver.
(7) Compress cable end fitting at the pedal bracket
and remove the cable (Fig. 68).
(8) Remove the left cowl trim and sill plate.
(9) Pull up the carpet and remove the cable from
the body clip.
(10) Pull up on the cable and remove the cable
with the body grommet.
REMOVAL - REAR PARK BRAKE CABLES -
1500 SERIES
(1) Release parking brakes.
(2) Raise and support vehicle.
(3) Loosen cable adjuster nut.
Fig. 66 LOCK OUT PARKING CABLE
1 - LOCKING PLIERS
2 - PARKING BRAKE CABLE
Fig. 67 DISENGAGEMENT OF CABLE
1 - LEVER
2 - CABLE END
Fig. 68 Parking Brake Pedal
1 - PARK BRAKE PEDAL
2 - FRONT CABLE
BR/BEBRAKES 5 - 37

INSTALLATION - FRONT PARKING BRAKE
CABLE
(1) From inside the vehicle, insert the cable end
fitting into the hole in the pedal assembly.
(2) Seat the cable retainer in the pedal assembly.
(3) Engage the cable ball end in clevis on the pedal
assembly.
(4) Route the cable along the top of the wheel well
and clip in place.
(5) Route the cable through the floorpan and
install the body grommet.
(6) Place the carpet down and install the left cowl
trim and sill plate.
(7) Raise and support the vehicle.
(8) Route the cable through the underbody bracket
and seat the cable housing retainer in the bracket.
(9) Connect the cable to the cable connector.
(10) Perform the park brake adjustment proce-
dure, (Refer to 5 - BRAKES/PARKING BRAKE/CA-
BLE TENSIONER - ADJUSTMENTS).
(11) Lower the vehicle.
INSTALLATION - REAR PARK BRAKE CABLES -
1500 SERIES
(1) Install the parking brake cable guide spring.
(2) Install the brake drums.
(3) Pull back on the cable. Then push the cable
through the brake support plate hole to engage the
cable in the park brake lever.
NOTE: Pull on the cable end to ensure it is attached
to the park brake lever.
(4) Push each cable end through the brake support
plate hole until the cable end fitting tabs lock into
place.
NOTE: Pull on the cable to ensure it is locked into
place.
(5) Install the right cable retainers on the axle.
Route the right cable through the hole in the brake
hose bracket.
(6) Push both cables through the frame bracket.
NOTE: The right cable must be installed in the top
hole of the bracket.(7) Lock the left cable end fitting tabs into the
frame bracket lower hole.
(8) Install the right rear cable into the tensioner
cable bracket and lock the cable end fitting tabs into
place.
(9) Install the cables onto the cable connectors.
(10) Install the wheel and tire assemblies, (Refer
to 22 - TIRES/WHEELS/WHEELS - STANDARD
PROCEDURE).
(11) Perform the park brake adjustment procedure,
(Refer to 5 - BRAKES/PARKING BRAKE/CABLE
TENSIONER - ADJUSTMENTS).
(12) Remove the supports and lower the vehicle.
INSTALLATION - REAR PARK BRAKE CABLE
2500/3500 SERIES WITH DRUM BRAKES
(1) Install cable guide spring.
(2) Install the brake drums.
(3) Pull back on the cable. Then push the cable
through the brake support plate hole to engage the
cable in the park brake lever.
NOTE: Pull on the cable end to ensure it is attached
to the park brake lever.
(4) Push each cable housing through the brake
support plate hole until the cable end fitting tabs
lock into place.
NOTE: Pull on the cable housing to ensure it is
locked into place.
(5) Install the right cable retainers on the axle.
The push the right cable through the hole in the
brake hose bracket.
(6) Push both cables through the frame bracket.
Push the left cable until the cable end fitting tabs
lock into place. Install the O-ring on the right cable.
NOTE: The right cable must be installed in the top
hole of the bracket and left cable in the bottom
hole.
(7) Install the cables onto the cable tensioner
bracket and install the cables into the cable connec-
tors.
(8) Install the wheel and tire assemblies.
(9) Perform park brake adjustment procedure.
(10) Remove supports and lower vehicle.
BR/BEBRAKES 5 - 39
CABLES (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
6. Coolant mixture incorrect. 6. Drain cooling system (Refer to 7 -
COOLING - STANDARD
PROCEDURE) refill with correct
mixture (Refer to 7 - COOLING -
STANDARD PROCEDURE).
7. Thermostat stuck shut. 7. Replace thermostat.
8. Bug screen or winter front being
used.8. Remove bug screen or winter
front.
9. Viscous fan drive not operating
properly.9. Check viscous fan (Refer to 7 -
COOLING/ENGINE/FAN DRIVE
VISCOUS CLUTCH - DIAGNOSIS
AND TESTING)
10. Cylinder head gasket leaking. 10. Check for leaking head gaskets
(Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).
11. Heater core leaking. 11. Replace heater core.
12. cooling system hoses leaking. 12. Tighten clamps or Replace
hoses.
13. Brakes dragging. 13. Check brakes. (Refer to 5 -
BRAKES/HYDRAULIC/
MECHANICAL - DIAGNOSIS AND
TESTING)
TEMPERATURE GAUGE READING
INCONSISTENT ( ERRATIC,
CYCLES OR FLUCTUATES)1. Heavy duty cooling system,
extream cold ambient (outside)
temperature or heater blower motor
in high position.1. None. System operating normaly.
2. Temperature gauge or gauge
sensor defective.2. Check gauge. (Refer to 8 -
ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND
TESTING)
3. Temporary heavy usage or load. 3. None. Normal condition.
4. Air traped in cooling system. 4. Fill cooling system (Refer to 7 -
COOLING - STANDARD
PROCEDURE).
5. Water pump 5. Replace water pump.
6. Air leak on suction side of water
pump.6. Check for leak. (Refer to 7 -
COOLING - DIAGNOSIS AND
TESTING)
RADIATOR CAP LEAKING STEAM
AND /OR COOLANT INTO
RESERVOIR BOTTLE.
(TEMPERATURE GAUGE MAY
READ HIGH)1. Radiator cap defective. 1. Replace radiator cap.
2. Radiator neck surface damaged. 2. Replace radiator.
BR/BECOOLING 7 - 13
COOLING (Continued)

WIRING
TABLE OF CONTENTS
page page
WIRING DIAGRAM INFORMATION....... 8W-01-1
COMPONENT INDEX.................. 8W-02-1
POWER DISTRIBUTION............... 8W-10-1
JUNCTION BLOCK.................... 8W-12-1
GROUND DISTRIBUTION.............. 8W-15-1
BUS COMMUNICATIONS.............. 8W-18-1
CHARGING SYSTEM.................. 8W-20-1
STARTING SYSTEM.................. 8W-21-1
FUEL/IGNITION SYSTEM.............. 8W-30-1
TRANSMISSION CONTROL SYSTEM..... 8W-31-1
VEHICLE SPEED CONTROL............ 8W-33-1
REAR WHEEL ANTILOCK BRAKES....... 8W-34-1
ALL WHEEL ANTILOCK BRAKES........ 8W-35-1
VEHICLE THEFT SECURITY SYSTEM..... 8W-39-1
INSTRUMENT CLUSTER............... 8W-40-1
HORN/CIGAR LIGHTER/POWER OUTLET . . 8W-41-1
AIR CONDITIONING-HEATER........... 8W-42-1
AIRBAG SYSTEM.................... 8W-43-1INTERIOR LIGHTING.................. 8W-44-1
CENTRAL TIMER MODULE............. 8W-45-1
AUDIO SYSTEM..................... 8W-47-1
OVERHEAD CONSOLE................. 8W-49-1
FRONT LIGHTING.................... 8W-50-1
REAR LIGHTING..................... 8W-51-1
TURN SIGNALS...................... 8W-52-1
WIPERS............................ 8W-53-1
TRAILER TOW....................... 8W-54-1
POWER WINDOWS................... 8W-60-1
POWER DOOR LOCKS................ 8W-61-1
POWER MIRRORS................... 8W-62-1
POWER SEATS...................... 8W-63-1
SPLICE INFORMATION................ 8W-70-1
CONNECTOR PIN-OUTS............... 8W-80-1
CONNECTOR/GROUND LOCATIONS...... 8W-90-1
SPLICE LOCATIONS.................. 8W-95-1
POWER DISTRIBUTION............... 8W-97-1 BR/BEWIRING 8W - 1

8W-35 ALL WHEEL ANTILOCK BRAKES
Component Page
Brake Lamp Switch.................. 8W-35-4
Brake Pressure Switch................ 8W-35-4
Controller Antilock Brake.......... 8W-35-2, 3, 4
Engine Control Module................ 8W-35-4
Fuse 3 (JB)......................... 8W-35-2
Fuse 11 (PDC)....................... 8W-35-2
G100.............................. 8W-35-4
G101.............................. 8W-35-3
G107.............................. 8W-35-3
G200.............................. 8W-35-4
Instrument Cluster................... 8W-35-3Component Page
Joint Connector No. 1................. 8W-35-4
Joint Connector No. 3................. 8W-35-3
Joint Connector No. 4................. 8W-35-4
Joint Connector No. 7................. 8W-35-3
Junction Block...................... 8W-35-2
Left Front Wheel Speed Sensor......... 8W-35-2
Power Distribution Center............. 8W-35-2
Powertrain Control Module............. 8W-35-4
Rear Wheel Speed Sensor.............. 8W-35-2
Right Front Wheel Speed Sensor........ 8W-35-2
BR/BE8W-35 ALL WHEEL ANTILOCK BRAKES 8W - 35 - 1

(23) Inspect for exhaust system restrictions such
as pinched exhaust pipes, collapsed muffler or
plugged catalytic convertor.
(24) If equipped with automatic transmission, ver-
ify that electrical harness is firmly connected to park/
neutral switch. Refer to 21, Automatic Transmission.
(25) Verify electrical harness is firmly connected to
rear wheel speed sensor. Verify rear wheel speed sen-sor is firmly attached to rear axle with proper air
gap. Refer to 5, Brakes for information.
(26) If equipped with 4±wheel antilock brake sys-
tem, verify electrical harness is firmly connected to
each front wheel speed sensor. Verify both front
wheel speed sensors are firmly attached. Refer to 5,
Brakes for information.
(27) Verify that fuel pump/gauge sender unit wire
connector is firmly connected to harness connector.
(28) Inspect fuel hoses at fuel pump/gauge sender
unit for cracks or leaks.
(29) Inspect transmission torque convertor housing
(automatic transmission) or clutch housing (manual
transmission) for damage to timing ring on drive
plate/flywheel.
(30) Verify that battery cable and solenoid feed
wire connections to the starter solenoid are tight and
clean. Inspect for chaffed wires or wires rubbing up
against other components.
Fig. 8 Engine Coolant Temperature
1 - GENERATOR
2 - A/C COMPRESSOR
3 - ENGINE COOLANT TEMPERATURE SENSOR
4 - ELEC. CONN.
Fig. 9 Left/Right Oxygen SensorsÐHDC Engines
1 - DUAL OXYGEN SENSORS
2 - TOP OF TRANSMISSION
Fig. 10 Pre-Catalyst/Post-Catalyst Sensors
1 - POST CATALYST OXYGEN SENSOR (1/3)
2 - PRE-CATALYST OXYGEN SENSOR (1/2)
Fig. 11 Oxygen Sensors
BR/BEFUEL INJECTION - GASOLINE 14 - 31
FUEL INJECTION - GASOLINE (Continued)

(25) Verify electrical harness is firmly connected to
rear wheel speed sensor. Verify rear wheel speed sen-
sor is firmly attached to rear axle with proper air
gap. Refer to 5, Brakes for information.
(26) If equipped with 4±wheel antilock brake sys-
tem, verify electrical harness is firmly connected to
each front wheel speed sensor. Verify both front
wheel speed sensors are firmly attached. Refer to 5,
Brakes for information.
(27) Verify that fuel pump/gauge sender unit wire
connector is firmly connected to harness connector.
(28) Inspect fuel hoses at fuel pump/gauge sender
unit for cracks or leaks.
(29) Inspect transmission torque convertor housing
(automatic transmission) or clutch housing (manual
transmission) for damage to timing ring on drive
plate/flywheel.
(30) Verify that battery cable and solenoid feed
wire connections to the starter solenoid are tight and
clean. Inspect for chaffed wires or wires rubbing up
against other components.
Fig. 18 Upstream/Downstream Oxygen Sensors
1 - DOWN STREAM OXYGEN SENSOR (1/2)
2 - UP STREAM OXYGEN SENSOR (1/1)
Fig. 19 Left/Right
1 - DUAL OXYGEN SENSORS
2 - TOP OF TRANSMISSION
Fig. 20 Pre-Catalyst/Post Catalyst Oxygen Sensors
1 - POST CATALYST OXYGEN SENSOR (1/3)
2 - PRE-CATALYST OXYGEN SENSOR (1/2)
14 - 34 FUEL INJECTION - GASOLINEBR/BE
FUEL INJECTION - GASOLINE (Continued)