2003 JEEP GRAND CHEROKEE Wheel nut

STANDARD PROCEDURE - MASTER CYLINDER
BLEEDING PROCEDURE
A new master cylinder should be bled before instal-
lation on the vehicle. Required bleeding tools include
bleed tubes and a wood dowel to stroke the pistons.
Bleed tubes can be fabricated from brake line.
(1) Mount master cylinder in vise with brass jaws.
(2) Attach bleed tubes to cylinder outlet ports.
Then position each tube end into the bottom of the
reservoir (Fig. 50).
(3) Fill reservoir with fresh brake fluid.
(4) Press cylinder pistons inward with wood dowel.
Then release pistons and allow them to return under
spring pressure. Continue bleeding operations until
air bubbles are no longer visible in fluid.
REMOVAL
(1) Remove the wire connector from the brake fluid
level sensor.
(2) Remove brake lines from master cylinder.
(3) Remove nuts that attach master cylinder to
booster studs (Fig. 51).
(4) Remove master cylinder from booster.
INSTALLATION
NOTE: Bleed new master cylinder on bench before
installation, refer to Service Procedures.
(1) Have an assistant depress the brake pedal
while guiding the master cylinder on the booster rod
and mounting studs.
CAUTION: Do not depress brake pedal too hard and
ensure the booster rod is in the master cylinder pis-
ton or booster/master cylinder damage will occur.(2) Install master cylinder mounting nuts and
tighten nuts to 25 N´m (18 lb. lbs.).
NOTE: Use original or factory replacement nuts only.
(3) Install brake lines and tighten to 16 N´m (144
in. lbs.).
(4) Install fluid level sensor connector.
(5) Fill and bleed brake system.
PEDAL
DESCRIPTION
DESCRIPTION - STANDARD PEDAL
A suspended-type brake pedal is used, the pedal
pivots on a shaft mounted in the pedal support
bracket. The bracket is attached to the dash panel.
The brake pedal assembly and pedal pad are the
only serviceable component.
DESCRIPTION - ADJUSTABLE PEDALS
The Adjustable Pedals System (APS) is designed to
enable the fore and aft repositioning of the brake and
accelerator pedals. This results in improved ergonom-
ics in relation to the steering wheel for taller and
shorter drivers. Being able to adjust the pedal posi-
Fig. 50 Master Cylinder Bleeding
1 - BLEEDING TUBES
2 - RESERVOIR
Fig. 51 Master Cylinder Mounting
1 - MOUNTING NUT
2 - SENSOR CONNECTOR
3 - MOUNTING NUT
4 - BRAKE LINES
WJBRAKES - BASE 5 - 25
MASTER CYLINDER (Continued)

(2) Remove nut from pedal shaft.
(3) Slide pedal shaft out and remove brake pedal.
(4) Remove pedal bushings (Fig. 54) if they are to
be replaced.
REMOVAL - ADJUSTABLE PEDALS
NOTE: If possible put the pedals in the full forward
position.
(1) Disconnect the negative battery cable.
(2) Remove the cluster bezel (Refer to 23 - BODY/
INSTRUMENT PANEL/CLUSTER BEZEL - REMOV-
AL).
(3) Remove the steering column opening cover
(Refer to 23 - BODY/INSTRUMENT PANEL/STEER-
ING COLUMN OPENING COVER - REMOVAL).
(4) Disconnect the module electrical connector.
(5) Remove the brake light switch.
(6) Disconnect the booster rod clip (Fig. 53).
(7) Disconnect the accelerator cable from the
pedal.
(8) Lock the steering wheel into place.
(9) Remove the lower steering shaft pinch bolt
(Fig. 56).
(10) Separate the lower shaft coupler and push for-
ward (Fig. 56).
(11) Remove the two pedal bracket upper nuts
(Fig. 55).
(12) Remove the brake booster nuts (Fig. 56).
(13) Remove the accelerator pedal nuts (Fig. 57).(14) Remove the ICU mounting bracket nuts and
bolts and move the ICU and booster forward this will
allow enough clearance to remove the adjustable
pedal bracket from over the booster push rod.
(15) Remove the pedal from the vehicle (Fig. 56).
(16) Transfer the module if needed.
Fig. 54 Pedal Bushings
1 - BUSHING
2 - BUSHING
3 - SHAFT NUT
4 - PEDAL SHAFT
Fig. 55 UPPER MOUNTING NUTS
1 - UPPER MOUNTING STUDS
2 - ACCELERATOR MOUNTING STUDS
3 - UPPER MOUNTING NUT
4 - MOTOR
5 - ADJUSTABLE PEDAL BRACKET
Fig. 56 ADJUSTABLE PEDAL BRACKET
1 - BRAKE LIGHT SWITCH
2 - STEERING COLUMN
3 - ACCELERATOR PEDAL
4 - ADJUSTABLE PEDALS MOUNTING BRACKET
5 - BRAKE PEDAL
6 - MOTOR MOUNTING BRACKET
7 - BRAKE BOOSTER MOUNTING NUTS
(4)
WJBRAKES - BASE 5 - 27
PEDAL (Continued)

INSTALLATION
INSTALLATION - NON-ADJUSTABLE PEDAL
(1) Lubricate bushings, pedal shaft and pedal pin
with Mopar multi-mileage grease.
(2) Install bushings into pedal.
(3) Position pedal in bracket and install pedal
shaft in support and through pedal.
(4) Install new nut on pedal shaft and tighten to
27 N´m (20 ft. lbs.).
NOTE: Pedal shaft nut should not be reused.
(5) Install booster push rod on pedal pin and
install retainer clip on pedal pin.
(6) Check and adjust stop lamp switch if necessary.
INSTALLATION - ADJUSTABLE PEDALS
(1) Install the pedal to the vehicle (Fig. 56).
(2) Reposition the ICU and booster, Install the
ICU mounting bracket nuts and bolts.
28 N
(3) Install the brake booster nuts. Tighten to 28
N´m ( 21 ft. lbs.). (Fig. 56).
(4) Install the pedal bracket upper nuts. Tighten
to 12 N´m ( 9 ft. lbs.). (Fig. 56).
(5) Install the accelerator pedal nuts. Tighten to
28 N´m ( 21 ft. lbs.). (Fig. 57).
(6) Install the lower steering shaft coupler over the
shaft (Fig. 56).
(7) Install the lower steering shaft pinch bolt (Fig.
56).
(8) Unlock the steering wheel.
(9) Reconnect the accelerator cable to the pedal
(Fig. 56).(10) Reconnect the booster rod clip (Fig. 56).
(11) Install the brake light switch.
(12) Reconnect the module electrical connector.
(13) Install the steering column opening cover
(Refer to 23 - BODY/INSTRUMENT PANEL/STEER-
ING COLUMN OPENING COVER - INSTALLA-
TION).
(14) Install the cluster bezel (Refer to 23 - BODY/
INSTRUMENT PANEL/CLUSTER BEZEL -
INSTALLATION).
(15) Reconnect the negative battery cable.
PEDAL MOTOR
REMOVAL
(1) Disconnect the negative battery cable.
(2) Remove the cluster bezel (Refer to 23 - BODY/
INSTRUMENT PANEL/CLUSTER BEZEL - REMOV-
AL).
(3) Remove the steering column opening cover
(Refer to 23 - BODY/INSTRUMENT PANEL/STEER-
ING COLUMN OPENING COVER - REMOVAL).
(4) Remove the two mounting screws (Fig. 58).
(5) Disconnect the electrical connector (Fig. 58).
(6) Remove the adjustable pedal motor (Fig. 58).
INSTALLATION
(1) Install the adjustable pedal motor (Fig. 58).
(2) Reconnect the electrical connector (Fig. 58).
(3) Install the two mounting screws (Fig. 58).
(4) Install the steering column opening cover
(Refer to 23 - BODY/INSTRUMENT PANEL/STEER-
ING COLUMN OPENING COVER - INSTALLA-
TION).
Fig. 57 ACCELERATOR MOUNTING BRACKET
1 - ACCELERATOR MOUNTING NUTS
2 - ADJUSTABLE PEDALS BRACKET
3 - ACCELERATOR PEDAL
Fig. 58 ADJUSTABLE PEDALS MOTOR
1 - ELECTRICAL CONNECTOR
2 - PEDALS MOTOR
3 - MOUNTING SCREWS HOLES
5 - 28 BRAKES - BASEWJ
PEDAL (Continued)

Measure rotor thickness a minimum of six points
around the rotor face. Position the micrometer approx-
imately 19 mm (3/4 in.) from the rotor outer circumfer-
ence for each measurement (Fig. 62).
Thickness should not vary by more than 0.0127 mm
(0.0005 in.) from point to point on the rotor. Refinish or
replace the rotor if necessary.
NOTE: A hub mounted on-vehicle lathe is recom-
mended. This type of lathe trues the rotor to the vehi-
cles hub/bearing.
CAUTION: For vehicles equipped with the Quadra-
Drive System, consisting of the NV-247 transfer case
and a Vari-Lok differential in the front and rear axles,
the following steps must be done prior to the use of a
hub mounted on-vehicle brake lathe. Disconnect the
driveshaft (Refer to 3 - DIFFERENTIAL & DRIVELINE/
PROPELLER SHAFT/PROPELLER SHAFT - REMOVAL)
from the respective axle on which the brake rotors are
being machined. Temporarily remove both brake cali-
pers (Refer to 5 - BRAKES/HYDRAULIC/MECHANICAL/
DISC BRAKE CALIPERS - REMOVAL) from the axle
while disc rotor machining is in process. Both steps
will prevent unnecessary loads to the hub mounted
on-vehicle lathe and speed machining times. Install a
thread lock material to the driveshaft attaching bolts
when reinstalling (Refer to 3 - DIFFERENTIAL & DRIV-
ELINE/PROPELLER SHAFT/PROPELLER SHAFT -
INSTALLATION).
Front rotors and hub/bearings are matched mounted
for minimum lateral runout. Before removing the rotor,
mark the rotor and hub/bearing to maintain original
orientation.
FRONT ROTOR LATERAL RUNOUT
Check rotor lateral runout whenever pedal pulsation,
or rapid, uneven brake lining wear has occurred.
The rotor must be securely clamped to the hub to
ensure an accurate runout measurement. Secure therotor with a minimum of 3 lug nuts and large diameter
flat washers on each stud.
Use a dial indicator to check lateral runout (Fig. 63).
Maximum allowable rotor lateral runout is 0.05 mm
(0.002 in.).
DIAGNOSIS AND TESTING - REAR DISC
BRAKE ROTOR
ROTOR MINIMUM THICKNESS
Minimum usable thickness of the rear disc brake
rotor is 8.5 mm (0.335 in.). The thickness specification
is located on the center section of the rotor.
Never resurface a rotor if machining would cause
thickness to fall below this limit.
Measure rotor thickness at the center of the brake
shoe contact surface. Replace the rotor if worn below
minimum thickness, or if refinishing would reduce
thickness below the allowable minimum.
REAR ROTOR THICKNESS VARIATION
Variations in rotor thickness will cause pedal pulsa-
tion, noise and shudder.
Measure rotor thickness at a minimum of six points
around the rotor face. Position the micrometer approxi-
mately 19 mm (3/4 in.) from the rotor outer circumfer-
ence for each measurement (Fig. 62).
Thickness should not vary by more than 0.0127 mm
(0.0005 in.) from point to point on the rotor. Refinish or
replace the rotor if necessary.
REAR ROTOR LATERAL RUNOUT
Check rotor lateral runout whenever diagnosis indi-
cates pedal pulsation and rapid, uneven brake lining
wear.
The rotor must be securely clamped to the hub to
ensure an accurate runout measurement. Secure the
rotor with the wheel nuts and 4 or 5 large diameter flat
washers on each stud.
Use a dial indicator to check lateral runout (Fig. 63).
Maximum allowable lateral runout is 0.76 mm (0.003 in.).
Fig. 62 Measuring Rotor Thickness Variation
1 - MICROMETER
2 - ROTOR
Fig. 63 Checking Rotor Lateral Runout
1 - DIAL INDICATOR
5 - 32 BRAKES - BASEWJ
ROTORS (Continued)
2002 WJ Service Manual
Publication No. 81-370-02064
02WJ5-32 June, 2002

(7) Raise and support the vehicle.
(8) Remove the wheel and tire assemblies.
(9) Remove the brake calipers, caliper anchors and
rotors.
(10) Remove the ABS sensor wiring harness (Fig.
74)from the rear brake cables.
(11) Remove the cable retainer bolts (Fig. 74) from
the rear spring pads.
(12) Pull the cables out of the upper suspension
arm brackets.
(13) Push the cable in and lift up the end of cable
with a small screw driver to disengage the cable from
the parking brake actuator (Fig. 75).
(14) Remove the cable from the vehicle.
INSTALLATION
INSTALLATION - FRONT PARKING BRAKE
CABLE
(1) Install thecable into the parking brake lever
bracket and equalizer bracket.
(2) Install the front cable to the floor pan and
install retainer nuts.
(3) Engage the front cable ends to the parking
brake lever and equalizer.
(4) Install the front carpet, (Refer to 23 - BODY/
INTERIOR/CARPETS AND FLOOR MATS -
INSTALLATION).
(5) Pull on the lever to release the lock out spring.
(6) Install the center console, (Refer to 23 - BODY/
INTERIOR/FLOOR CONSOLE - INSTALLATION).
(7) Fold down the rear carpet cover and rear seat.
INSTALLATION - REAR PARKING BRAKE
CABLES
(1) Install the cables through the caliper anchor
mount. Then push the end of cable strand in to
engage the cable end to the parking brake actuator.
(2) Feed the other end of the cables through the
body and into the equalizer bracket (Fig. 76).
Fig. 74 Left Rear Parking Brake Cable
1 - CABLE BRACKET
2 - UPPER SUSPENSION ARM
3 - PARKING BRAKE CABLE
4 - CABLE RETAINER
5 - ABS SENSOR WIRING
Fig. 75 Parking Brake
1 - CABLE END
2 - SCREW DRIVER
3 - PARKING BRAKE ACTUATOR
4 - BRAKE SHOES
Fig. 76 Equalizer Bracket
1 - EQUALIZER
2 - RIGHT REAR CABLE
3 - LEFT REAR CABLE
4 - FRONT CABLE
WJBRAKES - BASE 5 - 37
CABLES (Continued)

(8) Remove the park brake lever mounting nuts
and console bracket (Fig. 80).
(9) Lift the lever assembly off the mounting studs
and pull the front cable out of the lever bracket.
INSTALLATION
(1) Install the lever assembly on the mounting
studs while feeding the front cable into the lever
bracket.
(2) Install the console bracket (Fig. 80) and mount-
ing nuts.
(3) Engage the front cable end to the lever.
(4) Connect parking brake switch wire connector.
(5) Pull on the lever to release the lock out spring.
(6) Install center console,(Refer to 23 - BODY/IN-
TERIOR/FLOOR CONSOLE - INSTALLATION).
(7) Fold down the rear carpet cover and rear seat.
SHOES
REMOVAL
(1) Lock out park brake lever (Fig. 81).
(2) Raise vehicle.
(3) Remove rear wheel and tire assembly.
(4) Remove caliper and anchor as an assembly.
(5) Remove rubber access plug from back of rear
disc brake splash shield.
(6) If necessary retract parking brake shoes with
brake adjuster tool (Fig. 82). Position tool at top of
star wheel and rotate wheel.
(7) Remove rotor from axle hub flange.
(8) Remove the lower shoe to shoe spring/adjuster
spring with needle nose pliers (Fig. 83).
(9) Remove the upper shoe to shoe spring/return
spring with brake pliers (Fig. 84).(10) Remove shoe hold-down clips and pins (Fig.
85). Clip is held in place by pin which fits in clip
notch. To remove clip, first push clip ends together
and slide clip until head of pin clears narrow part of
notch. Then remove clip and pin.
(11) Remove shoes and adjuster.
INSTALLATION
(1) Install shoes on splash shield with hold down
clips and pins. Be sure shoes are properly engaged in
the park brake actuator.
(2) Lubricate and install adjuster screw assembly.
Be sure notched ends of screw assembly are properly
seated on shoes and that star wheel is aligned with
access hole in shield.
Fig. 80 Parking Brake Lever Mounting
1 - MOUNTING NUT
2 - PARK BRAKE LEVER
Fig. 81 Lock Out Spring
1 - LOCK OUT SPRING
Fig. 82 Retracting Parking Brake Shoes
1 - ACCESS HOLE
2 - BRAKE ADJUSTING TOOL
3 - SPLASH SHIELD
WJBRAKES - BASE 5 - 39
LEVER (Continued)

(3) Install lower shoe to shoe spring/adjuster
spring. Needle nose pliers can be used to connect
spring to each shoe.
(4) Install the upper shoe to shoe spring/return
spring with brake pliers (Fig. 83).
(5) Install rotor and caliper anchor assembly.
(6) Install anchor bolts and tighten to 90-115 N´m
(66-85 ft. lbs.).
(7) Actuate park brake lever to unlock the park
brake system.
(8) Adjust the parking brake shoes (Fig. 82).
(9) Install wheel and tire assembly.
(10) Lower vehicle and verify correct parking
brake operation.
ADJUSTMENTS - PARKING BRAKE SHOE
(1) Remove wheel and tire assemblies.
(2) Secure rotor with two wheel nuts.
(3) Remove rubber access plug from back of splash
shield.
(4) Insert brake tool through access hole in splash
shield (Fig. 86). Position tool at bottom of star wheel.
(5) Rotate star wheel upward direction to expand
shoes (while facing front of vehicle).
(6) Expand shoes until light drag is experienced.
Then back off adjuster screw only enough to elimi-
nate drag.
(7) Install plug in splash shield access hole.
(8) Install wheel and tire assemblies.
Fig. 83 Lower Spring
1 - REAR SHOE
2 - NEEDLENOSE PLIERS
3 - ADJUSTER SCREW
4 - LOWER SPRING
Fig. 84 Upper Spring
1 - BRAKE PLIERS
2 - REAR SHOE
3 - UPPER SPRING
Fig. 85 Hold-Down Clip And Pin
1 - HOLD-DOWN CLIP
2 - HOLD-DOWN PIN
Fig. 86 Park Brake Shoe Adjustment
1 - ACCESS HOLE
2 - BRAKE ADJUSTING TOOL
3 - SPLASH SHIELD
5 - 40 BRAKES - BASEWJ
SHOES (Continued)

FAN DRIVE VISCOUS CLUTCH
- 4.0L
DESCRIPTION
CAUTION: Engines equipped with serpentine drive
belts have reverse rotating fans and viscous fan
drives. They are marked with the word REVERSE to
designate their usage. Installation of the wrong fan
or viscous fan drive can result in engine overheat-
ing.
CAUTION: If the viscous fan drive is replaced
because of mechanical damage, the cooling fan
blades should also be inspected. Inspect for fatigue
cracks, loose blades, or loose rivets that could
have resulted from excessive vibration. Replace fan
blade assembly if any of these conditions are
found. Also inspect water pump bearing and shaft
assembly for any related damage due to a viscous
fan drive malfunction.
The thermal viscous fan drive (Fig. 27) is a sili-
cone-fluid-filled coupling used to connect the fan
blades to the water pump shaft. The coupling allows
the fan to be driven in a normal manner. This is
done at low engine speeds while limiting the top
speed of the fan to a predetermined maximum level
at higher engine speeds.
An electrical cooling fan located in the fan shroud
aids in low speed cooling, It is designed to augment
the viscous fan, However, it does not replace the vis-
cous fan.
OPERATION
A thermostatic bimetallic spring coil is located on
the front face of the viscous fan drive unit (Fig. 27).
This spring coil reacts to the temperature of the radi-
ator discharge air. It engages the viscous fan drive
for higher fan speed if the air temperature from the
radiator rises above a certain point. Until additional
engine cooling is necessary,the fan will remain at
a reduced rpm regardless of engine speed. Nor-
mally less than three hundred (300) rpm.
Only when sufficient heat is present, will the vis-
cous fan drive engage. This is when the air flowing
through the radiator core causes a reaction to the
bimetallic coil. It then increases fan speed to provide
the necessary additional engine cooling.
Once the engine has cooled, the radiator discharge
temperature will drop. The bimetallic coil again
reacts and the fan speed is reduced to the previous
disengaged speed.
DIAGNOSIS AND TESTINGÐVISCOUS FAN
DRIVE
If the fan assembly free-wheels without drag (the
fan blades will revolve more than five turns when
spun by hand), replace the fan drive. This spin test
must be performed when the engine is cool.
For the following test, the cooling system must be
in good condition. It also will ensure against exces-
sively high coolant temperature.
WARNING: BE SURE THAT THERE IS ADEQUATE
FAN BLADE CLEARANCE BEFORE DRILLING.
(1) Drill a 3.18-mm (1/8-in) diameter hole in the
top center of the fan shroud.
(2) Obtain a dial thermometer with an 8 inch stem
(or equivalent). It should have a range of -18É to
105ÉC (0É to 220É F). Insert thermometer through the
hole in the shroud. Be sure that there is adequate
clearance from the fan blades.
(3) Connect a tachometer and an engine ignition
timing light (timing light is to be used as a strobe
light).
(4) Block the air flow through the radiator. Secure
a sheet of plastic in front of the radiator (or air con-
ditioner condenser). Use tape at the top to secure the
plastic and be sure that the air flow is blocked.
(5) Be sure that the air conditioner (if equipped) is
turned off.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR FAN. DO
NOT WEAR LOOSE CLOTHING.
Fig. 27 Viscous Fan Drive
1 - VISCOUS FAN DRIVE
2 - THERMOSTATIC SPRING
3 - MOUNTING NUT TO WATER PUMP HUB
7 - 40 ENGINEWJ