piston removal JEEP LIBERTY 2002 KJ / 1.G Workshop Manual

DIAGNOSIS AND TESTING - MASTER
CYLINDER/POWER BOOSTER...........21
REMOVAL.............................22
INSTALLATION.........................23
MASTER CYLINDER
DESCRIPTION.........................24
OPERATION...........................24
DIAGNOSIS AND TESTING - MASTER
CYLINDER/POWER BOOSTER...........24
STANDARD PROCEDURE - MASTER
CYLINDER BLEEDING..................24
REMOVAL.............................25
INSTALLATION.........................25
FLUID RESERVOIR
REMOVAL.............................26
INSTALLATION.........................26
FLUID
DIAGNOSIS AND TESTING - BRAKE FLUID
CONTAMINATION.....................26
STANDARD PROCEDURES - MASTER
CYLINDER FLUID LEVEL................26
SPECIFICATIONS
BRAKE FLUID........................27
DRUM
DIAGNOSIS AND TESTING - BRAKE DRUM . . . 27
STANDARD PROCEDURES - BRAKE DRUM
MACHINING..........................27SUPPORT PLATE
REMOVAL
REMOVAL - 198 RBI AXLE..............27
REMOVAL - 8 1/4 AXLE.................27
INSTALLATION
INSTALLATION - 198 RBI AXLE...........28
INSTALLATION - 8 1/4 AXLE.............28
WHEEL CYLINDERS
REMOVAL.............................28
DISASSEMBLY.........................28
CLEANING............................28
INSPECTION..........................29
ASSEMBLY............................29
INSTALLATION.........................29
PARKING BRAKE
DESCRIPTION.........................29
OPERATION...........................29
ADJUSTMENTS
ADJUSTMENT - LOCK OUT.............30
CABLES
REMOVAL.............................30
INSTALLATION.........................30
LEVER
REMOVAL.............................31
INSTALLATION.........................31
BRAKES - BASE
DESCRIPTION
Power assist front disc and rear drum brakes are
standard equipment. Disc brake components consist
of single piston calipers and ventilated rotors. Rear
drum brakes are dual shoe units with cast brake
drums.
The parking brake mechanism is lever and cable
operated. The cables are attached to levers on the
rear drum brake secondary shoes. The parking
brakes are operated by a hand lever.
A dual diaphragm vacuum power brake booster is
used for all applications. All models have an alumi-
num master cylinder with plastic reservoir.
All models are equipped with a combination valve.
The valve contains a pressure differential valve and
switch and a fixed rate rear proportioning valve.
Factory brake lining on all models consists of an
organic base material combined with metallic parti-
cles. The original equipment linings do not contain
asbestos.
WARNING
WARNING: DUST AND DIRT ACCUMULATING ON
BRAKE PARTS DURING NORMAL USE MAY CON-
TAIN ASBESTOS FIBERS FROM AFTERMARKET
LININGS. BREATHING EXCESSIVE CONCENTRA-
TIONS OF ASBESTOS FIBERS CAN CAUSE SERI-
OUS BODILY HARM. EXERCISE CARE WHEN
SERVICING BRAKE PARTS. DO NOT CLEAN
BRAKE PARTS WITH COMPRESSED AIR OR BY
DRY BRUSHING. USE A VACUUM CLEANER SPE-
CIFICALLY DESIGNED FOR THE REMOVAL OF
ASBESTOS FIBERS FROM BRAKE COMPONENTS.
IF A SUITABLE VACUUM CLEANER IS NOT AVAIL-
ABLE, CLEANING SHOULD BE DONE WITH A
WATER DAMPENED CLOTH. DO NOT SAND, OR
GRIND BRAKE LINING UNLESS EQUIPMENT USED
IS DESIGNED TO CONTAIN THE DUST RESIDUE.
DISPOSE OF ALL RESIDUE CONTAINING ASBES-
TOS FIBERS IN SEALED BAGS OR CONTAINERS
TO MINIMIZE EXPOSURE TO YOURSELF AND OTH-
ERS. FOLLOW PRACTICES PRESCRIBED BY THE
OCCUPATIONAL SAFETY AND HEALTH ADMINIS-
TRATION AND THE ENVIRONMENTAL PROTECTION
AGENCY FOR THE HANDLING, PROCESSING, AND
DISPOSITION OF DUST OR DEBRIS THAT MAY
CONTAIN ASBESTOS FIBERS.
5 - 2 BRAKES - BASEKJ

OPERATION - REAR DRUM BRAKE
When the brake pedal is depressed hydraulic pres-
sure pushes the rear brake wheel cylinder pistons
outward. The wheel cylinder push rods then push the
brake shoes outward against the brake drum. When
the brake pedal is released return springs attached
to the brake shoes pull the shoes back to there orig-
inal position (Fig. 9).
REMOVAL
REMOVAL - FRONT BRAKE PADS
(1) Raise and support the vehicle.
(2) Remove the front wheel and tire assembly.
(3) Drain a small amount of fluid from the master
cylinder brake reservoir with acleansuction gun.(4) Bottom the caliper pistons into the caliper by
prying the caliper over.
(5) Remove the caliper mounting bolts.
(6) Remove the disc brake caliper from the mount.
CAUTION: Never allow the disc brake caliper to
hang from the brake hose. Damage to the brake
hose will result. Provide a suitable support to hang
the caliper securely.
(7) Remove the inboard and outboard pads.
REMOVAL - DRUM BRAKE SHOES
(1) Raise the vehicle and remove the rear wheels.
(2) Remove and discard the spring nuts securing
drums to wheel studs.
(3) Remove the brake drums. If drums prove diffi-
cult to remove, retract brake shoes. Remove the
access hole plug at the rear of backing plate and
back off adjuster screw with brake tool and screw-
driver.
(4) Clean the individual brake components, includ-
ing the support plate and wheel cylinder exterior,
with a find mist of water. Then wipe the brake com-
ponents clean with a dampened cloth.
(5) Remove the primary and secondary return
springs from anchor pin with the brake spring pliers.
(6) Remove the U-clip and washer securing
adjuster cable to the parking brake lever.
(7) Remove the hold-down springs, retainers and
pins with standard retaining spring tool.
(8) Remove the parking brake strut and cable
guide.
(9) Remove the adjuster lever, adjuster screw and
spring.
(10) Remove the adjuster cable.
(11) Remove the brake shoes.
(12) Disconnect the cable from the parking brake
lever and remove the lever ( if needed).
INSTALLATION
INSTALLATION - FRONT BRAKE PADS
(1) Install the inboard and outboard pads.
(2) Install the caliper (Refer to 5 - BRAKES/HY-
DRAULIC/MECHANICAL/DISC BRAKE CALIPERS
- INSTALLATION).
(3) Install the tire and wheel assembly. (Refer to
22 - TIRES/WHEELS/WHEELS - STANDARD PRO-
CEDURE).
INSTALLATION - DRUM BRAKE SHOES
Bonded linings should be replaced when worn to a
thickness of 1.6 mm (1/16 in.).
Fig. 9 BRAKE COMPONENTS
1 - SECONDARY SHOE
2 - SHOE GUIDE PLATE
3 - PRIMARY SHOE
4 - HORSE SHOE RETAINING CLIP
5 - PRIMARY RETURN SPRING
6 - PARK BRAKE STRUT
7 - HOLD DOWN SPRING AND RETAINERS
8 - SHOE RETURN SPRING
9 - ADJUSTER SCREW ASSEMBLY
10 - ADJUSTER LEVER
11 - ADJUSTER CABLE
12 - SECONDARY RETURN SPRING
13 - CABLE GUIDE
14 - WHEEL CYLINDER
15 - PARK BRAKE STRUT AND SPRING
16 - SUPPORT PLATE
KJBRAKES - BASE 5 - 11
BRAKE PADS / SHOES (Continued)

OPERATION
When the brakes are applied fluid pressure is
exerted against the caliper piston. The fluid pressure
is exerted equally and in all directions. This means
pressure exerted against the caliper piston and
within the caliper bore will be equal (Fig. 14).
Fluid pressure applied to the piston is transmitted
directly to the inboard brake shoe. This forces the
shoe lining against the inner surface of the disc
brake rotor. At the same time, fluid pressure within
the piston bore forces the caliper to slide inward on
the mounting bolts. This action brings the outboard
brake shoe lining into contact with the outer surface
of the disc brake rotor.
In summary, fluid pressure acting simultaneously
on both piston and caliper, produces a strong clamp-
ing action. When sufficient force is applied, friction
will attempt to stop the rotors from turning and
bring the vehicle to a stop.
Application and release of the brake pedal gener-
ates only a very slight movement of the caliper and
piston. Upon release of the pedal, the caliper and pis-
ton return to a rest position. The brake shoes do not
retract an appreciable distance from the rotor. In
fact, clearance is usually at, or close to zero. The rea-
sons for this are to keep road debris from gettingbetween the rotor and lining and in wiping the rotor
surface clear each revolution.
The caliper piston seal controls the amount of pis-
ton extension needed to compensate for normal lining
wear.
During brake application, the seal is deflected out-
ward by fluid pressure and piston movement (Fig.
15). When the brakes (and fluid pressure) are
released, the seal relaxes and retracts the piston.
The amount of piston retraction is determined by
the amount of seal deflection. Generally the amount
is just enough to maintain contact between the pis-
ton and inboard brake shoe.
REMOVAL
(1) Install prop rod on the brake pedal to keep
pressure on the brake system.
(2) Raise and support vehicle.
(3) Remove front wheel and tire assembly.
(4) Drain small amount of fluid from master cylin-
der brake reservoir with suction gun.
(5) Remove the brake hose banjo bolt if replacing
caliper (Fig. 16).
(6) Remove the caliper mounting slide pin bolts
(Fig. 16).
(7) Remove the caliper from vehicle.
DISASSEMBLY
(1) Remove brake shoes from caliper.
(2) Drain brake fluid out of caliper.
(3) 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. 17).
Fig. 14 Brake Caliper Operation
1 - CALIPER
2 - PISTON
3 - PISTON BORE
4 - SEAL
5 - INBOARD SHOE
6 - OUTBOARD SHOE
Fig. 15 Lining Wear Compensation By Piston Seal
1 - PISTON
2 - CYLINDER BORE
3 - PISTON SEAL BRAKE PRESSURE OFF
4 - CALIPER HOUSING
5 - DUST BOOT
6 - PISTON SEAL BRAKE PRESSURE ON
5 - 14 BRAKES - BASEKJ
DISC BRAKE CALIPERS (Continued)

(4) Remove caliper piston withshort burstsof
low pressure compressed air. Direct air through fluid
inlet port and ease piston out of bore (Fig. 18).
CAUTION: Do not blow the piston out of the bore
with sustained air pressure. This could result in a
cracked piston. Use only enough air pressure to
ease the piston out.
WARNING: NEVER ATTEMPT TO CATCH THE PIS-
TON AS IT LEAVES THE BORE. THIS MAY RESULT
IN PERSONAL INJURY.(5) Remove caliper piston dust boot with suitable
pry tool (Fig. 19).
(6) Remove caliper piston seal with wood or plastic
tool (Fig. 20). Do not use metal tools as they will
scratch piston bore.
(7) Remove caliper mounting bolt bushings and
boots (Fig. 21).
Fig. 16 DISC BRAKE CALIPER
1 - DISC BRAKE CALIPER
2 - CALIPER SLIDE MOUNTING BOLTS
3 - BRAKE HOSE
4 - BANJO BOLT
5 - CALIPER ADAPTER MOUNTING BOLT
Fig. 17 PADDING CALIPER INTERIOR - TYPICAL
1 - SHOP TOWELS OR CLOTHS
2 - CALIPER
Fig. 18 CALIPER PISTON REMOVAL - TYPICAL
1 - AIR GUN
2 - CALIPER PISTON
3 - PADDING MATERIAL
Fig. 19 CALIPER PISTON DUST BOOT REMOVAL -
TYPICAL
1 - COLLAPSE BOOT WITH PUNCH OR SCREWDRIVER
2 - PISTON DUST BOOT
KJBRAKES - BASE 5 - 15
DISC BRAKE CALIPERS (Continued)

CLEANING
Clean the caliper components with clean brake
fluid or brake clean only. Wipe the caliper and piston
dry with lint free towels or use low pressure com-
pressed air.
CAUTION: Do not use gasoline, kerosene, thinner,
or similar solvents. These products may leave a
residue that could damage the piston and seal.
INSPECTION
The piston is made from a phenolic resin (plastic
material) and should be smooth and clean.
The piston must be replaced if cracked or scored.
Do not attempt to restore a scored piston surface by
sanding or polishing.
CAUTION: If the caliper piston is replaced, install
the same type of piston in the caliper. Never inter-
change phenolic resin and steel caliper pistons.The pistons, seals, seal grooves, caliper bore and
piston tolerances are different.
The bore can belightlypolished with a brake
hone to remove very minor surface imperfections
(Fig. 22). The caliper should be replaced if the bore is
severely corroded, rusted, scored, or if polishing
would increase bore diameter more than 0.025 mm
(0.001 inch).
ASSEMBLY
CAUTION: Dirt, oil, and solvents can damage cali-
per seals. Insure assembly area is clean and dry.
(1) Lubricate caliper piston bore, new piston seal
and piston with clean brake fluid.
(2) Lubricate caliper bushings and interior of
bushing boots with silicone grease.
(3) Install bushing boots in caliper, then insert
bushing into boot and push bushing into place (Fig.
23).
(4) Install new piston seal into seal groove with
finger (Fig. 24).
(5) Install new dust boot on caliper piston and seat
boot in piston groove (Fig. 25).
(6) Press piston into caliper bore by hand, use a
turn and push motion to work piston into seal (Fig.
26).
(7) Press caliper piston to bottom of bore.
(8) Seat dust boot in caliper with Installer Tool
C-4842 and Tool Handle C-4171 (Fig. 27).
(9) Replace caliper bleed screw if removed.
Fig. 20 PISTON SEAL REMOVAL - TYPICAL
1 - REMOVE SEAL WITH WOOD PENCIL OR SIMILAR TOOL
2 - PISTON SEAL
Fig. 21 MOUNTING BOLT BUSHING AND BOOT -
TYPICAL
1 - CALIPER SLIDE BUSHING
2 - BOOT
Fig. 22 POLISHING PISTON BORE - TYPICAL
1 - SPECIAL HONE
2 - CALIPER
3 - PISTON BORE
5 - 16 BRAKES - BASEKJ
DISC BRAKE CALIPERS (Continued)

(4) Install the brake hose to the caliper withnew
seal washersand tighten fitting bolt to 31 N´m (23
ft. lbs.).
CAUTION: Verify brake hose is not twisted or
kinked before tightening fitting bolt.
(5) Remove the prop rod from the vehicle.
(6) Bleed the base brake system,(Refer to 5 -
BRAKES - STANDARD PROCEDURE) OR (Refer to
5 - BRAKES - STANDARD PROCEDURE).
(7) Install the wheel and tire assemblies (Refer to
22 - TIRES/WHEELS/WHEELS - STANDARD PRO-
CEDURE).
(8) Remove the supports and lower the vehicle.
(9) Verify a firm pedal before moving the vehicle.
DISC BRAKE CALIPER
ADAPTER
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the front wheel and tire assembly.
(3) Drain a small amount of fluid from master cyl-
inder brake reservoir with acleansuction gun.
(4) Bottom the caliper pistons into the caliper by
prying the caliper over.
(5) Remove the caliper mounting bolts (Fig. 16).
(6) Remove the disc brake caliper from the mount.
CAUTION: Never allow the disc brake caliper to
hang from the brake hose. Damage to the brake
hose will result. Provide a suitable support to hang
the caliper securely.
(7) Remove the inboard and outboard brake pads.
(Refer to 5 - BRAKES/HYDRAULIC/MECHANICAL/
BRAKE PADS/SHOES - REMOVAL).
(8) Remove the caliper adapter mounting bolts
(Fig. 16).
INSTALLATION
(1) Install the caliper adapter mounting bolts.
Tighten the mounting bolts to 135 N´m (100 ft.lbs).
(2) Install the inboard and outboard pads. (Refer
to 5 - BRAKES/HYDRAULIC/MECHANICAL/
BRAKE PADS/SHOES - INSTALLATION).
(3) Install the caliper mounting bolts.
(4) Install the tire and wheel assembly. (Refer to
22 - TIRES/WHEELS/WHEELS - STANDARD PRO-
CEDURE).
ROTORS
DIAGNOSIS AND TESTING - DISC BRAKE
ROTOR
The rotor braking surfaces should not be refinished
unless necessary.
Light surface rust and scale can be removed with a
lathe equipped with dual sanding discs. The rotor
surfaces can be restored by machining in a disc brake
lathe if surface scoring and wear are light.
Replace the rotor under the following conditions:
²severely scored
²tapered
²hard spots
²cracked
²below minimum thickness
ROTOR MINIMUM THICKNESS
Measure rotor thickness at the center of the brake
shoe contact surface. Replace the rotor if worn below
minimum thickness, or if machining would reduce
thickness below the allowable minimum.
Rotor minimum thickness is usually specified on
the rotor hub. The specification is either stamped or
cast into the hub surface.
ROTOR RUNOUT
Check rotor lateral runout with dial indicator
C-3339 (Fig. 28). Excessive lateral runout will cause
brake pedal pulsation and rapid, uneven wear of the
brake shoes. Position the dial indicator plunger
approximately 25.4 mm (1 in.) inward from the rotor
edge. The dial indicator should be positioned in the
center of the rotor surface. Maximum allowable rotor
runout is 0.102 mm (0.004 in.).
ROTOR THICKNESS VARIATION
Variations in rotor thickness will cause pedal pul-
sation, noise and shudder.
Measure rotor thickness at 6 to 12 points around
the rotor face (Fig. 29).
Position the micrometer approximately 25.4 mm (1
in.) from the rotor outer circumference for each mea-
surement.
Thickness should notvaryby more than 0.013 mm
(0.0005 in.) from point-to-point on the rotor. Machine
or replace the rotor if necessary.
5 - 18 BRAKES - BASEKJ
DISC BRAKE CALIPERS (Continued)

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

(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)

(9) Remove the axle shaft, (Refer to 3 - DIFFER-
ENTIAL & DRIVELINE/REAR AXLE - 8 1/4/AXLE
SHAFTS - REMOVAL).
(10) Remove the bolts attaching the support plate
to the axle and remove the support plate (Fig. 43).
INSTALLATION
INSTALLATION - 198 RBI AXLE
(1) Install the support plate on the axle flange.
Tighten 75 N´m (55 ft. lbs.)
(2) Install the axle, bearing and seal into the hous-
ing and tighten the four attaching bolts to 61 N´m
(45 ft. lbs.).
(3) Install the wheel cylinder,(Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/WHEEL
CYLINDERS - INSTALLATION).
(4) Install the brake line in the wheel cylinder.
(5) Install the parking brake cable in the support
plate.
(6) Connect parking brake cable to lever on sec-
ondary shoe and install brake shoes on support plate.
(7) Adjust the brake shoes to the drum with the
brake gauge.
(8) Install the brake drum and wheel and tire
assembly (Refer to 22 - TIRES/WHEELS/WHEELS -
STANDARD PROCEDURE).
(9) Bleed brake system,(Refer to 5 - BRAKES -
STANDARD PROCEDURE) OR (Refer to 5 -
BRAKES - STANDARD PROCEDURE).
INSTALLATION - 8 1/4 AXLE
(1) Install the support plate on the axle flange.
Tighten attaching bolts to 61 N´m (45 ft. lbs.) (Fig.
43).(2) Install the wheel cylinder,(Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/WHEEL
CYLINDERS - INSTALLATION).
(3) Install the brake line in the wheel cylinder and
tighten the line to 14 N´m (124 in.lbs.)..
(4) Remove the brake pedal prop rod.
(5) Install the parking brake cable in the support
plate.
(6) Install the axle shaft, (Refer to 3 - DIFFEREN-
TIAL & DRIVELINE/REAR AXLE - 8 1/4/AXLE
SHAFTS - INSTALLATION).
(7) Connect the parking brake cable to the lever on
the primary shoe and install the brake shoes on the
support plate (Refer to 5 - BRAKES/HYDRAULIC/
MECHANICAL/BRAKE PADS/SHOES - INSTALLA-
TION).
(8) Adjust the brake shoes to the drum with the
brake gauge (Refer to 5 - BRAKES/HYDRAULIC/
MECHANICAL/BRAKE PADS/SHOES - ADJUST-
MENTS).
(9) Install the brake drum.
(10) Install the wheel and tire assembly (Refer to
22 - TIRES/WHEELS/WHEELS - STANDARD PRO-
CEDURE).
(11) Bleed the brake system,(Refer to 5 - BRAKES
- STANDARD PROCEDURE).
WHEEL CYLINDERS
REMOVAL
(1) Remove wheel and tire assembly.
(2) Remove brake drum.
(3) Install brake pedal prop rod.
(4) Disconnect wheel cylinder brake line.
(5) Remove brake shoe return springs and move
shoes out of engagement with cylinder push rods.
(6) Remove cylinder attaching bolts and remove
cylinder from support plate (Fig. 44).
DISASSEMBLY
(1) Remove push rods and boots (Fig. 45).
(2) Press pistons, cups and spring and expander
out of cylinder bore.
(3) Remove bleed screw.
CLEANING
Clean the cylinder and pistons with clean brake
fluid or brake cleaner only. Do not use any other
cleaning agents.
Dry the cylinder and pistons with compressed air.
Do not use rags or shop towels to dry the cylinder
components. Lint from cloth material will adhere to
the cylinder bores and pistons.
Fig. 43 SUPPORT PLATE 8 1/4
1 - SUPPORT PLATE
2 - MOUNTING NUTS
5 - 28 BRAKES - BASEKJ
SUPPORT PLATE (Continued)

in parallel with the IC where the two pigtail wire
leads connect to the IC pins.
The seat belt switch cannot be adjusted or repaired
and, if faulty or damaged, the entire seat belt buckle-
half unit must be replaced.
OPERATION
The seat belt switches are designed to provide a
status signal to the seat belt switch sense inputs of
the Airbag Control Module (ACM) indicating whether
the front seat belts are fastened. The ACM uses the
seat belt switch inputs as a factor in determining
what level of force with which it should deploy the
multistage driver and passenger airbags. In addition,
the ACM sends electronic messages to the ElectroMe-
chanical Instrument Cluster (EMIC) to control the
seat belt indicator based upon the status of the
driver side front seat belt switch. A spring-loaded
plastic slide with a small, enclosed permanent mag-
net is integral to the buckle latch mechanism. When
a seat belt tip-half is inserted and latched into the
seat belt buckle, the slide is pushed downward and
into close proximity of the Hall Effect Integrated Cir-
cuit (IC) chip within the buckle, which induces a cur-
rent within the chip. The chip provides this induced
current as an output to the ACM, which monitors the
current to determine the status of the front seat
belts. When the seat belt is unbuckled, the spring-
loaded slide and permanent magnet move upward
and away from the IC, causing the output current
from the seat belt switch to be reduced.
The seat belt switch receives a supply current from
the ACM, and the ACM senses the status of the front
seat belts through its pigtail wire connection to the
seat wire harness. The ACM also monitors the condi-
tion of the seat belt switch circuits through circuit
resistance created by the diagnostic resistor. The
ACM will illuminate the airbag indicator in the
EMIC and store a Diagnostic Trouble Code (DTC) for
any fault that is detected in either seat belt switch
circuit. For proper diagnosis of the seat belt switches,
a DRBIIItscan tool is required. Refer to the appro-
priate diagnostic information.
SEAT BELT TENSIONER
DESCRIPTION
A driver side seat belt tensioner supplements the
driver airbag system for all versions of this model
(Fig. 34). The seat belt tensioner is integral to the
driver side front seat belt and retractor unit, which is
secured to the B-pillar on the left side of the vehicle.
The retractor is concealed beneath the molded plastic
B-pillar trim. The seat belt tensioner consists prima-
rily of a molded plastic tensioner housing, a tubularmetal piston housing, a piston, a short rack gear, a
set of pinion gears, a pyrotechnically activated gas
generator, and a short pigtail wire. All of these com-
ponents are located on one side of the retractor spool
on the outside of the retractor housing. The seat belt
tensioner is controlled by the Airbag Control Module
(ACM) and is connected to the vehicle electrical sys-
tem through a dedicated take out of the body wire
harness by a keyed and latching molded plastic con-
nector insulator to ensure a secure connection.
The seat belt tensioner cannot be repaired and, if
faulty or damaged, the entire driver side front seat
belt and retractor unit must be replaced. The seat
belt tensioner is not intended for reuse and must be
replaced following a deployment. A locked retractor
that will not allow the seat belt webbing to be
retracted or extracted is a sure indication that the
seat belt tensioner has been deployed and requires
replacement. (Refer to 8 - ELECTRICAL/RE-
STRAINTS/FRONT SEAT BELT & RETRACTOR -
REMOVAL).
OPERATION
The seat belt tensioner is deployed by a signal gen-
erated by the Airbag Control Module (ACM) through
the driver seat belt tensioner line 1 and line 2 (or
squib) circuits. When the ACM sends the proper elec-
trical signal to the tensioner, the electrical energy
generates enough heat to initiate a small pyrotechnic
gas generator. The gas generator is installed in one
end of the tubular metal piston housing, which con-
tains a piston and a small rack gear. As the gas
expands, it pushes the piston and the rack gear
Fig. 34 Seat Belt Tensioner
1 - RETRACTOR
2 - TENSIONER HOUSING
3 - PISTON HOUSING
4 - PIGTAIL WIRE
5 - GAS GENERATOR
8O - 36 RESTRAINTSKJ
SEAT BELT SWITCH (Continued)