(2) Remove nut from pedal shaft.
(3) Slide pedal shaft out and remove brake pedal.
(4) Remove pedal bushings (Fig. 54) if they are to
be replaced.
REMOVAL - ADJUSTABLE PEDALS
NOTE: If possible put the pedals in the full forward
position.
(1) Disconnect the negative battery cable.
(2) Remove the cluster bezel (Refer to 23 - BODY/
INSTRUMENT PANEL/CLUSTER BEZEL - REMOV-
AL).
(3) Remove the steering column opening cover
(Refer to 23 - BODY/INSTRUMENT PANEL/STEER-
ING COLUMN OPENING COVER - REMOVAL).
(4) Disconnect the module electrical connector.
(5) Remove the brake light switch.
(6) Disconnect the booster rod clip (Fig. 53).
(7) Disconnect the accelerator cable from the
pedal.
(8) Lock the steering wheel into place.
(9) Remove the lower steering shaft pinch bolt
(Fig. 56).
(10) Separate the lower shaft coupler and push for-
ward (Fig. 56).
(11) Remove the two pedal bracket upper nuts
(Fig. 55).
(12) Remove the brake booster nuts (Fig. 56).
(13) Remove the accelerator pedal nuts (Fig. 57).(14) Remove the ICU mounting bracket nuts and
bolts and move the ICU and booster forward this will
allow enough clearance to remove the adjustable
pedal bracket from over the booster push rod.
(15) Remove the pedal from the vehicle (Fig. 56).
(16) Transfer the module if needed.
Fig. 54 Pedal Bushings
1 - BUSHING
2 - BUSHING
3 - SHAFT NUT
4 - PEDAL SHAFT
Fig. 55 UPPER MOUNTING NUTS
1 - UPPER MOUNTING STUDS
2 - ACCELERATOR MOUNTING STUDS
3 - UPPER MOUNTING NUT
4 - MOTOR
5 - ADJUSTABLE PEDAL BRACKET
Fig. 56 ADJUSTABLE PEDAL BRACKET
1 - BRAKE LIGHT SWITCH
2 - STEERING COLUMN
3 - ACCELERATOR PEDAL
4 - ADJUSTABLE PEDALS MOUNTING BRACKET
5 - BRAKE PEDAL
6 - MOTOR MOUNTING BRACKET
7 - BRAKE BOOSTER MOUNTING NUTS
(4)
WJBRAKES - BASE 5 - 27
PEDAL (Continued)
(8) Remove the park brake lever mounting nuts
and console bracket (Fig. 80).
(9) Lift the lever assembly off the mounting studs
and pull the front cable out of the lever bracket.
INSTALLATION
(1) Install the lever assembly on the mounting
studs while feeding the front cable into the lever
bracket.
(2) Install the console bracket (Fig. 80) and mount-
ing nuts.
(3) Engage the front cable end to the lever.
(4) Connect parking brake switch wire connector.
(5) Pull on the lever to release the lock out spring.
(6) Install center console,(Refer to 23 - BODY/IN-
TERIOR/FLOOR CONSOLE - INSTALLATION).
(7) Fold down the rear carpet cover and rear seat.
SHOES
REMOVAL
(1) Lock out park brake lever (Fig. 81).
(2) Raise vehicle.
(3) Remove rear wheel and tire assembly.
(4) Remove caliper and anchor as an assembly.
(5) Remove rubber access plug from back of rear
disc brake splash shield.
(6) If necessary retract parking brake shoes with
brake adjuster tool (Fig. 82). Position tool at top of
star wheel and rotate wheel.
(7) Remove rotor from axle hub flange.
(8) Remove the lower shoe to shoe spring/adjuster
spring with needle nose pliers (Fig. 83).
(9) Remove the upper shoe to shoe spring/return
spring with brake pliers (Fig. 84).(10) Remove shoe hold-down clips and pins (Fig.
85). Clip is held in place by pin which fits in clip
notch. To remove clip, first push clip ends together
and slide clip until head of pin clears narrow part of
notch. Then remove clip and pin.
(11) Remove shoes and adjuster.
INSTALLATION
(1) Install shoes on splash shield with hold down
clips and pins. Be sure shoes are properly engaged in
the park brake actuator.
(2) Lubricate and install adjuster screw assembly.
Be sure notched ends of screw assembly are properly
seated on shoes and that star wheel is aligned with
access hole in shield.
Fig. 80 Parking Brake Lever Mounting
1 - MOUNTING NUT
2 - PARK BRAKE LEVER
Fig. 81 Lock Out Spring
1 - LOCK OUT SPRING
Fig. 82 Retracting Parking Brake Shoes
1 - ACCESS HOLE
2 - BRAKE ADJUSTING TOOL
3 - SPLASH SHIELD
WJBRAKES - BASE 5 - 39
LEVER (Continued)
²SLIGHT TAIL WIND AT IDLE
²SLOW TRAFFIC
²TRAFFIC JAMS
²HIGH SPEED
²STEEP GRADES
Driving techniques that avoid overheating are:
²Idle with A/C off when temperature gauge is at
end of normal range.
²Increase engine speed for more air flow is recom-
mended.(1) TRAILER TOWING:
Consult Trailer Towing section of owners manual.
Do not exceed limits.
(2) AIR CONDITIONING; ADD-ON OR AFTER
MARKET:
A maximum cooling package should have been
ordered with vehicle if add-on or after market A/C is
installed. If not, maximum cooling system compo-
nents should be installed for model involved per
manufacturer's specifications.
(3) RECENT SERVICE OR ACCIDENT REPAIR:
Determine if any recent service has been per-
formed on vehicle that may effect cooling system.
This may be:
²Engine adjustments (incorrect timing)
²Slipping engine accessory drive belt(s)
²Brakes (possibly dragging)
²Changed parts. Incorrect water pump, or pump
rotating in wrong direction due to belt not correctly
routed
²Reconditioned radiator or cooling system refill-
ing (possibly under filled or air trapped in system).
NOTE: If investigation reveals none of the previous
items as a cause for an engine overheating com-
plaint, refer to following Cooling System Diagnosis
charts.
These charts are to be used as a quick-reference
only. Refer to the group text for information.
Fig. 4 Spring Clamp Size Location
1 - SPRING CLAMP SIZE LOCATION
7 - 4 COOLINGWJ
COOLING (Continued)
CONDITION POSSIBLE CAUSES CORRECTION
7. Water pump impeller loose on
shaft.7. Check water pump and replace as
necessary. (Refer to 7 - COOLING/ENGINE/
WATER PUMP - DIAGNOSIS AND
TESTING).
8. Loose accessory drive belt. (water
pump slipping)8. (Refer to 7 - COOLING/ACCESSORY
DRIVE/DRIVE BELTS - DIAGNOSIS AND
TESTING). Check and correct as necessary.
9. Air leak on the suction side of the
water pump allows air to build up in
cooling system causing thermostat
to open late.9. Locate leak and repair as necessary.
PRESSURE CAP IS
BLOWING OFF STEAM
AND/OR COOLANT TO
COOLANT TANK.
TEMPERATURE GAUGE
READING MAY BE
ABOVE NORMAL BUT
NOT HIGH. COOLANT
LEVEL MAY BE HIGH IN
COOLANT RESERVE/
OVERFLOW TANK1. Pressure relief valve in radiator
cap is defective.1. Check condition of radiator cap and cap
seals. (Refer to 7 - COOLING/ENGINE/
RADIATOR PRESSURE CAP - DIAGNOSIS
AND TESTING). Replace cap as necessary.
COOLANT LOSS TO THE
GROUND WITHOUT
PRESSURE CAP
BLOWOFF. GAUGE
READING HIGH OR HOT1. Coolant leaks in radiator, cooling
system hoses, water pump or
engine.1. Pressure test and repair as necessary.
(Refer to 7 - COOLING - DIAGNOSIS AND
TESTING).
DETONATION OR
PRE-IGNITION (NOT
CAUSED BY IGNITION
SYSTEM). GAUGE MAY
OR MAY NOT BE
READING HIGH1. Engine overheating. 1. Check reason for overheating and repair
as necessary.
2. Freeze point of coolant not
correct. Mixture is too rich or too
lean.2. Check coolant concentration. (Refer to 7 -
COOLING/ENGINE/COOLANT -
DESCRIPTION) and adjust ratio as required.
HOSE OR HOSES
COLLAPSE WHILE
ENGINE IS RUNNING1. Vacuum created in cooling system
on engine cool-down is not being
relieved through coolant reserve/
overflow system.1. (a) Radiator cap relief valve stuck. (Refer
to 7 - COOLING/ENGINE/RADIATOR
PRESSURE CAP - DIAGNOSIS AND
TESTING). Replace if necessary
(b) Hose between coolant reserve/overflow
tank and radiator is kinked. Repair as
necessary.
(c) Vent at coolant reserve/overflow tank is
plugged. Clean vent and repair as necessary.
(d) Reserve/overflow tank is internally
blocked or plugged. Check for blockage and
repair as necessary.
7 - 8 COOLINGWJ
COOLING (Continued)
SERPENTINE DRIVE BELT DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
RIB CHUNKING (ONE OR MORE
RIBS HAS SEPARATED FROM
BELT BODY)1. Foreign objects imbedded in pulley
grooves.1. Remove foreign objects from
pulley grooves. Replace belt.
2. Installation damage. 2. Replace belt.
RIB OR BELT WEAR 1. Pulley(s) misaligned. 1. Align pulley(s).
2. Abrasive environment. 2. Clean pulley(s). Replace belt if
necessary.
3. Rusted pulley(s). 3. Clean rust from pulley(s).
4. Sharp or jagged pulley groove tips. 4. Replace pulley.
5. Rubber deteriorated. 5. Replace belt.
LONGITUDINAL BELT
CRACKING (CRACKS BETWEEN
TWO RIBS)1. Belt has mistracked from pulley
groove.1. Replace belt.
2. Pulley groove tip has worn away
rubber to tensile member.2. Replace belt.
BELT SLIPS 1. Belt slipping because of insufficient
tension.1. Replace automatic belt tensioner.
2. Belt routed 2. Verify belt routing.
incorrectly
3. Incorrect belt. 3. Replace belt.
4. Belt or pulley subjected to
substance (belt dressing, oil ethylene
glycol) that has reduced friction.4. Replace belt and clean pulleys.
5. Driven component bearing failure. 5. Replace faulty component
bearing.
6. Belt glazed and hardened from
heat and excessive slippage.6. Replace belt.
ªGROOVE JUMPING9(BELT
DOES NOT MAINTAIN CORRECT
POSITION ON PULLEY)1. Belt tension either too high or too
low.1. Replace automatic belt tensioner.
2. Belt routed 2. Verify belt routing.
incorrectly.
3. Incorrect belt. 3. Replace belt.
4. Pulley(s) not within design
tolerance.4. Replace pulley(s).
5. Foreign object(s) in grooves. 5. Remove foreign objects from
grooves.
6. Pulley misalignment. 6. Check and replace.
7. Belt cord line is broken. 7. Replace belt.
7 - 18 ACCESSORY DRIVEWJ
DRIVE BELTS - 4.0L (Continued)
SERPENTINE DRIVE BELT DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
RIB CHUNKING (ONE OR MORE
RIBS HAS SEPARATED FROM
BELT BODY)1. Foreign objects imbedded in pulley
grooves.1. Remove foreign objects from
pulley grooves. Replace belt.
2. Installation damage. 2. Replace belt.
RIB OR BELT WEAR 1. Pulley(s) misaligned. 1. Align pulley(s).
2. Abrasive environment. 2. Clean pulley(s). Replace belt if
necessary.
3. Rusted pulley(s). 3. Clean rust from pulley(s).
4. Sharp or jagged pulley groove tips. 4. Replace pulley.
5. Rubber deteriorated. 5. Replace belt.
LONGITUDINAL BELT
CRACKING (CRACKS BETWEEN
TWO RIBS)1. Belt has mistracked from pulley
groove.1. Replace belt.
2. Pulley groove tip has worn away
rubber to tensile member.2. Replace belt.
BELT SLIPS 1. Belt slipping because of insufficient
tension.1. Replace automatic belt tensioner.
2. Belt routed 2. Verify belt routing.
incorrectly
3. Incorrect belt. 3. Replace belt.
4. Belt or pulley subjected to
substance (belt dressing, oil ethylene
glycol) that has reduced friction.4. Replace belt and clean pulleys.
5. Driven component bearing failure. 5. Replace faulty component
bearing.
6. Belt glazed and hardened from
heat and excessive slippage.6. Replace belt.
ªGROOVE JUMPING9(BELT
DOES NOT MAINTAIN CORRECT
POSITION ON PULLEY)1. Belt tension either too high or too
low.1. Replace automatic belt tensioner.
2. Belt routed 2. Verify belt routing.
incorrectly.
3. Incorrect belt. 3. Replace belt.
4. Pulley(s) not within design
tolerance.4. Replace pulley(s).
5. Foreign object(s) in grooves. 5. Remove foreign objects from
grooves.
6. Pulley misalignment. 6. Check and replace.
7. Belt cord line is broken. 7. Replace belt.
WJACCESSORY DRIVE 7 - 21
DRIVE BELTS - 4.7L (Continued)
²Fan control valve
²Two stage G-rotor hydraulic drive
The hydraulic fan and drive is not serviceable.
Therefore any failure of the fan blade, hydraulic fan
drive or fan shroud requires replacement of the fan
module because the fan blade and hydraulic fan drive
are matched and balanced as a system and servicing
either separately would disrupt this balance.
For hydraulic fluid routing information refer to
(Fig. 5).
CAUTION: Do not attempt to service the hydraulic
cooling fan or fan drive separately replace the cooling
module as an assembly. Failure to do so may cause
severe damage to the hydraulic cooling fan assembly.
OPERATION
The hydraulic radiator cooling fan used on the
Grand Cherokee with the 4.7L engine replaces both
the electric fan and the engine driven mechanical
fan. The use of this hydraulic fan provides the 4.7L
equipped Grand Cherokee with heavy trailer tow
capability while at the same time reducing unneces-
sary power drain on both the engine and the vehicles
electrical system.
HYDRAULIC FAN STRATEGY
The hydraulic radiator cooling fan is controlled by
the JTEC. A PWM (Pulse With Modulated) signal
from the JTEC controls the fan from 0 to 100% of the
available fan speed. There are four inputs to the
JTEC that determine what speed percentage of fan is
required by the vehicle. These inputs are:
²Engine Coolant Temperature
²Transmission Oil Temperature
²Battery Temperature
²A/C System Pressure
By monitoring these four parameters, the JTEC
can determine if cooling airflow is required. If airflow
is required, the JTEC will slowly ramp up (speed up)
the fan speed until the parameter(s) are under con-
trol. Once the temperature or pressure is reduced to
within operating parameters the fan will ramp up,
ramp down, or hold its speed to maintain the temper-
ature / pressure requirements.
NOTE: Even if the JTEC is not requesting fan on
operation the fan blade will usually spin between
100 and 500 RPM when the vehicle is at idle. This is
due to a controlled minimum oil flow requirement
through the fan drive motor.
ACTIVATING THE HYDRAULIC FAN WITH THE DRB
Under the Engine Systems test heading, there is a
subheading. ªHydraulic fan solenoid testº, that has
the selections, on /off. Activating the fan with the
DRB will run the fan at 100% duty cycle, which will
help troubleshoot any system problems, and also help
with the deaeration procedure.
NOTE: Engine must be running to activate the fan
with the DRB.
RADIATOR COOLING FAN HYDRAULIC FLUID PATH
Hydraulic fluid is pumped through the power
steering pump, from the pump the fluid travels
though a high pressure delivery line to the fan drive
motor. As fluid is diverted through the G-rotors, rota-
tional motion is created as fluid moves from the high-
pressure (inlet) side of the motor to the low-pressure
(outlet) side. Fluid exiting the drive motor is divided
into two paths. Path one continues through a high
pressure delivery line to the vehicles steering gear to
provide steering assist. and path two sends fluid
back to the power steering pump through a low pres-
sure line. Fluid exits the steering gear under low
pressure and travels through a low pressure line to
the power steering fluid cooler to be cooled before
being returned back the the power steering fluid res-
ervoir (Fig. 5).
Fig. 4 HYDRAULIC RADIATOR COOLING FAN AND
FAN DRIVE
1 - POWER STEERING FLUID COOLER
2 - RADIATOR
3 - HIGH PRESSURE LINE FROM STEERING GEAR PUMP TO
HYDRAULIC FAN MOTOR
4 - HYDRAULIC FAN MOTOR
5 - HIGH PRESSURE LINE FROM HYDRAULIC FAN MOTOR TO
STEERING GEAR
6 - FAN SHROUD
7 - 28 ENGINEWJ
RADIATOR FAN - 4.7L (Continued)
FAN DRIVE VISCOUS CLUTCH
- 4.0L
DESCRIPTION
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.
CAUTION: If the viscous fan drive is replaced
because of mechanical damage, the cooling fan
blades should also be inspected. Inspect for fatigue
cracks, loose blades, or loose rivets that could
have resulted from excessive vibration. Replace fan
blade assembly if any of these conditions are
found. Also inspect water pump bearing and shaft
assembly for any related damage due to a viscous
fan drive malfunction.
The thermal viscous fan drive (Fig. 27) is a sili-
cone-fluid-filled coupling used to connect the fan
blades to the water pump shaft. The coupling allows
the fan to be driven in a normal manner. This is
done at low engine speeds while limiting the top
speed of the fan to a predetermined maximum level
at higher engine speeds.
An electrical cooling fan located in the fan shroud
aids in low speed cooling, It is designed to augment
the viscous fan, However, it does not replace the vis-
cous fan.
OPERATION
A thermostatic bimetallic spring coil is located on
the front face of the viscous fan drive unit (Fig. 27).
This spring coil reacts to the temperature of the radi-
ator discharge air. It engages 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 necessary,the fan will remain at
a reduced rpm regardless of engine speed. Nor-
mally less than three hundred (300) rpm.
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 to 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
reacts and the fan speed is reduced to the previous
disengaged speed.
DIAGNOSIS AND TESTINGÐVISCOUS FAN
DRIVE
If the fan assembly free-wheels without drag (the
fan blades will revolve more than five turns when
spun by hand), replace the fan drive. This spin test
must be performed when the engine is cool.
For the following test, the cooling system must be
in good condition. It also will ensure against exces-
sively high coolant temperature.
WARNING: 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
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR FAN. DO
NOT WEAR LOOSE CLOTHING.
Fig. 27 Viscous Fan Drive
1 - VISCOUS FAN DRIVE
2 - THERMOSTATIC SPRING
3 - MOUNTING NUT TO WATER PUMP HUB
7 - 40 ENGINEWJ