2003 JEEP GRAND CHEROKEE prop shaft

(14) Remove rear bearing cup from housing (Fig.
77) with Remover C-4307 and Handle C-4171.
(15) Remove collapsible preload spacer (Fig. 78).
(16) Remove rear bearing from the pinion with
Puller/Press C-293-PA and Adapters C-293-42 (Fig.
79).
(17) Remove depth shims from the pinion gear
shaft and record shim thickness.
INSTALLATION
NOTE: A pinion depth shim/oil slinger is placed
between the rear pinion bearing cone and the pin-
ion head to achieve proper ring gear and pinion
mesh. If ring gear and pinion are reused, the pinion
depth shim/oil slinger should not require replace-
ment. Refer to Adjustment (Pinion Gear Depth) to
select the proper thickness shim/oil slinger if ring
and pinion gears are replaced.
Fig. 77 Rear Pinion Bearing Cup
1 - REMOVER
2 - HANDLE
Fig. 78 Collapsible Spacer
1 - COLLAPSIBLE SPACER
2 - SHOULDER
3 - PINION GEAR
4 - DEPTH SHIM
5 - REAR BEARING
Fig. 79 Rear Pinion Bearing Puller
1 - PULLER
2 - VISE
3 - ADAPTERS
4 - PINION GEAR SHAFT
3 - 126 REAR AXLE - 226RBAWJ
PINION GEAR/RING GEAR (Continued)

(13) Check bearing rotating torque with a inch
pound torque wrench (Fig. 87). The pinion gear rotat-
ing torque should be:
²
Original Bearings: 1 to 2.25 N´m (10 to 20 in. lbs.).
²New Bearings: 2.8 to 4 N´m (25 to 35 in. lbs.).
(14) Invert the differential case and start two ring
gear bolts. This will provide case-to-ring gear bolt
hole alignment.
(15) Invert the differential case in the vise.
(16) Installnewring gear bolts and alternately
tighten to 129-142 N´m (95-105 ft. lbs.) (Fig. 88).
CAUTION: Never reuse the ring gear bolts. The
bolts can fracture causing extensive damage.
NOTE: If equipped with Veri-LokTdifferential install
oil feed plenum and side bearing.
(17) Install differential in housing.
CAUTION: When installing a Vari-lokTdifferential
(Fig. 89), the oil feed tube must point to the bottom
of the housing. If differential is installed with the oil
feed tube pointed toward the top, the anti-rotation
tabs will be damaged.
(18)
Verify differential bearing preload, gear mesh
and contact pattern. Refer to Ajustments for procedure.
(19) Install differential cover and fill with gear
lubricant.(20) Install the propeller shaft with the reference
marks aligned.
(21) Remove supports and lower vehicle.
Fig. 87 PINION ROTATING TORQUE
1 - PINION YOKE/COMPANION FLANGE
2 - INCH POUND TORQUE WRENCH
Fig. 88 RING GEAR
1 - TORQUE WRENCH
2 - RING GEAR BOLT
3 - RING GEAR
4 - CASE
Fig. 89 VARI-LOK
1 - ANTI-ROTATION TAB
2 - OIL FEED TUBE
WJREAR AXLE - 226RBA 3 - 129
PINION GEAR/RING GEAR (Continued)

Common causes of brake drag are:
²Parking brake partially applied.
²Loose/worn wheel bearing.
²Seized caliper.
²Caliper binding.
²Loose caliper mounting.
²Mis-assembled components.
²Damaged brake lines.
If brake drag occurs at the front, rear or all
wheels, the problem may be related to a blocked mas-
ter cylinder return port, faulty power booster (binds-
does not release) or the ABS system.
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:
²Contaminated lining in one caliper
²Seized caliper piston
²Binding caliper
²Loose caliper
²Rusty caliper slide surfaces
²Improper brake shoes
²Damaged rotor
²Wheel alignment.
²Tire pressure.
A worn, damaged wheel bearing or suspension compo-
nent are further causes of pull. A damaged front tire
(bruised, ply separation) can also cause pull.
A common and frequently misdiagnosed pull condi-
tion is where direction of pull changes after a few
stops. The cause is a combination of brake drag fol-
lowed 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 DRAG OR PULL
Rear drag or pull may be caused by improperly
adjusted park brake shoes or seized parking brake
cables, contaminated lining, bent or binding shoes or
improperly assembled components. This is particu-
larly true when only one rear wheel is involved.However, when both rear wheels are affected, the
master cylinder or ABS system 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
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 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.
NOTE: Propshaft angle can also cause vibration/
shudder.
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 vibra-
tion and generate shudder during brake operation.
Tire damage such as a severe bruise, cut, ply separa-
tion, low air pressure can cause pull and vibration.
BRAKE NOISES
Some brake noise is common 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.
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 con-
tribute 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 may become so scored that replacement is nec-
essary.
5 - 4 BRAKES - BASEWJ
BRAKES - BASE (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

STANDARD PROCEDURE - DISC ROTOR
MACHINING
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).
NOTE: A hub mounted on-vehicle lathe is recom-
mended. This type of lathe trues the rotor to the vehi-
cles hub/bearing.
The disc brake rotor can be machined if scored or
worn. The lathe must machine both sides of the rotor
simultaneously with dual cutter heads. The rotor
mounting surface must be clean before placing on the
lathe. Equipment capable of machining only one side at
a time may produce a tapered rotor.
CAUTION: Brake rotors that do not meet minimum
thickness specifications before or after machining
must be replaced.
REMOVAL
REMOVAL - FRONT DISC BRAKE ROTOR
NOTE: 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.
(1) Raise and support the vehicle.
(2) Remove wheel and tire assembly.
(3) Remove the caliper anchor bolts (Fig. 64) and
remove the caliper and anchor as an assembly from the
steering knuckle.
(4) Secure caliper anchor assembly to nearby suspen-
sion part with a wire.Do not allow brake hose to
support caliper weight.
(5) Mark the rotor and hub/bearing to maintain orig-
inal orientation. Remove retainers securing rotor to hub
studs.
(6) Remove rotor from hub/bearing.
REMOVAL - REAR DISC BRAKE ROTOR
(1) Raise and support the vehicle.
(2) Remove wheel and tire assembly.
(3) Remove the caliper anchor bolts (Fig. 65).
(4) Remove caliper and anchor as an assembly.(5) Secure caliper anchor assembly to nearby suspen-
sion part with wire.Do not allow brake hose to sup-
port caliper weight.
(6) Remove retainers securing rotor to axle studs.
(7) Remove rotor off axle studs.
Fig. 64 Caliper Anchor Bolts
1 - KNUCKLE
2 - ANCHOR
3 - ANCHOR BOLTS
4 - ROTOR
Fig. 65 Caliper Anchor Bolts
1 - ROTOR
2 - ANCHOR
3 - ANCHOR BOLTS
WJBRAKES - BASE 5 - 33
ROTORS (Continued)
2002 WJ Service Manual
Publication No. 81-370-02064
02WJ5-33 June, 2002

ELECTRIC BRAKE
DESCRIPTION
The electronic brake distribution (EBD) functions
like a rear proportioning valve. The EBD system uses
the ABS system 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 outlet valves located in the HCU.
OPERATION
Upon entry into EBD the inlet valve for the rear
brake circuit is switched on so that the fluid supply
from 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
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. This will continue until the required slip dif-
ference is obtained. At the end of EBD braking (no
brake application) the fluid in the LPA drains back to
the master cylinder by switching on the outlet valve
and draining through the inlet valve check valve. At
the same time the inlet valve is switched on to pre-
vent a hydraulic short circiut in case of another
brake application.
The EBD will remain functional during many ABS
fault modes. If the red and amber warning lamps are
illuminated the EBD may have a fault.
FRONT WHEEL SPEED
SENSOR
DESCRIPTION
A wheel speed sensor is used at each wheel. The
front sensors are mounted to the steering knuckles.
The rear sensors are mounted at the outboard end of
the axle. Tone wheels are mounted to the outboard
ends of the front and rear axle shafts. The gear type
tone wheel serves as the trigger mechanism for each
sensor.
OPERATION
The sensors convert wheel speed into a small digi-
tal signal. The CAB sends 12 volts to the sensors.
The sensor has an internal magneto resistance
bridge that alters the voltage and amperage of the
signal circuit. This voltage and amperage is changed
by magnetic induction when the toothed tone wheel
passes the wheel speed sensor. This digital signal issent to the CAB. The CAB measures the voltage and
amperage of the digital signal for each wheel.
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the front wheel sensor mounting bolt
(Fig. 1).
(3) Remove the sensor from the steering knuckle.
(4) Disengage the sensor wire from the brackets
(Fig. 1)on the steering knuckle.
(5) Disconnect the sensor from the sensor harness
(Fig. 2)and (Fig. 3).
(6) Remove the sensor and wire.
INSTALLATION
(1) Install the sensor on the steering knuckle.
(2) Apply Mopar Lock N' Seal or Loctitet242 to
the sensor mounting bolt. Use new sensor bolt if orig-
inal bolt is worn or damaged.
(3) Install the sensor mounting bolt and tighten
bolt to 12-14 N´m (106-124 in. lbs.).
(4) Engage the grommets on the sensor wire to the
steering knuckle brackets.
(5) Connect the sensor wire to the harness connec-
tor.
(6) Check the sensor wire routing. Be sure the
wire is clear of all chassis components and is not
twisted or kinked at any spot.
(7) Remove the support and lower vehicle.
Fig. 1 Sensor Location
1 - BRACKET
2 - BRACKET
3 - WHEEL SPEED SENSOR
4 - MOUNTING BOLT
WJBRAKES - ABS 5 - 43

G-SWITCH
DESCRIPTION
The G-switch (Fig. 4) is located under the rear
seat. The switch has directional arrow and must be
mounted with the arrow pointing towards the front
of the vehicle.
OPERATION
The switch is monitored by the CAB at all times.
The switch contains three mercury switches which
monitor vehicle deceleration rates (G-force). Sudden
changes in deceleration rates trigger the switch,
sending a signal to the CAB.
REMOVAL
(1) Fold the rear seat bottom assembly up for
access to the switch.
(2) Lift up the carpeting and disconnect the switch
harness (Fig. 5).
(3) Remove the switch mounting bolts and remove
the switch.
INSTALLATION
CAUTION: The mercury switch (inside the
G-Switch), will not function properly if the switch is
installed incorrectly. Verify that the switch locating
arrow is pointing to the front of the vehicle (Fig. 6).
(1) Note the position of the locating arrow on the
switch. Position the switch so the arrow faces for-
ward.
(2) Install the switch and tighten the mounting
bolts to 5.6 N´m (50 in. lbs.).
Fig. 2 Left Sensor Connector
1 - LEFT FRONT WHEEL SPEED SENSOR CONNECTOR
2 - ENGINE EXHAUST PIPE
3 - LEFT FRONT FRAME RAIL
4 - FRONT DRIVESHAFT
Fig. 3 Right Sensor Connector
1 - RIGHT FRONT WHEEL SPEED SENSOR CONNECTOR
2 - ENGINE EXHAUST Y-PIPE
3 - RIGHT FRONT FRAME RAIL
4 - RIGHT LOWER SUSPENSION ARM
Fig. 4 G-Switch
1 - SWITCH PART NUMBER
2 - ARROW INDICATES FRONT OF SWITCH FOR PROPER
MOUNTING
5 - 44 BRAKES - ABSWJ
FRONT WHEEL SPEED SENSOR (Continued)

(3) Connect the harness to the switch. Be sure the
harness connector is firmly seated.
(4) Place the carpet in position and fold the rear
seat back down.
REAR WHEEL SPEED SENSOR
DESCRIPTION
A wheel speed sensor is used at each wheel. The
front sensors are mounted to the steering knuckles.The rear sensors are mounted at the outboard end of
the axle. Tone wheels are mounted to the outboard
ends of the front and rear axle shafts. The gear type
tone wheel serves as the trigger mechanism for each
sensor.
OPERATION
The sensors convert wheel speed into a small digi-
tal signal. The CAB sends 12 volts to the sensors.
The sensor has an internal magneto resistance
bridge that alters the voltage and amperage of the
signal circuit. This voltage and amperage is changed
by magnetic induction when the toothed tone wheel
passes the wheel speed sensor. This digital signal is
sent to the CAB. The CAB measures the voltage and
amperage of the digital signal for each wheel.
REMOVAL
(1) Raise and fold the rear seat forward. Then
move the carpeting aside for access to the rear sensor
connectors.
(2) Disconnect the rear sensor wire at the harness
connectors (Fig. 7).
(3) Push the sensor wires and grommets through
the floorpan holes.
(4) Raise and support the vehicle.
(5) Disengage the sensor wire from the axle and
the chassis brackets and from the brake line retain-
ers.
(6) Remove the sensor mounting bolt from the rear
brake backing plate. (Fig. 8).
(7) Remove the sensor from the backing plate.
Fig. 5 G-Switch Mounting
1 - MOUNTING BOLTS
2 - CONNECTOR
3 - G-SWITCH
Fig. 6 G-Switch
1 - SWITCH PART NUMBER
2 - ARROW INDICATES FRONT OF SWITCH FOR PROPER
MOUNTING
Fig. 7 Rear Sensor Connector
1 - RIGHT REAR WHEEL SPEED SENSOR CONNECTOR
2 - LEFT REAR WHEEL SPEED SENSOR CONNECTOR
3 - G-SWITCH SENSOR
4 - PARKING BRAKE CABLES
WJBRAKES - ABS 5 - 45
G-SWITCH (Continued)