2002 JEEP LIBERTY service

(6) Install adjuster locks on the bearing caps.
(7) Install axle shafts.
(8) Apply a bead of red Mopar silicone rubber axle
sealant or equivalent to the housing cover (Fig. 33).
CAUTION: If cover is not installed within 3 to 5 min-
utes, the cover must be cleaned and new RTV
applied or adhesion quality will be compromised.
(9) Install cover and tighten bolts in a criss-cross
pattern to 41 N´m (30 ft. lbs.).
(10) Fill differential with gear lubricant to bottom
of the fill plug hole.
(11) Install the fill hole plug.
(12) Install wheel and tire assemblies.
(13) Remove support and lower vehicle.
(14) Trac-loktdifferential equipped vehicles should
be road tested by making 10 to 12 slow figure-eight
turns. This maneuver will pump the lubricant
through the clutch discs to eliminate a possible chat-
ter noise complaint.DIFFERENTIAL - TRAC-LOK
DIAGNOSIS AND TESTING - TRAC-LOKT
The most common problem is a chatter noise when
turning corners. Before removing the unit for repair,
drain, flush and refill the axle with the specified
lubricant. A container of Mopar Trac-loktLubricant
(friction modifier) should be added after repair ser-
vice or during a lubricant change.
After changing the lubricant, drive the vehicle and
make 10 to 12 slow, figure-eight turns. This maneu-
ver will pump lubricant through the clutches. This
will correct the condition in most instances. If the
chatter persists, clutch damage could have occurred.
DIFFERENTIAL TEST
The differential can be tested without removing the
differential case by measuring rotating torque. Make
sure brakes are not dragging during this measure-
ment.
(1) Place blocks in front and rear of both front
wheels.
(2) Raise one rear wheel until it is completely off
the ground.
(3) Engine off, transmission in neutral, and park-
ing brake off.
(4) Remove wheel and bolt Special Tool 6790 or
equivalent tool to studs.
(5) Use torque wrench on special tool to rotate
wheel and read rotating torque (Fig. 34).
(6) If rotating torque is less than 41 N´m (56 ft.
lbs.) or more than 271 N´m (200 ft. lbs.) on either
wheel the unit should be serviced.
Fig. 33 Differential Cover Sealant
1 - SEALANT
2 - DIFFERNTIAL COVER
Fig. 34 ROTATING TORQUE TEST
1 - SPECIAL TOOL WITH BOLT IN CENTER HOLE
2 - TORQUE WRENCH
3 - 106 REAR AXLE-81/4KJ
DIFFERENTIAL (Continued)

DISASSEMBLY
(1) Clamp side gear Fixture 8138 in a vise and set
differential case on the fixture (Fig. 35).
(2) Remove ring gear if the ring gear is to be
replaced. The Trac-loktdifferential can be serviced
with the ring gear installed.
(3) Remove pinion gear mate shaft lock screw.
(4) Remove pinion gear mate shaft with a drift and
hammer.
(5) Install Discs 8140 without threaded hole in the
lower side gear (Fig. 36).
(6) Install Disc 8140 with threaded hole in the
upper side gear. Thread Forcing Screw 6960-4
through the upper disc until it becomes centered in
lower disc.
(7) Insert a screw driver in slot of upper disc (Fig.
37) to prevent disc from turning.
Fig. 36 LOWER DISC
1 - LOWER SIDE GEAR
2 - DIFFERENTIAL CASE
3 - DISC
Fig. 37 TRAK-LOCTTOOLS
1 - SOCKET
2 - SLOT IN DISC
3 - SCREWDRIVER
4 - LOWER DISC
5 - THREADED ROD
6 - UPPER DISC
Fig. 35 DIFFERENTIAL CASE FIXTURE
1 - FIXTURE
2 - VISE
3 - DIFFERENTIAL
KJREAR AXLE - 8 1/4 3 - 107
DIFFERENTIAL - TRAC-LOK (Continued)

(14) Install pinion gear mate shaft and align holes
in shaft and case.
(15) Install pinion mate shaft lock screw finger
tight to hold shaft during differential installation.
(16) Lubricate all differential components with
hypoid gear lubricant.
DIFFERENTIAL CASE
BEARINGS
REMOVAL
(1) Remove differential case from axle.
(2) Remove differential bearings from the case
with Puller/Press C-293-PA and Adapters C-293-48
and Plug SP-3289 (Fig. 45).
INSTALLATION
(1) Install differential side bearings with Installer
C-4340 and Handle C-4171 (Fig. 46).
(2) Install differential case in axle.
PINION GEAR/RING GEAR/
TONE RING
REMOVAL
CAUTION: The ring and pinion gears are serviced in
a matched set. Never replace one gear without
replacing the other matched gear.
(1) Mark pinion yoke and propeller shaft for
installation reference.
(2) Remove propeller shaft from pinion yoke and
tie propeller shaft to underbody.
(3) Remove differential from axle housing.
(4) Place differential case in a vise with soft metal
jaw (Fig. 47).
(5) Remove bolts holding ring gear to differential
case.
(6) Drive ring gear from the differential case with
a rawhide hammer.
Fig. 44 CLUTCH PACK AND UPPER SIDE GEAR
1 - SIDE GEAR AND CLUTCH PACK
2 - DIFFERENTIAL CASE
3 - LOWER DISC
Fig. 45 Differential Bearing Puller
1 - PULLER
2 - ADAPTERS
3 - BEARING
4 - DIFFERENTIAL
5 - PLUG
3 - 110 REAR AXLE-81/4KJ
DIFFERENTIAL - TRAC-LOK (Continued)

BRAKE LINES
DESCRIPTION
Flexible rubber hose is used at both front brakes
and at the rear axle junction block. Double walled
steel tubing is used to connect the master cylinder to
the major hydraulic braking components and then to
the flexible rubber hoses. Double inverted style and
ISO style flares are used on the brake lines.
DIAGNOSIS AND TESTING - BRAKE LINE AND
HOSES
Flexible rubber hose is used at both front brakes
and at the rear axle junction block. Inspect the hoses
whenever the brake system is serviced, at every
engine oil change, or whenever the vehicle is in for
service.
Inspect the hoses for surface cracking, scuffing, or
worn spots. Replace any brake hose immediately if
the fabric casing of the hose is exposed due to cracks
or abrasions.
Also check brake hose installation. Faulty installa-
tion can result in kinked, twisted hoses, or contact
with the wheels and tires or other chassis compo-
nents. All of these conditions can lead to scuffing,
cracking and eventual failure.
The steel brake lines should be inspected periodi-
cally for evidence of corrosion, twists, kinks, leaks, or
other damage. Heavily corroded lines will eventually
rust through causing leaks. In any case, corroded or
damaged brake lines should be replaced.
Factory replacement brake lines and hoses are rec-
ommended to ensure quality, correct length and supe-
rior fatigue life. Care should be taken to make sure
that brake line and hose mating surfaces are clean
and free from nicks and burrs. Also remember that
right and left brake hoses are not interchangeable.
Use new copper seal washers at all caliper connec-
tions. Be sure brake line connections are properly
made (not cross threaded) and tightened to recom-
mended torque.
STANDARD PROCEDURE
STANDARD PROCEDURE - DOUBLE INVERTED
FLARING
A preformed metal brake tube is recommended and
preferred for all repairs. However, double-wall steel
tube can be used for emergency repair when factory
replacement parts are not readily available.
Special bending tools are needed to avoid kinking
or twisting of metal brake tubes. Special flaring tools
are needed to make a double inverted flare or ISO
flare.(1) Cut off damaged tube with Tubing Cutter.
(2) Ream cut edges of tubing to ensure proper
flare.
(3) Install replacement tube nut on the tube.
(4) Insert tube in flaring tool.
(5) Place gauge form over the end of the tube.
(6) Push tubing through flaring tool jaws until
tube contacts recessed notch in gauge that matches
tube diameter.
(7) Tighten the tool bar on the tube
(8) Insert plug on gauge in the tube. Then swing
compression disc over gauge and center tapered flar-
ing screw in recess of compression disc (Fig. 2).
(9) Tighten tool handle until plug gauge is
squarely seated on jaws of flaring tool. This will start
the inverted flare.
(10) Remove the plug gauge and complete the
inverted flare.
STANDARD PROCEDURE - ISO FLARING
A preformed metal brake tube is recommended and
preferred for all repairs. However, double-wall steel
tube can be used for emergency repair when factory
replacement parts are not readily available.
Special bending tools are needed to avoid kinking
or twisting of metal brake tubes. Special flaring tools
are needed to make a double inverted flare or ISO
flare.
To make a ISO flare use a ISO brake flaring tool or
equivalent.
(1) Cut off damaged tube with Tubing Cutter.
(2) Remove any burrs from the inside of the tube.
(3) Install tube nut on the tube.
Fig. 2 Inverted
5 - 8 BRAKES - BASEKJ

JUNCTION BLOCK
DESCRIPTION
The junction block and a rear brake proportioning
valve. The valve is not repairable and must be
replaced as an assembly if diagnosis indicates this is
necessary.
OPERATION
PROPORTIONING VALVE
The proportioning valve is used to balance front-
rear brake action at high decelerations. The valve
allows normal fluid flow during moderate braking.
The valve only controls fluid flow during high decel-
erations brake stops. If the primary brake hydraulic
circuit cannot build pressure a by-pass feature is
activated allowing full flow and pressure to the rear
brakes.
DIAGNOSIS AND TESTING - PROPORTIONING
VALVE
The valve controls fluid flow. If fluid enters the
valve and does not exit the valve the combination
valve must be replaced.
REMOVAL
(1) Install prop rod on the brake pedal to keep
pressure on the brake system.
(2) Remove the brake lines from the junction
block.
(3) Remove mounting nuts and bolt and remove
the junction block (Fig. 31).
INSTALLATION
(1) Install the junction block on the mounting
studs.
(2) Install mounting nuts and bolt. Tighten to 14
N´m (125 in. lbs.).
(3) Install brake lines to the junction block and
tighten to 20 N´m (180 in. lbs.).
(4) Bleed ABS brake system (Refer to 5 - BRAKES
- STANDARD PROCEDURE).
PEDAL
DESCRIPTION
A suspended-type brake pedal is used, the pedal
pivots on a shaft mounted in the steering coloumn
support bracket. The bracket is attached to the dash
panel. The unit is serviced as an assembly, except for
the pedal pad.
OPERATION
The brake pedal is attached to the booster push
rod. When the pedal is depressed, the primary
booster push rod is depressed which move the booster
secondary rod. The booster secondary rod depress the
master cylinder piston.
REMOVAL
(1) Remove the knee blocker under the steering
column,(Refer to 23 - BODY/INSTRUMENT PANEL/
KNEE BLOCKER - REMOVAL).
(2) Remove the retainer clip securing the booster
push rod to pedal (Fig. 32).
(3) Remove the brake lamp switch,(Refer to 8 -
ELECTRICAL/LAMPS/LIGHTING - EXTERIOR/
BRAKE LAMP SWITCH - REMOVAL).
(4) Remove the nuts securing the pedal to the col-
umn bracket.
(5) Remove the pedal from the vehicle.
INSTALLATION
(1) Install the pedal into the vehicle.
(2) Install the nuts securing the pedal to the col-
umn bracket.
(3) Tighten the nuts to 22.6 N´m (200 in. lbs.).
(4) Lubricate the brake pedal pin and bushings
with Mopar multi-mileage grease.
(5) Install the booster push rod on the pedal pin
and install a new retainer clip (Fig. 32).
(6) Install the brake lamp switch,(Refer to 8 -
ELECTRICAL/LAMPS/LIGHTING - EXTERIOR/
BRAKE LAMP SWITCH - INSTALLATION).
(7) Install the knee blocker,(Refer to 23 - BODY/
INSTRUMENT PANEL/KNEE BLOCKER - INSTAL-
LATION).
Fig. 31 JUNCTION BLOCK
1 - JUNCTION BLOCK
2 - MOUNTING NUT
5 - 20 BRAKES - BASEKJ

POWER BRAKE BOOSTER
DESCRIPTION
The booster assembly consists of a housing divided
into separate chambers by two internal diaphragms.
The outer edge of each diaphragm is attached to the
booster housing. The diaphragms are connected to
the booster primary push rod.
Two push rods are used in the booster. The pri-
mary push rod connects the booster to the brake
pedal. The secondary push rod connects the booster
to the master cylinder to stroke the cylinder pistons.
OPERATION
The atmospheric inlet valve is opened and closed
by the primary push rod. Booster vacuum supply is
through a hose attached to an intake manifold fitting
at one end and to the booster check valve at the
other. The vacuum check valve in the booster housing
is a one-way device that prevents vacuum leak back.
Power assist is generated by utilizing the pressure
differential between normal atmospheric pressure
and a vacuum. The vacuum needed for booster oper-
ation is taken directly from the engine intake mani-
fold. The entry point for atmospheric pressure is
through a filter and inlet valve at the rear of the
housing (Fig. 33).
The chamber areas forward of the booster dia-
phragms are exposed to vacuum from the intake
manifold. The chamber areas to the rear of the dia-
phragms, are exposed to normal atmospheric pres-
sure of 101.3 kilopascals (14.7 pounds/square in.).Brake pedal application causes the primary push
rod to open the atmospheric inlet valve. This exposes
the area behind the diaphragms to atmospheric pres-
sure. The resulting pressure differential provides the
extra apply force for power assist.
The booster check valve, check valve grommet and
booster seals are serviceable.
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. 34).
(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.
Fig. 32 BOOSTER PUSH ROD
1 - MASTER CYLINDER ASSEMBLY
2 - BRAKE BOOSTER
3 - CLIP
4 - BRAKE PEDAL
5 - BOOSTER ROD
KJBRAKES - BASE 5 - 21
PEDAL (Continued)

(4) Tighten booster mounting nuts to 22.6 N´m
(200 ft. lbs.).
(5) Install the knee blocker,(Refer to 23 - BODY/
INSTRUMENT PANEL/KNEE BLOCKER - INSTAL-
LATION).
(6) If original master cylinder is being installed,
check condition of seal at rear of master cylinder.
Replace seal if cut, or torn.
(7) Clean cylinder mounting surface of brake
booster. Use shop towel wetted with brake cleaner for
this purpose. Dirt, grease, or similar materials will
prevent proper cylinder seating and could result in
vacuum leak.
(8) Align and install master cylinder on the
booster studs. Install mounting nuts and tighten to
22.6 N´m (200 in. lbs.).
(9) Connect vacuum hose to booster check valve.
(10) Remount the HCU. Tighten bracket mounting
nuts to 22.6 N´m (200 in. lbs.).
(11) Connect and secure the brake lines to HCU or
junction block and master cylinder. Start all brake
line fittings by hand to avoid cross threading.
(12) Connect the wire to fluid level switch at the
bottom of the reservoir.
(13) Fill and bleed base brake system,(Refer to 5 -
BRAKES - STANDARD PROCEDURE).
(14) Verify proper brake operation before moving
vehicle.
MASTER CYLINDER
DESCRIPTION
The master cylinder has a removable nylon reser-
voir. The cylinder body is made of aluminum and
contains a primary and secondary piston assembly.
The cylinder body including the piston assemblies
are not serviceable. If diagnosis indicates an internal
problem with the cylinder body, it must be replaced
as an assembly. The reservoir and grommets are the
only replaceable parts on the master cylinder.
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.
The master cylinder reservoir stores reserve brake
fluid for the hydraulic brake circuits.
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. 38).
(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. 39).
(5) Vacuum should hold steady. If gauge on pump
indicates vacuum loss, check valve is faulty and
should be replaced.
STANDARD PROCEDURE - MASTER CYLINDER
BLEEDING
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.
5 - 24 BRAKES - BASEKJ
POWER BRAKE BOOSTER (Continued)

(2) Attach bleed tubes to cylinder outlet ports.
Then position each tube end into reservoir (Fig. 40).
(3) Fill reservoir with fresh brake fluid.
(4) Press cylinder pistons inward with wood dowel.
Then release pistons and allow them to return underspring pressure. Continue bleeding operations until
air bubbles are no longer visible in fluid.
REMOVAL
(1) Siphon and drain the fluid from the reservoir.
(2) Remove the brake lines at the master cylinder.
(3) Disconnect the fluid level electrical connector
from the reservoir.
(4) Remove mounting nuts from the master cylin-
der.
(5) Remove master cylinder.
(6) Remove cylinder cover and drain the rest of the
fluid.
(7) If master cylinder reservoir requires service-
,(Refer to 5 - BRAKES/HYDRAULIC/MECHANICAL/
FLUID RESERVOIR - REMOVAL). (Fig. 41)
INSTALLATION
NOTE: If master cylinder is replaced, bleed cylinder
before installation.
(1) Clean cylinder mounting surface of brake
booster.
(2) Install master cylinder onto brake booster
studs.
(3) Install mounting nuts and tighten to 25 N´m
(220 in. lbs.).
(4) Connect the brake lines to the master cylinder
and tighten to 20 N´m (180 in. lbs.).
(5) Connect fluid level electrical connector to the
reservoir.
(6) Fill and bleed base brake system,(Refer to 5 -
BRAKES - STANDARD PROCEDURE).
Fig. 38 Typical Booster Vacuum Test Connections
1 - TEE FITTING
2 - SHORT CONNECTING HOSE
3 - CHECK VALVE
4 - CHECK VALVE HOSE
5 - CLAMP TOOL
6 - INTAKE MANIFOLD
7 - VACUUM GAUGE
Fig. 39 TYPICAL - VACUUM CHECK VALVE AND
SEAL
1 - BOOSTER CHECK VALVE
2 - APPLY TEST VACUUM HERE
3 - VALVE SEAL
Fig. 40 MASTER - TYPICAL
1 - BLEEDING TUBES
2 - RESERVOIR
KJBRAKES - BASE 5 - 25
MASTER CYLINDER (Continued)