Tow JEEP CHEROKEE 1994 Service Owner's Manual

pressure is bleeding past the (in-tank mounted) fuel
pump outlet check valve. Replace Fuel Pump Module
assembly. Refer to Fuel Pump Module removal and
installation in this group. If pressure drop is within
specifications, proceed to next step.
(13) Clamp off the rubber hose portion of adapter
tool number 6631 connected to the fuel supply line.
Allow engine to set for 30 minutes. If pressure has
dropped more than 138 kPa (20 psi) in 30 minutes,
pressure is bleeding past the fuel pressure regulator.
Replace fuel pressure regulator. Refer to Fuel Rail
removal and installation in the Component Removal/
Installation section of this group.
MECHANICAL MALFUNCTIONS
Mechanical malfunctions are more difficult to diag-
nose with this system. The powertrain control mod-
ule (PCM) has been programmed to compensate for
some mechanical malfunctions such as incorrect cam
timing, vacuum leaks, etc. If engine performance
problems are encountered and diagnostic trouble
codes are not displayed, the problem may be mechan-
ical rather than electronic.
FUEL FILTER
The fuel filter protects the fuel injectors and fuel
pressure regulator from dirt, water and other foreign
matter. The filter is located under the vehicle along
the frame rail (Figs. 13 or 14). Replace fuel filter at
intervals specified in the Lubrication and Mainte-
nance Schedule chart found in Group 0, Lubrication
and Maintenance.
REMOVAL
WARNING: THE FUEL SYSTEM IS UNDER CON-
STANT FUEL PRESSURE (EVEN WITH THE ENGINE
OFF) OF APPROXIMATELY 131-269 KPA (19-39
PSI). THIS PRESSURE MUST BE RELEASED BE-
FORE SERVICING THE FUEL FILTER.
(1) Disconnect negative battery cable. Remove fuel
filler cap.
WARNING: FUEL PRESSURE MUST BE RELEASED
BEFORE DISCONNECTING ANY FUEL SYSTEM
COMPONENT.
(2) Release fuel system pressure. Refer to Fuel
Pressure Release Procedure in this group.
(3) Raise and support vehicle.
(4) On YJ models remove the fuel filter shield
(Fig. 13).
(5) Remove hoses and clamps from inlet and outlet
sides of filter (Figs. 13 or 14). For procedures, refer to
Fuel Tubes/Lines/Hoses and Clamps. Also refer to
Quick-Connect Fittings. These can be found in the
Fuel Delivery System section of this group.
(6) Remove retaining strap bolt.
(7) Remove filter from vehicle.
INSTALLATION
CAUTION: The ends of the fuel filter are marked for
correct installation. Install filter with the end marked
IN towards fuel tank and the end marked OUT to-
wards engine.
Fig. 13 Fuel Filter and ShieldÐYJ Models
Fig. 14 Fuel FilterÐXJ Models
14 - 8 FUEL SYSTEMJ

tainer. Pull the fitting from the fuel system compo-
nent being serviced. The plastic retainer will remain
on the component being serviced after fitting is dis-
connected. The O-rings and spacer will remain in the
quick-connect fitting connector body.
(5) Inspect the quick-connect fitting body and com-
ponent for damage. Replace as necessary.
CAUTION: When the quick-connect fitting was dis-
connected, the plastic retainer will remain on the
component being serviced. If this retainer must be
removed, very carefully release the retainer from
the component with two small screwdrivers. After
removal, inspect the retainer for cracks or any dam-
age.
(6) Prior to connecting the quick-connect fitting to
component being serviced, check condition of fitting
and component. Clean the parts with a lint-free
cloth. Lubricate them with clean engine oil.
(7) Insert the quick-connect fitting to the compo-
nent being serviced and into the plastic retainer.
When a connection is made, a click will be heard.
(8) Verify a locked condition by firmly pulling on
fuel tube and fitting (15-30 lbs.).
(9) Connect negative cable to battery.
(10) Start engine and check for leaks.
PLASTIC RETAINER RING TYPE FITTING
This type of fitting can be identified by the use of a
full-round plastic retainer ring (Fig. 19) usually
black in color.
CAUTION: The interior components (O-rings, spac-
ers, retainers) of this type of quick-connect fitting
are not serviced separately. Do not attempt to re-
pair damaged fittings or fuel lines/tubes. If repair is
necessary, replace the complete fuel tube/quick-
connect fitting assembly.
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING ANY FUEL SYSTEM HOSES,
FITTINGS OR LINES, THE FUEL SYSTEM PRES-
SURE MUST BE RELEASED. REFER TO THE FUEL
PRESSURE RELEASE PROCEDURE IN THIS
GROUP.
DISCONNECTION/CONNECTION
(1) Disconnect negative battery cable from the bat-
tery.
(2) Perform the fuel pressure release procedure.Refer to the Fuel Pressure Release Procedure in this
section.
(3) Clean the fitting of any foreign material before
disassembly.
(4) To release the fuel system component from the
quick-connect fitting, firmly push the fitting towards
the component being serviced while firmly pushing
the plastic retainer ring into the fitting (Fig. 19).
With the plastic ring depressed, pull the fitting from
the component.The plastic retainer ring must be
pressed squarely into the fitting body. If this re-
tainer is cocked during removal, it may be dif-
ficult to disconnect fitting. Use an open-end
wrench on the shoulder of the plastic retainer
ring to aid in disconnection.
After disconnection, the plastic retainer ring will
remain with the quick-connect fitting connector body.
(5) Inspect fitting connector body, plastic retainer
ring and fuel system component for damage. Replace
as necessary.
(6) Prior to connecting the quick-connect fitting to
component being serviced, check condition of fitting
and component. Clean the parts with a lint-free
cloth. Lubricate them with clean engine oil.
(7) Insert the quick-connect fitting into the compo-
nent being serviced until a click is felt.
(8) Verify a locked condition by firmly pulling on
fuel tube and fitting (15-30 lbs.).
(9) Connect negative battery cable to battery.
(10) Start engine and check for leaks.
Fig. 19 Plastic Retainer Ring Type Fitting
JFUEL SYSTEM 14 - 11

REMOVALÐXJ MODELS
Perform the preceding Fuel System Pressure Re-
lease Procedure.
(1) Disconnect negative battery cable.
(2) Remove the fuel filler cap. Using an approved
portable gasoline siphon/storage tank, drain fuel
tank.
(3) Raise and support vehicle.
(4) Disconnect fuel fill hose and fill vent hose from
filler neck (Fig. 1).
(5) Disconnect fuel pump module wire connector.
Remove tie straps securing connector harness to fuel
supply and return tubes.
WARNING: WRAP SHOP TOWELS AROUND FUEL
HOSES TO ABSORB ANY FUEL SPILLAGE DURING
FUEL TANK REMOVAL.
(6) Disconnect fuel tank vent hose from vent tube.
(7) Disconnect fuel supply and return hoses from
tubes.
(8) If equipped, remove skid plate (Fig. 2).
(9) Remove fuel tank shield (Fig. 3).
(10) Center a transmission jack under the fuel tank.
(11) Remove support strap nuts. Move straps away
from tank (Fig. 3).
(12) Lower fuel tank on transmission jack.
INSTALLATIONÐXJ MODELS
(1) Raise fuel tank into position. Connect fuel fill
hose and vent hose to filler neck and tighten clamps.
(2) Wrap support straps around tank and over studs.
Tighten strap nuts to 11.3 Nzm (100 in. lbs.) torque.
(3) Remove transmission jack.(4) Install tank shield.
(5) If equipped, install tank skid plate.
(6) Connect vent hose to vent tube.
(7) Connect fuel supply hose to supply tube and
fuel return hose to return tube. Tighten hose clamps.
(8) Connect fuel pump module wire connector to
harness connector. Secure fuel pump module wire
harness to fuel tubes with tie straps.
(9) Lower vehicle.
(10) Fill fuel tank. Install filler cap.
(11) Connect negative battery cable to battery.
(12) Start vehicle and inspect for leaks.
Fig. 1 Filler Neck HosesÐXJ Models
Fig. 2 Skid PlateÐXJ Models
Fig. 3 Fuel Tank Remove/InstallÐXJ Models
JFUEL SYSTEM 14 - 13

REMOVALÐYJ MODELS
WARNING: EXTINGUISH ALL TOBACCO SMOKING
PRODUCTS BEFORE SERVICING THE FUEL SYS-
TEM. KEEP OPEN FLAME AWAY FROM FUEL SYS-
TEM COMPONENTS.
(1) Disconnect negative battery cable.
(2) Remove the fuel filler cap. Using an approved por-
table gasoline siphon/storage tank, drain fuel tank.
(3) Raise and support vehicle.
(4) Using a small straight blade screwdriver, pull
back the stems of the push clips that secure the fuel
filler neck shroud (located at bottom of left rear
wheel well) in place (Fig. 4). This unlocks the push
clip allowing them to be removed by pulling assem-
bly out of shroud. Remove shroud.
(5) Disconnect fuel fill hose and fill vent hose from
filler neck (Fig. 5).
WARNING: WRAP SHOP TOWELS AROUND FUEL
HOSES TO ABSORB ANY FUEL SPILLAGE DURING
FUEL TANK REMOVAL.(6) Disconnect fuel tank vent hose from vent tube.
Disconnect fuel supply and return hoses from tubes
(Fig. 6).
The fuel tank and skid plate are removed as an as-
sembly.
(7) Centrally position a transmission jack under
skid plate/fuel tank assembly.
(8) Remove skid plate/fuel tank assembly mount-
ing nuts (Fig. 7).Do not loosen tank strap nuts.
(9) Lower the skid plate/fuel tank assembly
slightly and disconnect the gauge sender wire con-
nector.
(10) Lower the fuel tank on transmission jack.
(11) Remove tank strap nuts to remove tank from
skid plate.
Fig. 4 Fuel Filler Neck ShroudÐYJ Models
Fig. 5 Filler Neck HosesÐYJ Models
Fig. 6 Fuel Tank HosesÐYJ Models
Fig. 7 Fuel TankÐRemove/InstallÐYJ Models
14 - 14 FUEL SYSTEMJ

(3) Lower the vehicle.
PARK NEUTRAL SWITCH
Refer to Group 21, Transmissions for park neutral
switch service.
POWER STEERING PRESSURE SWITCHÐ2.5L
ENGINE ONLY
The power steering pressure switch is installed in
the power steering high pressure hose (Figs. 11 or
12).
REMOVAL
(1) Disconnect the electrical connector from the
power steering pressure switch.
(2) Place a small container or shop towel beneath
the switch to collect any excess fluid.
(3) Remove the switch.
INSTALLATION
(1) Install the power steering switch.
(2) Connect the electrical connector to the switch.(3) Check power steering fluid and add as neces-
sary.
(4) Start the engine and again check power steer-
ing fluid. Add fluid if necessary.
POWERTRAIN CONTROL MODULE (PCM)
On XJ models, the PCM is located in the engine
compartment next to the air cleaner (Fig. 13). On YJ
models, the PCM is located in the engine compart-
ment behind the windshield washer fluid reservoir
(Fig. 14).
REMOVAL
(1) Disconnect the negative battery cable at the
battery.
(2) YJ Models Only: Remove the windshield
washer fluid tank.
(3) Loosen the 60-Way connector mounting bolt
(Figs. 13 or 14).
(4) Remove the electrical connector by pulling
straight back.
(5) Remove the three PCM mounting bolts.
(6) Remove PCM.
Fig. 11 Power Steering Pressure SwitchÐYJ Models
Fig. 12 Power Steering Pressure SwitchÐXJ Models
Fig. 13 PCM LocationÐXJ Models
Fig. 14 PCM LocationÐYJ Models
14 - 58 FUEL SYSTEMJ

BRAKE BLEEDINGÐBRAKE FLUID AND LEVELÐBRAKELINES AND HOSES
INDEX
page page
Brake BleedingÐXJ/YJ with ABS Brakes....... 14
Brake BleedingÐXJ/YJ with Standard Brakes . . . 13
Brake Fluid Contamination.................. 13
Brake Fluid Level........................ 13Brakeline Charts......................... 15
Brakelines and Hoses..................... 15
Combination Valve....................... 15
Recommended Brake Fluid................. 13
RECOMMENDED BRAKE FLUID
The only brake fluid recommended for Jeep vehi-
cles with standard or antilock brakes, is Mopar brake
fluid, or an equivalent fluid meeting SAE J1703 and
DOT 3 standards.
Use new brake fluid only to top off the master
cylinder or refill the system. Never use re-
claimed fluid, fluid not meeting the SAE/DOT
standards or fluid from an unsealed container.
Do not use fluid from any container that has
been left open for any length of time. Fluid in
open containers can absorb moisture.
BRAKE FLUID LEVEL
Always clean the master cylinder and cover before
checking fluid level. If not cleaned, dirt from the
cover could enter the fluid. Also check the cover seal
and replace it if torn or distorted.
Correct fluid level is to within 6 mm (1/4 in.) of the
reservoir rim, or to the fill mark on models with a
plastic reservoir. Refer to the Antilock Brake section
for fluid levels on models equipped with ABS brakes.
BRAKE FLUID CONTAMINATION
Oil in the fluid will cause brake system rubber
seals to soften and swell. The seals may also become
porous and begin to deteriorate.
If fluid contamination is suspected, drain off a sam-
ple from the master cylinder. A suction gun or simi-
lar device can be used for this purpose.
Empty the drained fluid into a glass container.
Contaminants in the fluid will cause the fluid to sep-
arate into distinct layers. If contamination has oc-
curred, the system rubber seals, hoses and cups must
be replaced and the system thoroughly flushed with
clean brake fluid.
BRAKE BLEEDINGÐXJ/YJ WITH STANDARD
BRAKES
Use Mopar DOT 3 brake fluid, or an equivalent
meeting SAE/DOT standards J1703-F and DOT 3, to
fill and bleed the system.
On standard brake models, bleeding can be per-
formed either manually or with pressure equipment.
However, if pressure equipment is used, it will be
necessary to hold the front brake metering valveopen in order to bleed the front brakes. The valve
can be held open with a tension clip tool or by hand.
It will also be necessary that a suitable size pressure
tank hose adapter be available for use on the master
cylinder.
MANUAL BLEEDING PROCEDURE
(1) If master cylinder has been overhauled or a
new cylinder will be installed, bleed cylinder on
bench before installation. This shortens time needed
to bleed system and ensures proper cylinder opera-
tion.
(2) Wipe master cylinder reservoir and cap clean
with shop towels.
(3) Remove cover and fill master cylinder reservoir
with Mopar, or equivalent DOT 3 brake fluid.
(4) Open all caliper and wheel cylinder bleed
screws.
(5) Close bleed screws after fluid begins flowing
from each bleed screw.
(6) Top off master cylinder reservoir again.
(7) Use following bleed sequence:
²master cylinder
²right rear
²left rear
²right front
²left front
(8) Observe following brake bleeding precautions:
²Do not pump brake pedal at any time while bleed-
ing. Air in system will be compressed into small bub-
bles that are distributed throughout hydraulic
system. This will make a second and third bleeding
operation necessary.
²Bleed only one wheel brake unit at a time and use
a bleed hose to bleed each wheel brake unit (Fig. 7).
²Attach one end of bleed hose to bleed screw and in-
sert opposite end in glass container partially filled
with brake fluid (Fig. 7). Glass container makes it
easier to see air bubbles as they exit the bleed hose.
²Be sure end of bleed hose is immersed in fluid. Im-
mersing hose end in fluid prevents air from being
drawn back into cylinder and brakeline.
(9) Bleed master cylinder first. Have helper oper-
ate brake pedal while bleeding each master cylinder
fluid outlet line.
JBRAKES 5 - 13

STANDARD MASTER CYLINDER
INDEX
page page
General Service Information................ 20
Master Cylinder Installation................. 20Master Cylinder Overhaul.................. 20
Master Cylinder Removal.................. 20
GENERAL SERVICE INFORMATION
The service information in this section covers the
standard (non-ABS) master cylinder only. The center
feed master cylinder used with the ABS system is
covered in the antilock brake component service sec-
tion.
MASTER CYLINDER REMOVAL
(1) Disconnect brake lines at master cylinder.
(2) Remove cylinder mounting nuts and remove
master cylinder.
(3) Remove cylinder cover and drain fluid.
MASTER CYLINDER INSTALLATION
(1) Bleed master cylinder on bench before installa-
tion. Refer to overhaul assembly procedure in this
section for bleeding method.
(2) Install cylinder on brake booster studs and in-
stall cylinder attaching nuts. Tighten nuts to 21 NIm
(15 ft. lbs.).
(3) Connect brakelines to cylinder.
(4) Fill and bleed brake system.
MASTER CYLINDER OVERHAUL
CYLINDER DISASSEMBLY
(1) Remove cylinder cover and drain fluid.
(2) Examine cylinder cover seal. Discard seal if
torn or distorted.
(3) Clamp cylinder in vise (Fig. 1).
(4) Press primary piston inward with wood dowel
or phillips screwdriver and remove snap ring (Fig. 2).
(5) Remove and discard primary piston (Fig. 3).
Piston is serviced only as an assembly.
(6) Remove secondary piston (Fig. 4). Apply air
pressure through rear outlet port to ease piston out
of bore. Cover small ports at bottom of rear reservoir
with towel to prevent air leakage.
(7) Discard secondary piston. Do not disassemble
piston as components are only serviced as assembly.
CLEANING AND INSPECTION
Clean the cylinder with Mopar brake cleaning sol-
vent or clean brake fluid. Remove cleaning residue
with compressed air.
Inspect the cylinder bore. A light discoloration of
the bore surface is normal and acceptable but only if
the surface is in good condition.Replace the cylinder if the bore is scored, corroded,
or pitted.Do not hone the cylinder bore in an at-
tempt to restore the surface. Replace the cylin-
der if the bore is corroded or if doubt exists
about cylinder bore condition.
Fig. 1 Cylinder Mounted In Vise
Fig. 2 Removing/Installing Piston Snap Ring
5 - 20 BRAKESJ

(9) Remove inboard shoe. Grasp ends of shoe and
tilt shoe outward to release springs from caliper pis-
ton (Fig. 8). Then remove shoe from caliper.
(10) Support caliper on box, mechanics stool, or se-
cure it to nearby suspension part with wire.Do not
allow brake hose to support caliper weight.
(11) Wipe caliper off with shop rags or towels.Do
not use compressed air. Compressed air can un-
seat dust boot and force dirt into piston bore.
(12) Inspect condition of caliper piston dust boot
(Fig. 9). Overhaul caliper if there is evidence of leak-
age past piston and dust boot. Then inspect caliper
bushings and boots (Fig. 9). Replace boots if torn or
cut. If bushings or boots are damaged, replace them.
DISC BRAKESHOE INSTALLATION
(1) Clean brakeshoe mounting ledge slide surfaces
of steering knuckle with wire brush. Then apply
light coat of Mopar multi-mileage grease to slide sur-
faces (Fig. 10).
(2) Lubricate caliper mounting bolts and bushings
(Fig. 10). Use GE 661 or Dow 111 silicone grease.(3) Keep new or original brakeshoes in sets.Do
not interchange them.
(4) Install inboard shoe in caliper (Fig. 11). Be
sure shoe retaining springs are fully seated in caliper
piston.
(5) Install outboard shoe in caliper (Fig. 12). Start
one end of shoe in caliper. Rotate shoe downward and
into place until shoe locating lugs and shoe spring
are seated.
(6) Verify that locating lugs on outboard shoe are
seated in caliper (Fig. 6).
(7) Install caliper. Position notches at lower end of
brakeshoes on bottom mounting ledge (Fig. 13). Then
install caliper over rotor and seat upper ends of
brakeshoes on top mounting ledge (Fig. 11).
CAUTION: Before securing the caliper, be sure the
caliper brake hose is not twisted, kinked or touch-
ing any chassis components. Also be sure the hose
is clear of all suspension and steering components.
Loosen and reposition the hose if necessary.
Fig. 7 Removing Outboard Brakeshoe
Fig. 8 Removing Inboard Brakeshoe
Fig. 9 Caliper Dust Boots And Bushing Locations
Fig. 10 Caliper Lubrication Points
5 - 26 BRAKESJ

(8) Install and tighten caliper mounting 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 will contact the inboard
brakeshoe causing a partial apply condition. Refer
to Figure 14 for required caliper bolt length.
(9) Install wheels. Tighten lug nuts to 102 Nzm (75
ft. lbs.) torque.
(10) Pump brake pedal until caliper pistons and
brakeshoes are seated.
(11) Top off brake fluid level if necessary. Use Mo-
par brake fluid or equivalent meeting SAE J1703
and DOT 3 standards only.
CALIPER REMOVAL
(1) Raise vehicle and remove front wheels.
(2) Remove caliper mounting bolts (Fig. 4).(3) Rotate caliper rearward by hand or with pry
tool (Fig. 5). Then rotate caliper and brakeshoes off
mounting ledges.
(4) Remove caliper hose fitting bolt and disconnect
front brake hose at caliper. Discard fitting bolt wash-
ers. They are not reusable and should be replaced.
(5) Remove caliper from vehicle.
CALIPER DISASSEMBLY
(1) Remove brakeshoes from caliper.
(2) Pad interior of caliper with minimum, 2.54 cm
(1 in.) thickness of shop towels or rags (Fig. 15). Tow-
els are needed to protect caliper piston during re-
moval.
(3) Remove caliper piston withshort burstsof low
pressure compressed air. Direct air through fluid in-
let port and ease piston out of bore (Fig. 16).
Fig. 11 Installing Inboard Brakeshoe
Fig. 12 Installing Outboard Brakeshoe
Fig. 13 Caliper Installation
Fig. 14 Caliper Mounting Bolt Dimensions
JBRAKES 5 - 27

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. In addition, NEVER attempt to
catch the piston as it leaves the bore. This will re-
sult in personal injury.
(4) Remove caliper piston dust boot (Fig. 17). Col-
lapse boot with suitable tool and remove and discard
boot.
(5) Remove and discard caliper piston seal with
wood or plastic tool (Fig. 18). Do not use metal tools
as they will scratch piston bore.
(6) Remove caliper mounting bolt bushings and
boots (Fig. 19).
CALIPER CLEANING AND INSPECTION
Clean the caliper and piston with Mopar brake
cleaner, clean brake fluid, or denatured alcohol only.
Do not use gasoline, kerosene, thinner, or similar sol-
vents. These products leave a residue that will dam-
age pistons and seals.
Wipe the caliper and piston dry with lint free tow-
els or use low pressure compressed air.
Inspect the piston and piston bore. Replace the cal-
iper if the bore is corroded, rusted, pitted, or scored.
Fig. 15 Padding Caliper Interior To Protect Piston
During Removal
Fig. 16 Removing Caliper Piston
Fig. 17 Removing Caliper Piston Dust Boot
Fig. 18 Removing Caliper Piston Seal
Fig. 19 Caliper Slide Bushing And Boot
5 - 28 BRAKESJ