1994 JEEP CHEROKEE ECU

(12) Raise the vehicle.
(13) Install cable-to-frame retaining clip.
(14) Insert cable in equalizer and install equalizer
washer and nuts.
(15) Adjust parking brakes as described in Service
Adjustment section.
PARKING BRAKE REAR CABLE REPLACEMENT (YJ)
(1) Raise vehicle and loosen equalizer nuts (Fig.
15).
(2) Remove clamp and cotter pin attaching rear ca-
ble to equalizer and remove cable.
(3) Remove cable clips.
(4) Remove rear wheel and brake drum.
(5) Remove secondary brakeshoe and disconnect
cable from lever on brakeshoe.
(6) Compress cable retainer with hose clamp (Fig.
14) and remove cable from backing plate.
(7) Install new cable in backing plate. Be sure ca-
ble retainer lock tabs are engaged in plate.
(8) Install secondary brakeshoe.
(9) Adjust brakeshoes to brake drum and install
drum and wheel.
(10) Install cable in equalizer. Secure cable with
retainer and cotter pin.
(11) Install cable clips.
(12) Adjust parking brakes. Refer to procedure in
this section.
PARKING BRAKE ADJUSTMENT (XJ/YJ)
Parking brake adjustment is only necessary
when the tensioner, or a cable has been re-
placed or disconnected for service. When adjust-
ment is necessary, perform adjustment only as
described in the following procedure. This is
necessary to avoid faulty parking brake opera-
tion.
(1) Raise vehicle.
(2) Back off tensioner adjusting nut to create slack
in cables.
(3) Remove rear wheel/tire assemblies and remove
brake drums.
(4) Check rear brakeshoe adjustment with stan-
dard brake gauge. Also check condition of brake
parts as follows:
(a) Replace worn parts if necessary.Excessive
shoe-to-drum clearance, or worn brake compo-
nents will result in faulty parking brake ad-
justment and operation.
(b) Verify that parking brake cables operate
freely and are not binding, or seized. Replace faulty
cables, before proceeding.
(c) Adjust rear brakeshoes shoes to drum.
(5) Reinstall brake drums and wheel/tire assem-
blies after brakeshoe adjustment is complete.
Fig. 15 Parking Brake Cables (YJ)
JPARKING BRAKES 5 - 63

(4) Remove retainer clip securing booster push rod
to pedal (Fig. 3).
(5) Remove nut securing pedal shaft in support
bracket.
(6) Slide pedal shaft outward for clearance and re-
move brake pedal.
(7) Remove pedal bushings if they are to be re-
placed.
BRAKE PEDAL INSTALLATION
(1) Install new bushings in pedal. Lubricate bush-
ings and pivot pin with Mopar multi mileage grease.
(2) Position pedal, sleeve and spacer(s) in bracket
and install pivot pin.
(3) Install new nut on pivot pin.Pivot pin nut is
specially formed and should not be reused. Be
sure to install new nut to secure pin.
(4) ) Tighten new pivot pin nut to 27 Nzm (20 ft.
lbs.) on models with manual transmission. Tighten
nut to 35 Nzm (26 ft. lbs.) on models with automatic
transmission.
(5) Install booster push rod on pedal pin (Fig. 3).
Secure push rod with original, or new retainer clip if
necessary.
(6) Install dash brace rod, if equipped.
(7) Check and adjust brakelight switch if neces-
sary. Refer to procedure in this section.
BRAKELIGHT SWITCH REMOVAL
The brakelight switch is mounted in the pedal sup-
port bracket and is operated by the pedal. The switch
is secured in the bracket with a retainer (Fig. 4).
(1) Remove steering column cover and lower trim
panel for switch access, if necessary.
(2) Disconnect switch wires.
(3) Thread switch out of retainer, or rock switch
up/down and pull it rearward out of retainer.
(4) Inspect switch retainer. Replace retainer if
worn, distorted, loose, or damaged.
BRAKELIGHT SWITCH INSTALLATION
(1) Insert replacement switch in retainer. Thread
switch into place or rock it up/down until switch
plunger touches brake pedal.
(2) Connect switch wires.
(3) Check switch operation. Adjust switch position
if necessary. Refer to procedures in this section.
(4) Install trim panels (if removed).
BRAKELIGHT SWITCH ADJUSTMENT
A plunger-type brakelight switch is used on XJ
and YJ models (Fig. 4). The switch plunger is actu-
ated directly by the brake pedal.
The switch internal contacts are open when the
brake pedal is in the released position. Brake appli-
cation moves the pedal away from the switch allow-
ing the plunger to extend. As the plunger extends,
the switch internal contacts close completing the cir-
cuit to the brakelights.
A circular, metal clip is used to secure the switch
to the bracket on the pedal support. The clip has
tangs that seat in the threads of the switch plunger
barrel.
SWITCH ADJUSTMENT PROCEDURE
(1) Check switch adjustment. Move the brake
pedal forward by hand and note operation of the
switch plunger. Plunger should be fully extended
when pedal free play is taken up and brake applica-
tion begins. A clearance of approximately 3 mm (1/8
in.) should exist between plunger and pedal at this
point.
(a) If switch-to-pedal clearance is OK and brake-
lights operate correctly, adjustment is not required.
(b) If switch plunger does not fully extend and
clearance between pedal and switch barrel is insuf-
ficient, adjust switch position as described in step
(2).
Fig. 3 Push Rod Attachment At Brake Pedal (XJ)
Fig. 4 Brakelight Switch Mounting And Location
(XJ/YJ)
5 - 66 BRAKE PEDAL AND BRAKELIGHT SWITCHJ

CLUTCH DIAGNOSIS
INDEX
page page
Clutch Problem Causes..................... 3
General Diagnosis Information................ 3Inspection and Diagnosis Charts.............. 4
GENERAL DIAGNOSIS INFORMATION
Unless the cause of a clutch problem is obvious, ac-
curate problem diagnosis will usually require a road
test to confirm a problem. Component inspection will
then be required to determine the actual problem
cause.
During a road test, drive the vehicle at normal
speeds. Shift the transmission through all gear
ranges and observe clutch action. If chatter, grab,
slip, or improper release is experienced, remove and
inspect the clutch components. However, if the prob-
lem is noise or hard shifting, further diagnosis may
be needed as the transmission or another driveline
component may be at fault. Careful observation dur-
ing the test will help narrow the problem area.
CLUTCH PROBLEM CAUSES
CONTAMINATION
Fluid contamination is a frequent cause of clutch
malfunctions. Oil, water, or clutch fluid on the clutch
contact surfaces will cause faulty operation. The
usual result is chatter, slip and grab.
During inspection, note if any components are con-
taminated with oil, hydraulic fluid, or water/road
splash.
Oil contamination indicates a leak at either the
rear main seal or transmission input shaft. Oil leak-
age produces a residue of oil on the housing interior
and on the clutch cover and flywheel. Heat buildup
caused by slippage between the cover, disc and fly-
wheel, can sometimes bake the oil residue onto the
components. The glaze-like residue ranges in color
from amber to black.
Road splash contamination means dirt/water is en-
tering the clutch housing due to loose bolts, housing
cracks, or through hydraulic line openings. Driving
through deep water puddles can force water/road
splash into the housing through such openings.
Clutch fluid leaks are from loose or damaged slave
cylinder fluid lines and connecting fittings. However,
clutch fluid leaks will usually be noted and corrected
before severe contamination occurs.
CLUTCH MISALIGNMENT
Clutch components must be in proper alignment
with the crankshaft and transmission input shaft.Misalignment caused by excessive runout or warpage
of any clutch component will cause grab, chatter and
improper clutch release.
Flywheel Runout
Check flywheel runout whenever misalignment is
suspected. Flywheel runout should not exceed 0.08
mm (0.003 in.). Measure runout at the outer edge of
the flywheel face with a dial indicator. Mount the in-
dicator on a stud installed in place of one of the fly-
wheel bolts.
Common causes of runout are:
²heat warpage
²improper machining
²incorrect bolt tightening
²improper seating on crankshaft flange shoulder
²foreign material on crankshaft flange
Flywheel machining is not recommended. The fly-
wheel clutch surface is machined to a unique contour
and machining will negate this feature. However,
minor flywheel scoring can be cleaned up by hand
with 180 grit emery, or with surface grinding equip-
ment. Remove only enough material to reduce scor-
ing (approximately 0.001 - 0.003 in.). Heavy stock
removal isnot recommended.Replace the flywheel
if scoring is severe and deeper than 0.076 mm (0.003
in.). Excessive stock removal can result in flywheel
cracking or warpage after installation; it can also
weaken the flywheel and interfere with proper clutch
release.
Clean the crankshaft flange before mounting the
flywheel. Dirt and grease on the flange surface may
cock the flywheel causing excessive runout. Use new
bolts when remounting a flywheel and secure the
bolts with Mopar Lock And Seal. Tighten flywheel
bolts to specified torque only. Overtightening can dis-
tort the flywheel hub causing runout.
Clutch Cover And Disc Runout
Check the clutch disc before installation. Axial
(face) runout of anewdisc should not exceed 0.50
mm (0.020 in.). Measure runout about 6 mm (1/4 in.)
from the outer edge of the disc facing. Obtain an-
other disc if runout is excessive.
Check condition of the clutch before installation. A
warped cover or diaphragm spring will cause grab
and incomplete release or engagement. Be careful
JCLUTCH DIAGNOSIS 6 - 3

RELEASE BEARING REPLACEMENT
(1) Remove transmission as described in Group 21.
(2) Disconnect release bearing from release lever
and remove bearing (Fig. 5).
(3) Inspect bearing slide surface of transmission
front bearing retainer. Replace retainer if slide sur-
face is scored, worn, or cracked.
(4) Inspect release fork and fork pivot. Be sure
pivot is secure and in good condition. Be sure fork is
not distorted or worn. Replace release fork retainer
spring if bent or damaged in any way.
(5) Lubricate crankshaft pilot bearing with Mopar
high temperature bearing grease. Apply grease to
end of long shank, small diameter flat blade screw-
driver. Then insert tool through clutch disc hub to
reach bearing.
(6) Lubricate input shaft splines, bearing retainer
slide surface, fork pivot and release fork pivot sur-face with Mopar high temperature grease.
(7) Install new release bearing. Be sure bearing is
properly secured to release fork.
(8) Install transmission as described in Group 21.
PILOT BEARING REPLACEMENT
(1) Remove transmission. Refer to Group 21 for
procedure.
(2) Remove clutch cover and disc.
(3) Remove pilot bearing. Use internal (blind hole)
puller such those as supplied in Snap On Tool Set
CG40CB to remove bearing.
(4) Lubricate new bearing with Mopar high tem-
perature bearing grease.
(5) Start new bearing into crankshaft by hand.
Then seat bearing with clutch alignment tool (Fig.
6).
(6) Lightly scuff sand flywheel surface with 180
grit emery cloth. Then clean surface with wax and
grease remover.
(7) Install clutch disc and cover as described in
this section.
(8) Install transmission. Refer to Group 21 for pro-
cedure.
CLUTCH HOUSING REPLACEMENT
The AX 15 clutch housing is removable and can be
replaced when the transmission is out of the vehicle.
The bolts attaching the housing to the transmis-
sion case are located inside the housing (Fig. 7). Rec-
ommended tightening torque for the clutch housing-
to-transmission bolts is 38 Nzm (28 ft. lbs.).
Be sure the transmission and housing mating
surfaces are clean before installing an original,
or replacement clutch housing. Dirt/foreign ma-
terial trapped between the housing and trans-
mission will cause misalignment. If
misalignment is severe enough, the result will be
clutch drag, incomplete release and hard shift-
ing.
CLUTCH HYDRAULIC LINKAGE REMOVAL
The clutch master cylinder, slave cylinder and
connecting line are serviced as an assembly
only. The linkage components cannot be over-
hauled or serviced separately. The cylinders and
connecting line are sealed units. Also note that
removal/installation procedures for right and
left hand drive models are basically the same.
Only master cylinder location is different.
(1) Raise vehicle.
(2) Remove fasteners attaching slave cylinder to
clutch housing.
(3) Remove slave cylinder from clutch housing
(Fig. 8).
(4) Disengage clutch fluid line from body clips.
(5) Lower vehicle.
Fig. 2 Clutch Disc Position
Fig. 3 Typical Method Of Aligning Clutch Disc
JCLUTCH SERVICE 6 - 11

(6) Verify that cap on clutch master cylinder reser-
voir is tight. This is necessary to avoid undue spill-
age during removal.
(7) Remove clutch master cylinder attaching nuts.
Note that one nut is accessible from engine compart-
ment and one nut is accessible from under instru-
ment panel (Figs. 9 and 10).
(8) Remove clip securing clutch master cylinder
push rod to pedal and slide push rod off pedal pin.
(9) If pedal pin is equipped with bushing, inspect
condition of bushing and replace it if worn or dam-
aged.
(10) Remove clutch hydraulic linkage through en-
gine compartment.
CLUTCH HYDRAULIC LINKAGE INSTALLATION
(1) Be sure reservoir cover on clutch master cylin-
der is tight to avoid spills.
Fig. 4 Manual Transmission Mounting
Fig. 5 Release Bearing Attachment
Fig. 6 Pilot Bearing Installation
6 - 12 CLUTCH SERVICEJ

(4) Attach clutch master cylinder push rod to pin
on clutch pedal. Secure rod with new clip if neces-
sary.
(5) Install and tighten clutch master cylinder at-
taching nuts to 23-34 Nzm (200-300 in. lbs.) torque.
(6) Raise vehicle.
(7) Insert slave cylinder push rod through clutch
housing opening and into release lever. Be sure cap
on end of rod is securely engaged in lever. Check this
before installing cylinder attaching nuts.
(8) Install and tighten slave cylinder attaching
nuts to 23-34 Nzm (200-300 in. lbs.) torque.
(9) Secure clutch fluid line in body clips and lower
vehicle.
CLUTCH FLUID LEVEL
The clutch fluid reservoir, master cylinder, slave
cylinder and fluid lines are prefilled with fluid at the
factory during assembly operations.
The hydraulic system should not require additional
fluid under normal circumstances. In fact,the reser-
voir fluid level will actually increase as normal
clutch wear occurs. For this reason, it is impor-
tant to avoid overfilling, or removing fluid from
the reservoir.
If inspection or diagnosis indicates additional fluid
may be needed, use Mopar brake fluid, or an equiv-
alent meeting standards SAE J1703 and DOT 3. Do
not use any other type of fluid.
Clutch fluid level is checked at the master cylinder
reservoir (Fig. 12). An indicator ring is provided ei-
ther on the side, or interior rim of the reservoir (Fig.
13).
Be sure to wipe the reservoir and cover clean be-
fore removing the cover. This will avoid having dirt
or foreign material fall into the reservoir during a
fluid level check.
Fig. 10 Clutch Master Cylinder Location (Right Hand
Drive Models)
Fig. 11 Clutch Master Cylinder Mounting (Typical)
Fig. 12 Clutch Master Cylinder Reservoir And Cap
Fig. 13 Reservoir Fluid Level Indicator Ring
6 - 14 CLUTCH SERVICEJ

CLUTCH PEDAL REMOVAL
(1) Remove instrument panel lower trim cover for
extra working clearance.
(2) Remove retainer clip and washers that attach
clutch master cylinder push rod to pedal.
(3) On YJ, remove retaining ring securing pedal to
pivot shaft (Fig. 14). On XJ, remove nut securing
pedal to pivot shaft (Fig. 15).
(4) Move pedal pivot shaft to right and slide pedal
off shaft.
CLUTCH PEDAL INSTALLATION
(1) Lubricate clutch pedal pivot shaft and pedal
bushings or sleeve with Mopar multi-mileage grease.
(2) Position pedal on pivot shaft and through
brace. Secure pedal with washer and retaining ring
on YJ, or with washer and nut on XJ.
(3) Install clutch master cylinder push rod on
pedal. Secure rod with washer(s) and new cotter pin.
(4) Install instrument panel lower trim cover, if re-
moved.
FLYWHEEL SERVICE
Inspect the flywheel whenever the clutch disc,
cover and housing are removed for service. Check
condition of the flywheel face, hub, ring gear teeth,
and flywheel bolts.
Minor scratches, burrs, or glazing on the flywheel
face can be reduced with 180 grit emery cloth. How-
ever, the flywheel should be replaced if the disc con-
tact surface is severely scored, heat checked, cracked,
or obviously worn.
Flywheel machining is not recommended. The fly-
wheel surface is manufactured with a unique contourthat would be negated by machining. However,
cleanup of minor flywheel scoring can be performed
by hand with 180 grit emery, or with surface grind-
ing equipment. Replace the flywheel if scoring is
deeper than 0.0762 mm (0.003 in.).
Heavy stock removal by grinding isnot recom-
mended.Excessive stock removal can result in fly-
wheel cracking or warpage after installation. It can
also weaken the flywheel and interfere with proper
clutch release.
Fig. 14 Clutch Pedal Mounting (YJ)
Fig. 15 Clutch Pedal Mounting (XJ)
JCLUTCH SERVICE 6 - 15

speed of the fan to a predetermined maximum level
at higher engine speeds. A bimetallic spring coil is
located on the front face. This spring coil reacts to
the temperature of the radiator discharge air. It en-
gages the viscous fan drive for higher fan speed if
the air temperature from the radiator rises above a
certain point. Until additional engine cooling is nec-
essary, the fan will remain at a reduced rpm regard-
less of engine speed.
Only when sufficient heat is present, will the vis-
cous fan drive engage. This is when the air flowing
through the radiator core causes a reaction from the
bimetallic coil. It then increases fan speed to provide
the necessary additional engine cooling.
Once the engine has cooled, the radiator discharge
temperature will drop. The bimetallic coil again re-
acts and the fan speed is reduced to the previous dis-
engaged speed.
CAUTION: Engines equipped with serpentine drive
belts have reverse rotating fans and viscous fan
drives. They are marked with the word REVERSE to
designate their usage. Installation of the wrong fan
or viscous fan drive can result in engine overheat-
ing.
VISCOUS FAN DRIVE TEST
The cooling system must be in good condition. This
is checked prior to performing the following test. It
also will ensure against excessively high coolant
temperature.
CAUTION: Be sure that there is adequate fan blade
clearance before drilling.(1) Drill a 3.18-mm (1/8-in) diameter hole in the
top center of the fan shroud.
(2) Obtain a dial thermometer with an 8 inch stem
(or equivalent). It should have a range of -18É-to-
105ÉC (0É-to-220É F). Insert thermometer through the
hole in the shroud. Be sure that there is adequate
clearance from the fan blades.
(3) Connect a tachometer and an engine ignition
timing light (timing light is to be used as a strobe
light).
(4) Block the air flow through the radiator. Secure
a sheet of plastic in front of the radiator (or air con-
ditioner condenser). Use tape at the top to secure the
plastic and be sure that the air flow is blocked.
(5) Be sure that the air conditioner (if equipped) is
turned off.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A DI-
RECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR FAN. DO
NOT WEAR LOOSE CLOTHING.
(6) Start the engine and operate at 2400 rpm with
the timing light (strobe light) aimed at the fan
blades. Within ten minutes the air temperature (in-
dicated on the dial thermometer) should be 88É C
(190É F). Satisfactory operation of the fan drive re-
quires that it engage before or at 88É C (190É F). En-
gagement is distinguishable by a definite increase in
flow noise. The timing light also will indicate an in-
crease in the speed of the fan.
(7) When the air temperature reaches 88É C (190É
F), remove the plastic sheet. Satisfactory operation of
the viscous fan requires the air temperature to drop
20É F (11É C) or more. A definite decrease of audible-
fan-air-flow-noise should be noticed. Replace defec-
tive fan assemblies.
VISCOUS FAN DRIVE REPLACEMENT
REMOVAL
Some engines have the mechanical fan/viscous fan
drive assembly mounted directly to the water pump
hub (Fig. 38). It may also be mounted to a hub/bear-
ing attached to an aluminum bracket on the right
front side of engine (Fig. 39).
(1) Loosen but do not remove at this time, the four
fan hub mounting nuts (Figs. 38 or 39).
(2) Remove accessory serpentine drive belt. Refer
to Belt Service in the Engine Accessory Drive Belt
section of this group.
(3) Some models with certain engines may require
the removal of the fan shroud to remove the viscous
fan drive. The fan shroud and fan blade/viscous fan
drive should be removed from the vehicle as one as-
sembly.
Fig. 37 Viscous Fan DriveÐTypical
JCOOLING SYSTEM 7 - 27