1995 JEEP XJ brake rotor

CALIPER INSTALLATION
(1) Install brakeshoes in caliper (Figs. 11, 12).
(2) Connect brake hose to caliper but do not
tighten fitting bolt completely at this time.Be sure
to use new gaskets on fitting bolt to avoid leaks
(Fig. 25).
(3) Install caliper. Position mounting notches at
lower end of brakeshoes on bottom mounting ledge
(Fig. 13). Then rotate caliper over rotor and seat
notches at upper end of shoes on mounting ledge
(Fig. 13).
(4) Coat caliper mounting bolts with GE 661 or
Dow 111 silicone grease. Then install and tighten
bolts to 10-20 Nzm (7-15 ft. lbs.) torque.CAUTION: If new caliper bolts are being installed,
or if the original reason for repair was a drag/pull
condition, check caliper bolt length before proceed-
ing. If the bolts have a shank length greater than
67.6 mm (2.66 in.), they may contact the inboard
brakeshoe causing a partial apply condition. Refer
to Figure 14 for the required caliper bolt length.
(5) Position front brake hose clear of all chassis
components and tighten caliper fitting bolt to 31 Nzm
(23 ft. lbs.) torque.
CAUTION: Be sure the brake hose is not twisted or
kinked at any point. Also be sure the hose is clear
of all steering and suspension components. Loosen
and reposition the hose if necessary.
(6) Install wheels. Tighten wheel lug nuts to 109-
150 Nzm (80-110 ft. lbs.) torque.
(7) Fill and bleed brake system. Refer to proce-
dures in Service Adjustments section.
ROTOR REMOVAL
(1) Raise vehicle and remove wheel.
(2) Remove caliper.
(3) Remove retainers securing rotor to hub studs
(Fig. 26).
(4) Remove rotor from hub (Fig. 26).
(5) If rotor shield requires service, remove front
hub and bearing assembly.
ROTOR INSTALLATION
(1) If new rotor is being installed, remove protec-
tive coating from rotor surfaces with Mopar carb
cleaner.It is not necessary to machine a rotor to
remove the coating. Mopar carb cleaner fol-
lowed by a rinse with brake cleaner will re-
move the coating.
(2) Install rotor on hub.
(3) Install caliper.
Fig. 23 Installing Caliper Piston
Fig. 24 Seating Caliper Piston Dust Boot
Fig. 25 Front Brake Hose And Fitting Components
JDISC BRAKES 5 - 51

(4) Install new spring nuts on wheel studs.
(5) Install wheel and lower vehicle.
DISC BRAKE ROTOR THICKNESS
Rotor minimum usable thickness is 22.7 mm (0.89
in.). This dimension is either cast, or stamped on the
rotor hub, or outer edge.
Measure rotor thickness at the center of the brake-
shoe contact surface.
Replace the rotor if worn below minimum thick-
ness. Also replace the rotor if refinishing would re-
duce thickness below the allowable minimum.
DISC BRAKE ROTOR RUNOUT
Check rotor lateral runout whenever pedal pulsa-
tion, or rapid, uneven brakelining wear has occurred.
On 4-wheel drive models, the rotor must be se-
curely 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 as shown (Fig. 27).
Use a dial indicator to check lateral runout (Fig.
27).
Maximum allowable rotor lateral runout is 0.13
mm (0.005 in.).
Check lateral runout with a dial indicator (Fig. 28).
Excessive lateral runout will cause brake pedal pul-
sation and rapid, uneven wear of the brakeshoes.
Maximum allowable rotor runout for all models is
0.12 mm (0.005 in.).
DISC BRAKE ROTOR THICKNESS VARIATION
Variations in rotor thickness will cause pedal pul-
sation, noise and shudder.
Measure rotor thickness at four to six points
around the rotor face. Position the micrometer ap-
proximately 2 cm (3/4 in.) from the rotor outer cir-
cumference for each measurement (Fig. 29).
Thickness should notvaryby more than 0.013 mm
(0.0005 in.) from point-to-point on the rotor. Refinish
or replace the rotor if necessary.
Fig. 26 Rotor And HubFig. 27 Securing4x4Rotor For Lateral Runout Check
Fig. 28 Typical Method Of Checking Rotor Lateral
Runout
Fig. 29 Measuring Rotor Thickness Variation
5 - 52 DISC BRAKESJ

DISC BRAKE ROTOR REFINISHING
When To Refinish
Rotor braking surfaces can be refinished by sand-
ing and/or machining in a disc brake lathe. However,
the rotor should be cleaned and inspected before-
hand. Careful inspection will avoid refinishing rotors
with very little service life left in them.
Pay particular attention to rotors that are heavily
rusted, or corroded. Accumulated rust/corrosion on
braking surfaces and ventilating ribs may extend to
a depth beyond acceptable limits. This can be espe-
cially true on: (a) high mileage vehicles; (b) vehicles
regularly exposed to road salt during winter months;
(c) vehicles operated in coastal regions where salt air/
road splash is a factor; (d) and vehicles used for ex-
tensive off-road operation.
New rotors have a protective coating that should be
removed before installation.It is not necessary to
machine a rotor to remove this coating. The
coating is easily removed with Mopar carb
cleaner followed by a rinse with Mopar brake
cleaner. A scotch brite pad, or steel wool can
also be used to help loosen and remove the
coating if desired.
Recommended Refinishing Equipment
The brake lathe must be capable of machining both
rotor surfaces simultaneously with dual cutter heads
(Fig. 30).Equipment capable of machining only
one side at a time will produce a tapered rotor.
The lathe should also be equipped with a grinder at-
tachment, or dual sanding discs for final cleanup or
light refinishing.
Refinishing Techniques
If the rotor surfaces only need minor cleanup of
rust, scale, or scoring, use abrasive sanding discs to
clean up the rotor surfaces. However, when a rotor is
scored or worn, machining with cutting tools will be
required.
Light cuts are recommended when machining the
rotor surfaces. Heavy feed rates are not recom-
mended and may result in chatter marks, or taper.
CAUTION: Never refinish a rotor if machining would
cause the rotor to fall below minimum allowable
thickness.
The final finish on the rotor should be a non-direc-
tional, cross hatch pattern (Fig. 31). Use sanding
discs to produce this finish.
Fig. 30 Rotor Refinishing Equipment
JDISC BRAKES 5 - 53

WHEEL NUT TIGHTENING
The wheel attaching nuts must be tightened prop-
erly to ensure efficient brake operation. Overtighten-
ing the nuts or tightening them in the wrong
sequence can cause distortion of the brake rotors and
drums. Impact wrenches are not really recommended
for tightening wheel nuts. A torque wrench should be
used for this purpose.
A light coat of LPS Anti-Corrosion spray lube
around the hub face and on the studs will cut down
on rust/corrosion formation.The correct tightening sequence is important in
avoiding rotor and drum distortion. The correct se-
quence is in a diagonal crossing pattern (Fig. 32).
Recommended torque range for XJ/YJ wheel nuts
is 108-149 Nzm (80-110 ft. lbs.). Preferred set-to
torque is 129 Nzm (95 ft. lbs.) torque.
Seat the wheel and install the wheel nuts finger
tight. Tighten the nuts in the sequence to 1/2 the re-
quired torque. Then repeat the tightening sequence
to final specified torque.
Fig. 31 Preferred Rotor Surface Finish
Fig. 32 Wheel Nut Tightening Sequence
5 - 54 DISC BRAKESJ

If the brake drums are heavily coated with rust,
clean and inspect them carefully. Rust damage on
high mileage drums can be severe enough to require
replacement.
New drums have a protective coating that should
be removed before installation.It is not necessary
to machine a drum to remove this coating. The
coating is easily removed with Mopar carb
cleaner followed by a rinse with Mopar brake
cleaner. A scotch brite pad, or steel wool can
also be used to help loosen and remove the
coating if desired.
The maximum allowable diameter for the drum
braking surface is usually indicated on the drum
outer face (Fig. 11).
WHEEL NUT TIGHTENING
The wheel attaching lug nuts must be tightened
properly to ensure efficient brake operation. Over-tightening the nuts or tightening them in the wrong
sequence can cause distortion of the brake rotors and
drums.
Impact wrenches are not recommended for tighten-
ing wheel nuts. A torque wrench should be used for
this purpose.
A light coat of LPS Anti-Corrosion spray lube
around the hub face and on the studs will cut down
on rust/corrosion formation.
The correct tightening sequence is important in
avoiding rotor and drum distortion. The correct se-
quence is in a diagonal crossing pattern (Fig. 12).
Recommended torque range for XJ/YJ wheel nuts
is 109-150 Nzm (80-110 ft. lbs.).
Seat the wheel and install the wheel nuts finger
tight. Tighten the nuts in the sequence to half the re-
quired torque. Then repeat the tightening sequence
to final specified torque.
Fig. 11 Typical Location Of Brake Drum Refinish
Limit
Fig. 12 Wheel Nut Tightening Sequence
JDRUM BRAKES 5 - 59

IGNITION SECONDARY CIRCUIT DIAGNOSIS
CHECKING FOR SPARK
CAUTION: When disconnecting a high voltage cable
from a spark plug or from the distributor cap, twist
the rubber boot slightly (1/2 turn) to break it loose
(Fig. 12). Grasp the boot (not the cable) and pull it
off with a steady, even force.
(1) Disconnect the ignition coil secondary cable
from center tower of the distributor cap. Hold the ca-
ble terminal approximately 12 mm (1/2 in.) from a
good engine ground (Fig. 13).
WARNING: BE VERY CAREFUL WHEN THE ENGINE
IS CRANKING. DO NOT PUT YOUR HANDS NEAR
THE PULLEYS, BELTS OR THE FAN. DO NOT WEAR
LOOSE FITTING CLOTHING.
(2) Rotate (crank) the engine with the starter mo-
tor and observe the cable terminal for a steady arc. If
steady arcing does not occur, inspect the secondary
coil cable. Refer to Spark Plug Cables in this group.
Also inspect the distributor cap and rotor for cracksor burn marks. Repair as necessary. If steady arcing
occurs, connect ignition coil cable to the distributor
cap.
(3) Remove a cable from one spark plug.
(4) Using insulated pliers, hold the cable terminal
approximately 12 mm (1/2 in.) from the engine cylin-
der head or block while rotating the engine with the
starter motor. Observe the spark plug cable terminal
for an arc. If steady arcing occurs, it can be expected
that the ignition secondary system is operating cor-
rectly.(note that if the ignition coil cable is re-
moved for this test, instead of a spark plug
cable, the spark intensity will be much higher.)
If steady arcing occurs at the spark plug cables, but
the engine will not start, connect the DRB scan tool.
Refer to the Powertrain Diagnostic Procedures ser-
vice manual.
FAILURE TO START TEST
To prevent unnecessary diagnostic time and wrong
test results, the previous Checking For Spark test
should be performed prior to this test.
WARNING: SET PARKING BRAKE OR BLOCK THE
DRIVE WHEELS BEFORE PROCEEDING WITH THIS
TEST.
(1) Unplug the ignition coil harness connector at
the coil (Fig. 14).
(2) Connect a set of small jumper wires (18 gauge
or smaller) between the disconnected harness termi-
nals and the ignition coil terminals. To determine po-
larity at connector and coil, refer to the Wiring
Diagrams section.
(3) Attach one lead of a voltmeter to the positive
(12 volt) jumper wire. Attach the negative side of
voltmeter to a good ground. Determine that sufficient
battery voltage (12.4 volts) is present for the starting
and ignition systems.
Fig. 12 Cable Removal
Fig. 13 Checking for SparkÐTypical
Fig. 14 Coil Harness ConnectorÐTypical (4.0L
Shown)
8D - 10 IGNITION SYSTEMSJ

The transmission speed sensor consists of a rotor
and magnet on the transmission output shaft and a
switch in the extension housing or adapter. The sen-
sor switch is activated each time the rotor and mag-
net complete one revolution. Sensor signals are sent
to the transmission control module.
The park/neutral position switch is mounted on the
valve body manual shaft. The switch signals shift
linkage and manual valve position to the transmis-
sion control module through an interconnecting har-
ness. The switch prevents engine starting in all gears
other than Park or Neutral.
The brake switch is in circuit with the torque con-
verter clutch solenoid. The switch disengages the
converter clutch whenever the brakes are applied.
The switch is mounted on the brake pedal bracket
and signals the transmission control module when
the pedal is pressed or released.
TORQUE CONVERTER
A three element torque converter is used for all ap-
plications. The converter contains an impeller, stator,
and turbine.
The AW-4 converters are all equipped with a con-
verter clutch mechanism. The clutch consists of a
sliding clutch piston, clutch springs and the clutch
disc material (Fig. 4). The clutch provides optimum
torque transfer and economy when engaged.
The clutch disc is attached to the converter front
cover. The clutch piston and clutch springs are at-
tached to the turbine hub. The springs dampen en-
gine firing impulses and loads during the initial
phase of converter clutch engagement.
Clutch engagement is controlled by transmission
valve body solenoid number three and by the con-
verter clutch relay valve. The solenoid channels line
pressure to the clutch through the relay valve at
clutch engagement speeds.Torque converter clutch engagement occurs in sec-
ond gear in 1-2 position; third gear in 3 position and
third and fourth gear in D position.
FOURTH GEAR OVERDRIVE COMPONENTS
The overdrive system consists of the input shaft,
one-way clutch, planetary sun gear, ring gear, plane-
tary carrier, clutch and overdrive brake (Fig. 5). The
overdrive elements are controlled and applied
through transmission valve body solenoid number
two.
In overdrive fourth gear, the brake prevents the
overdrive sun gear from turning. During operation,
the overdrive elements operate as follows:
Fig. 4 Torque Converter (With Clutch)
Fig. 5 Fourth Gear Overdrive Components
JAW-4 AUTOMATIC TRANSMISSION 21 - 167

AW-4 IN-VEHICLE SERVICE
INDEX
page page
Accumulator Pistons and Springs............. 189
Adapter Housing Seal Replacement........... 191
Checking Fluid Level and Condition........... 182
Manual Valve Shaft Seal Replacement......... 187
Park Interlock Cable Adjustment............. 195
Park Rod and Pawl Service................. 190
Park/Neutral Position Switch................ 183
Refilling After Overhaul or Fluid/Filter Change . . . 182
Second Coast Brake Servo................. 190
Shift Cable Adjustment.................... 195
Speed Sensor........................... 192Speed Sensor RotorÐSpeedometer Drive Gear . . 193
Throttle Position Sensor (TPS) Service........ 193
Transmission Control Module (TCM) Service.... 183
Transmission Cooler Line Fittings............ 197
Transmission Cooler Service................ 196
Transmission Throttle Cable Adjustment........ 194
Transmission Throttle Cable Replacement...... 193
Transmission Valve Body Installation.......... 187
Transmission Valve Body Removal........... 186
Transmission Valve Body Solenoids........... 184
CHECKING FLUID LEVEL AND CONDITION
Recommended fluid for AW-4 transmissions is Mo-
par Dexron IIE/Mercon.
Mopar Dexron II can also be used but only when
Mercon fluid is not available.
CHECKING FLUID LEVEL
(1) Be sure transmission fluid is at normal operat-
ing temperature. Normal operating temperature is
reached after approximately 15 miles (25 km) of op-
eration.
(2) Position vehicle on level surface. This is impor-
tant for an accurate fluid level check.
(3) Shift transmission through all gear ranges and
back to Park.
(4) Apply parking brakes.
(5) Verify that transmission is in Park.
(6) Wipe off dipstick handle to prevent dirt from
entering fill tube. Then remove dipstick and check
fluid level and condition.
(7) Correct fluid level isto FULL mark on dip-
stick when fluid is at normal operating temper-
ature(Fig. 1).
(8) If fluid level is low, top off level with Mopar
Dexron IIE/Mercon. Mopar Dexron II can be used but
only if Mercon is not available.Do not overfill
transmission. Add only enough fluid to bring
level to Full mark.
(9) If too much fluid was added, excess amount can
be removed with suction gun and appropriate diame-
ter plastic tubing. Tubing only has to be long enough
to extend into oil pan.
CHECKING FLUID CONDITION
Inspect the appearance of the fluid during the fluid
level check. Fluid color should range from dark red to
pink and be free of foreign material, or particles. If
the fluid is dark brown or black in color and smells
burnt, the fluid has been overheated and must be
changed.Transmission operation should also be checked if
the fluid is severely discolored and contains quanti-
ties of foreign material, metal particles, or clutch disc
friction material.
A small quantity of friction material or metal
particles in the oil pan is normal. The particles
are usually generated during the break-in pe-
riod and indicate normal seating of the various
transmission components.
REFILLING AFTER OVERHAUL OR FLUID/FILTER
CHANGE
The best way to refill the transmission after a fluid
change or overhaul is as follows:
(1) If transmission has been overhauled, install
transmission in vehicle.
(2) Remove dipstick and insert clean funnel in
transmission fill tube.
(3) Add following initial quantity of Mopar Dexron
IIE/Mercon to transmission:
(a) If fluid/filter change was performed, add4
pints (2 quarts)of fluid to transmission.
(b) If transmission was completely overhauled
and torque converter was replaced or drained, add
10 pints (5 quarts)of fluid to transmission.
(c) Remove funnel and install dipstick.
(4) Operate vehicle until fluid reaches normal op-
erating temperature.
(5) Apply parking brakes.
Fig. 1 Transmission Fluid Level
21 - 182 AW-4 IN-VEHICLE SERVICEJ