2003 JEEP GRAND CHEROKEE front brake calipers

(9) Remove piston seals from caliper (Fig. 30) and
discard.
CAUTION: Do not scratch piston bore while remov-
ing the seals.
(10) Remove caliper slide pin bushings (Fig. 31).
(11) Remove caliper bleed screw.
DISASSEMBLY - REAR DISC BRAKE CALIPER
(1) Drain brake fluid out of caliper.
(2) Take a piece of wood and pad it with one-inch
thickness of shop towels. Place this piece in the out-
board shoe side of the caliper in front of the piston.This will cushion and protect caliper piston during
removal (Fig. 32).
(3) To remove caliper piston directshort bursts
of low pressure airwith a blow gun through the
caliper brake hose port (Fig. 33). Use only enough air
pressure to ease the piston out.
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 MAY RESULT
IN PERSONAL INJURY.
Fig. 30 Piston Seal
1 - CALIPER
2 - PISTON BORE
3 - PISTON SEAL
Fig. 31 Caliper Slide Pin Bushings
1 - CALIPER
2 - BUSHING
3 - CALIPER SLIDE PIN
Fig. 32 Padding Caliper Interior
1 - SHOP TOWELS OR CLOTHS
2 - CALIPER
Fig. 33 Caliper Piston Removal
1 - CALIPER PISTON
2 - AIR GUN
3 - PADDING MATERIAL
5 - 18 BRAKES - BASEWJ
DISC BRAKE CALIPERS (Continued)

ASSEMBLY
ASSEMBLY - FRONT DISC BRAKE CALIPER
CAUTION: Dirt, oil, and solvents can damage cali-
per seals. Insure assembly area is clean and dry.
(1) Lubricate caliper pistons, piston seals and pis-
ton bores with clean brake fluid.
(2) Install new piston seals into seal groove with
finger (Fig. 38).
NOTE: Verify seal is fully seated and not twisted.(3) Install new dust boot on caliper piston and seat
boot lip into piston groove (Fig. 39).
(4) Stretch boot rearward to straighten boot folds,
then move boot forward until folds snap into place.
(5) Install piston into caliper bore and press piston
down to the bottom of the caliper bore by hand or
with hammer handle (Fig. 40).
Fig. 37 Polishing Piston Bore
1 - SPECIAL HONE
2 - CALIPER
3 - PISTON BORE
Fig. 38 Piston Seal
1 - CALIPER
2 - PISTON BORE
3 - PISTON SEAL
Fig. 39 Dust Boot On Piston
1 - PISTON
2 - DUST BOOT
Fig. 40 Caliper Piston Installation
1 - CALIPER
2 - DUST BOOT
3 - PISTON
5 - 20 BRAKES - BASEWJ
DISC BRAKE CALIPERS (Continued)

(6) Seat dust boot in caliper with Installer 8280
and Handle C-4171 (Fig. 45).
(7) Install caliper slide pin bushings into the cali-
per (Fig. 46).
(8) Install caliper bleed screw.
INSTALLATION
INSTALLATION - FRONT DISC BRAKE CALIPER
(1) Install the inboard brake shoe (Fig. 22).
(2) Lubricate the slide pins and slide pin bushings
with Dow Corningtgrease G807 or the grease pro-
vided with the caliper.
(3) Install the caliper on the anchor.(4) Install the caliper slide pin and tighten to
29-41 N´m (21-30 ft. lbs.).
(5) Install the caliper slide pin bushing caps.
(6) Install the caliper support spring in the top
end of the caliper and under the anchor. Then install
other end into the lower caliper hole. Hold the spring
into the caliper hole with your thumb while prying
the end of the spring out and down under the anchor
with a screw drive.
(7) Install brake hose to caliper withnew gasket
washersand tighten banjo bolt to 31 N´m (23 ft.
lbs.).
CAUTION: Verify brake hose is not twisted or
kinked before tightening banjo bolt.
(8) Fill and bleed brake system.
(9) Install wheel and tire assemblies.
(10) Remove supports and lower vehicle.
(11) Verify brake fluid level.
INSTALLATION - REAR DISC BRAKE CALIPER
(1) Install the inboard brake shoe (Fig. 26).
(2) Lubricate the slide pins and slide pin bushings
with Dow Corningtgrease G807 or the grease pro-
vided with the caliper.
(3) Install the caliper on the anchor.
(4) Install the caliper slide pin and tighten to
29-41 N´m (21-30 ft. lbs.).
(5) Install the caliper slide pin caps.
(6) Install the caliper support spring in the top
end of the caliper and under the anchor. Then install
other end into the lower caliper hole. Hold the spring
into the caliper hole with your thumb while prying
the end of the spring out and down under the anchor
with a screw drive.
CAUTION: Verify brake hose is not twisted or
kinked before tightening fitting bolt.
(7) Install brake hose to caliper with anewgasket
washers and tighten banjo bolt to 31 N´m (23 ft. lbs.).
(8) Fill and bleed brake system.
(9) Install wheel and tire assemblies.
(10) Remove supports and lower vehicle.
FLUID
DIAGNOSIS AND TESTING - BRAKE FLUID
CONTAMINATION
Indications of fluid contamination are swollen or
deteriorated rubber parts.
Swollen rubber parts indicate the presence of
petroleum in the brake fluid.
To test for contamination, put a small amount of
drained brake fluid in clear glass jar. If fluid sepa-
Fig. 45 Piston Dust Boot Installation
1 - HANDLE
2 - INSTALLER
3 - DUST BOOT
Fig. 46 Slide Pin And Bushing
1 - CALIPER SLIDE PIN
2 - BUSHING
5 - 22 BRAKES - BASEWJ
DISC BRAKE CALIPERS (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

(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)

(3) Push the cables into the upper suspension arm
brackets.
(4) Install the cable retainer bolts to the rear
spring pads.
(5) Install the ABS sensor wiring harness to the
rear brake cables.
(6) Install the rotors, caliper anchors and brake
calipers.
(7) Install the wheel and tire assemblies.
(8) Remove support and lower the vehicle.
(9) Engage the cable ends into the parking brake
equalizer.
(10) Pull on the lever to release the lock out
spring.
(11) Install center console, (Refer to 23 - BODY/IN-
TERIOR/FLOOR CONSOLE - INSTALLATION).
(12) Fold down the rear carpet cover and rear seat.
(13) Verify parking brake operation.
LEVER
REMOVAL
(1) Remove center console,(Refer to 23 - BODY/IN-
TERIOR/FLOOR CONSOLE - REMOVAL).
(2) Lift up rear seat and carpet covering the park-
ing brake cables.
(3) Place a screw driver through the front cable
eyelet (Fig. 77) and pry back on the front cable.(4) Have an assistant pry down the lock out spring
through the hole in the side of the park brake lever
(Fig. 78) with a small screw driver. Then slowly
release the front cable.
NOTE: Their should be slack in the cable if the lock
out spring is engaged.
(5) Disconnect parking brake switch wiring con-
nector.
(6) Disengage front cable end from parking brake
lever.
(7) Compress the cable retainer with a 13 mm
wrench (Fig. 79) and remove the cable from the park-
ing brake lever bracket.
Fig. 77 FRONT CABLE
1 - REAR CABLES
2 - FRONT CABLE EYELET
3 - FRONT CABLE
4 - EQUALIZER
Fig. 78 Lock Out Spring
1 - LOCK OUT SPRING
Fig. 79 Parking Brake Lever Bracket
1 - FRONT CABLE
2 - WRENCH
5 - 38 BRAKES - BASEWJ
CABLES (Continued)