warning JEEP CHEROKEE 1994 Service Repair Manual

INTERIOR REARVIEW MIRROR SUPPORT
BRACKET REPLACEMENT
PREPARATION
(1) Mark reference lines for the mirror support
bracket on the outside of windshield glass with a wax
pencil.
(2) If the vinyl pad remained on the windshield
glass, soften and remove it with a heat gun.
(3) Clean the support bracket surface area on the
glass. Use a mild abrasive cleaning powder on a cloth
saturated with isopropyl (rubbing) alcohol.
(4) Lightly sand the contact surface on the support
bracket with fine grit sandpaper. Wipe bracket con-
tact surface clean with a paper towel and alcohol.
INSTALLATION
(1) Apply adhesive to the act surface on the sup-
port bracket according as follows:
²crush the vial in the plastic housing of the accel-
erator to saturate the felt applicator;
²remove the paper sleeve;
²apply a generous amount of accelerator to the con-
tact surface on the mirror support bracket;
²do not touch the support bracket contact surface
after the accelerator has been applied.
²allow the accelerator to dry for at least five min-
utes; and
(2) Apply accelerator to the support bracket con-
tact surface on the windshield glass. Allow the accel-
erator to dry for one minute.
(3) Install the mirror bracket on the windshield
glass follows:
²apply one drop of adhesive at the center of support
bracket contact surface on windshield glass;
²immediately apply an even coat of adhesive to the
contact surface on the support bracket;
²align the support bracket with the position refer-
ence lines on the windshield glass, then
²press and hold the support bracket in-place for at
least one minute.
Ensure that the mirror support bracket is
correctly aligned because the adhesive will
cure rapidly.
(4) Allow the adhesive to cure for 8-10 minutes,
then remove any residue adhesive with an alcohol-
dampened cloth.
(5) Allow the adhesive to cure for an additional
8-10 minutes before installing the mirror base on the
support bracket.
WINDSHIELD SERVICE INFORMATION
URETHANE ADHESIVE BONDING
The windshield glass is bonded to the body pinch-
weld flanges with urethane adhesive (Fig. 8). Thismethod of windshield installation complies with the
applicable Federal Motor Vehicle Safety Standards
(FMVSS).
WARNING: DO NOT OPERATE THE VEHICLE FOR
AT LEAST 24 HOURS AFTER WINDSHIELD INSTAL-
LATION. THE URETHANE ADHESIVE MAY NOT
PERFORM PROPERLY IN THE EVENT OF A COLLI-
SION IF IT IS NOT SUFFICIENTLY CURED. REFER
TO THE MANUFACTURER OF THE URETHANE BE-
ING USED FOR CURING TIME SPECIFICATIONS.
WHEN INSTALLING THE WINDSHIELD, DO NOT
USE URETHANE ADHESIVE IF THE EXPIRATION
DATE ON THE PRODUCT HAS PASSED. SAFETY
AND QUALITY ON THE REPAIR WOULD BE QUES-
TIONABLE.
REMOVAL/INSTALLATION METHODS
Windshield glass removal is accomplished by the
use of a razor knife and an electric hot knife to cut
through the urethane adhesive. This removal method
applies in all instances.
Depending on the circumstances, either one of two
windshield glass installation methods can be used:
²the short method, and
²the extended method.
The short method is used when the windshield
glass is removed intact, and the body opening and
the pinchweld flanges do not require repair.
The extended method must be used when the body
opening or a flange is damaged. The extended
method must also be used when urethane no longer
adheres to either the windshield glass or the pinch-
weld flanges.
WINDSHIELD GLASS REPLACEMENT
REMOVAL
(1) If the windshield glass short installation
method will be used, ensure that a bead of urethane
remains on the pinchweld flange.
Fig. 8 Windshield Glass Bonding With Urethane
JBODY COMPONENTSÐXJ VEHICLES 23 - 75

The following equipment and material are neces-
sary for body stripe/decal removal and installation:
²a commercial tape stripe/decal removal solution;
²a commercial adhesive removal solution;
²liquid dish detergent (for the wetting solution);
²a mixture of wetting solution;
²a commercial wax and silicone removal solution;
²isopropyl (rubbing) alcohol;
²a small squeegee (plastic or hard rubber);
²a water bucket and sponge;
²clean wiping rags or paper towels;
²a heat gun (or infra-red heat bulb);
²a wax pencil;
²a sharp knife, single edge razor blade or X-acto
knife;
²a pair of scissors; and
²a needle or pin.
A wetting solution assures a better bond between
the painted surface of the body and the tape stripe/
decal. Prepare a supply of wetting solution by mixing
two or three teaspoons of dish detergent with 1 gal-
lon of water.Do not use soap.
Too much detergent will reduce the effective-
ness of the mixture.
REMOVAL
The key to successful tape stripe/decal re-
moval is to apply heat to area and slowly peel
stripe/decal from panel.
(1) Clean the repaired surface, adjacent panels and
door openings as necessary.
(2) Start at one end of the tape stripe/decal and
apply heat with a heat gun. Slowly peel the stripe/
decal from the panel by pulling it back.Do not pull
the tape stripe/decal outward from the panel.
WARNING: USE THE TAPE STRIPE/DECAL RE-
MOVAL SOLUTION IN A WELL-VENTILATED AREA
ONLY.
(3) A commercial tape stripe/decal removal solution
can be used for stripe/decal removal at areas where a
heat gun is ineffective:
²mask-off the body panel area surrounding the tape
stripe/decal (Fig. 61);
²move the removal solution spray back and forth
across the complete length of the stripe/decal with a
smooth, steady motion;
²ensure that the complete stripe/decal is covered
with the solution;
²allow the stripe/decal removal solution to remain
on the stripe/decal for 20 minutes;
²after 20 minutes, peel stripe/decal away from the
flange and, starting at a corner, peel the stripe/decal
from the body (Fig. 62);
²if there is difficulty with peeling stripe/decal away
from body use a squeegee for stripe/decal removal
(Fig. 63); and²with the stripe/decal removed, scrape all the
stripe/decal removal solution from the panel surface
before proceeding.
Fig. 61 Stripe/Decal Removal Solution Application
Fig. 62 Body Stripe/Decal Removal
Fig. 63 Body Stripe/Decal Removal With A
Squeegee
23 - 154 BODY COMPONENTSÐXJ VEHICLESJ

WARNING: USE THE ADHESIVE REMOVAL SOLU-
TION IN A WELL-VENTILATED AREA ONLY.
(4) After the stripe/decal is removed, remove any
adhesive remaining on body with a removal solution.
(5) After 3 to 5 minutes, use a squeegee to remove
adhesive (Fig. 64).
(6) Remove the masking tape and mask from the
panel.
(7) Wipe the panel with a cloth with a general pur-
pose cleaning solution.
BODY PANEL SURFACE PREPARATION
(1) The area that will be covered by the tape
stripe/decal must be cleaned with an cleaning solu-
tion to remove any residue paint.
(2) Freshly painted surfaces must be thoroughly dry.
(3) Clean painted surface with a commercial wax
and silicone removal solution. Wipe surface with a
clean cloth and allow to dry.
REPLACEMENT ON ONE PANEL
For large tape stripes/decals, use a clean sponge
and apply ample wetting solution:
²to the adhesive side of the tape stripe/decal, and
²to the painted panel surface.
The wetting solution will permit ease of tape stripe/
decal movement when positioning it on the panel.
(1) Align a straight edge with the existing tape
stripe/decal ends and use a wax pencil to mark a line
on the panel (Fig. 65).
If applicable, the body panel character line
can be used as the tape stripe/decal alignment
reference.
(2) Position tape stripe/decal and carrier on panel
and mark the required length with a wax pencil.
(3) Cut the stripe/decal and carrier at the required
length with scissors.
(4) Position stripe/decal and carrier on panel and
hold it in-place with pieces masking tape (Fig. 66).
(5) Lift the bottom edge of the tape stripe/decal and
carrier, use the tape sections as hinges, and reverse the
position of the stripe/decal and carrier (Fig. 67).
Fig. 65 Stripe/Decal Alignment Reference Mark
Fig. 66 Tape Stripe/Decal and Carrier Retained On
Body Panel
Fig. 67 Tape Stripe/Decal and Carrier Reversed On
Body Panel
Fig. 64 Adhesive Removal With A Squeegee
JBODY COMPONENTSÐXJ VEHICLES 23 - 155

INSTALLATION
(1) Apply weatherstrip adhesive around the perim-
eter of the seal contact surface on the tailgate edge
(Fig. 87).
(2) Position the seal on the tailgate and press it
against the inner panel and flange.
(3) Install the seal retaining rivets (Fig. 87).
CAUTION: Do not apply graphite, brake fluid or wax
to the seal.
HARD TOP LIFTGATE GLASS
REMOVAL
(1) Disconnect the rear defroster/dome lamp wire
harness connectors.
(2) Remove the wiper motor cover. Disconnect the
wiper motor wire harness connector and the washer
fluid hose (Fig. 88).
(3) Remove the wiper arm and blade (Fig. 88).
WARNING: DO NOT REMOVE THE LIFTGATE SUP-
PORT RODS WITH THE LIFTGATE CLOSED. THE
SUPPORT ROD PISTONS ARE OPERATED BY HIGH
PRESSURE GAS AND COULD CAUSE PERSONAL
INJURY AND/OR VEHICLE DAMAGE IF THEY ARE
REMOVED WITH THE PISTONS COMPRESSED
(LIFTGATE CLOSED). ONCE REMOVED, DO NOT
ATTEMPT TO DISASSEMBLE OR REPAIR THE SUP-
PORT RODS.
(4) Open the tailgate (Fig. 89).(5) Remove the support rod cylinder retaining clips
at both ends of each support rod cylinder (Fig. 89)
(6) Pull the support rods off the ball studs (Fig.
89).
(7) Remove the liftgate glass hinge bolts (Fig. 89).
(8) Remove the liftgate glass from the hard top
(Fig. 89).
(9) Remove the weatherstrip seal (Fig. 89), if nec-
essary.
INSTALLATION
(1) Assemble the liftgate components, if necessary
(2) Position the liftgate glass in the hard top open-
ing and install the hinge bolts (Fig. 89). Do not
tighten the bolts.
(3) Adjust the liftgate glass to fit the hard top
opening.
(4) Tighten the hinge bolts to 11 Nzm (95 in-lbs)
torque.
(5) Position the support rod cylinders on the ball
studs (Fig. 89).
(6) Install the support rod cylinder retainer clips
(Fig. 89).
(7) Connect the wiper motor wire harness connec-
tor and the washer fluid hose. Install the wiper mo-
tor cover (Fig. 88).
(8) Install the wiper arm and blade (Fig. 88).
(9) Connect the rear window defroster/dome lamp
wire harness connectors.
DISASSEMBLY
(1) Remove retaining screws and the lower, inner
trim moulding from the latch panel (Fig. 90).
Fig. 87 Tailgate Weatherstrip Seal
Removal/InstallationFig. 88 Liftgate Wiper Motor
23 - 162 BODY COMPONENTSÐXJ VEHICLESJ

INSTRUMENT CLUSTER BEZEL
REMOVAL
(1) Remove the instrument cluster housing attach-
ing screws (Figs. 1, 2 and 3).
(2) Disconnect the switch illumination bulb from
instrument cluster (Fig. 4). Remove the housing from
the instrument panel (Fig. 1).
(3) Remove the bezel retaining screws.
(4) Disconnect the accessory switch, warning indi-
cator, rheostat and lamp wire harness connectors
from the bezel (Fig. 5).
(5) Remove the bezel from the instrument panel
(Fig. 6).
INSTALLATION
(1) Position bezel at the instrument panel and con-
nect accessory switch, warning indicator, rheostat
and lamp wire harness to bezel.
(2) Install the bezel screws. Tighten the screws to
3Nzm (24 in-lbs) torque.
(3) Position the instrument cluster housing on the
instrument panel (Fig. 1). Connect the switch illumi-
nation bulb socket to the instrument cluster housing
(Fig. 4).
(4) Install the attaching screws (Figs. 1, 2 and 3).
Tighten the screws to 3 Nzm (24 in-lbs) torque.
INSTRUMENT PANEL COMPONENTS
REMOVAL
(1) Remove the instrument cluster and gauge
housings from the instrument panel (Fig. 1). If appli-
cable, remove the bezel from the instrument panel.
(2) Remove the screws, disconnect the wire har-
ness connector(s) and remove the component from
the instrument panel.
INSTALLATION
(1) Position the component at the instrument
panel, connect the wire harness connector(s) and in-
stall screws. Tighten the screws to 3 Nzm (24 in-lbs)
torque.
(2) If removed, install the instrument cluster bezel
on the instrument panel. Install the instrument clus-
ter and gauge housings on the instrument panel (Fig.
1).
Fig. 4 Instrument Cluster Housing and Lamp
Fig. 5 Instrument Cluster Bezel
Fig. 6 Instrument Panel Components
JBODY COMPONENTSÐXJ VEHICLES 23 - 191

HEATING AND AIR CONDITIONING
CONTENTS
page page
CLIMATE CONTROL SYSTEMÐXJ VEHICLES . 22
CLIMATE CONTROL SYSTEMÐYJ VEHICLES . 37
COMPRESSOR OVERHAUL............... 17
GENERAL INFORMATION.................. 1SERVICE DIAGNOSISÐELECTRICAL........ 14
SERVICE DIAGNOSISÐMECHANICAL........ 8
TORQUE SPECIFICATIONS................ 45
GENERAL INFORMATION
INDEX
page page
A/C Operation............................ 1
Compressor Oil Level...................... 6
Pressure Gauge and Manifold Assembly........ 2
Refrigerant (R-12)......................... 1
Service Precautions........................ 2Service Valves........................... 3
System Charge........................... 5
System Discharge......................... 4
System Evacuation........................ 4
A/C OPERATION
The compressor increases the pressure and temper-
ature of the refrigerant. The heated refrigerant vapor
is then pumped into the condenser where it cools by
the air passing over the condenser fins. As the refrig-
erant cools in the condenser, it condenses into a liq-
uid. Still under high pressure, the liquid refrigerant
passes into the receiver. The receiver acts as a reser-
voir to furnish refrigerant to the expansion (H) valve
at all times. From the receiver, the high pressure liq-
uid refrigerant passes to the expansion (H) valve.
The expansion (H) valve meters refrigerant into the
evaporator where a low pressure is maintained by
the suction side of the compressor. As it enters the
evaporator, the refrigerant immediately begins to
boil by absorbing heat from the air passing over the
evaporator core. Having given up its heat to boil the
refrigerant, the air is cooled and passes into the pas-
senger compartment of the vehicle. From the evapo-
rator the vaporized refrigerant is drawn back to the
compressor to repeat the cycle.
REFRIGERANT (R-12)
It is illegal to release R-12 into the atmosphere.
SAFETY PRECAUTIONS
WARNING: EXTREME CARE MUST BE TAKEN TO
PREVENT ANY LIQUID REFRIGERANT FROM COM-
ING IN CONTACT WITH THE SKIN AND ESPE-
CIALLY THE EYES. ALWAYS WEAR SAFETYGOGGLES WHEN SERVICING ANY PART OF THE
REFRIGERANT SYSTEM. IF EYE CONTACT IS
MADE, APPLY A FEW DROPS OF MINERAL OIL TO
THE EYES AND FLUSH WITH WATER FOR SEV-
ERAL MINUTES. SEEK MEDICAL ATTENTION IMME-
DIATELY.
The refrigerant used in the air conditioner system
is Refrigerant-12 (R-12). R-12 is nonexplosive, non-
flammable, non-corrosive, has practically no odor and
is heavier than air. Although it is classified as a safe
refrigerant, certain precautions must be observed to
protect the parts involved and the person who is
working on the unit. Liquid R-12, at normal atmo-
sphere pressures and temperatures, evaporates so
quickly that it has the tendency to freeze anything it
contacts.
WARNING: TO AVOID A DANGEROUS EXPLOSION,
NEVER WELD OR STEAM CLEAN NEAR AIR CON-
DITIONING LINES OR COMPONENTS. DO NOT
HEAT R-12 ABOVE 52ÉC (125ÉF).
The R-12 in the system is always under pressure.
Because the system is tightly sealed, heat applied to
any part could cause this pressure to build up exces-
sively.
JHEATING AND AIR CONDITIONING 24 - 1

WARNING: LARGE AMOUNTS OF REFRIGERANT
RELEASED IN A CLOSED WORK AREA WILL DIS-
PLACE THE OXYGEN AND CAUSE SUFFOCATION.
ALWAYS MAINTAIN GOOD VENTILATION SUR-
ROUNDING THE WORK AREA.
R-12 gas, under normal conditions, is non-poison-
ous.
WARNING: THE DISCHARGE OF R-12 GAS NEAR
AN OPEN FLAME CAN PRODUCE A VERY POISON-
OUS GAS CALLED PHOSGENE. PHOSGENE IS
GENERATED WHEN A FLAME-TYPE LEAK DETEC-
TOR IS USED.
CAUTION: When charging an A/C system always
keep the tank in an upright position. If the tank is
on its side or upside down, liquid refrigerant will
enter the system and may damage the compressor.
In most instances when charging or adding refrig-
erant, moderate heat is required to bring the pres-
sure of the refrigerant above the pressure of the
system. A bucket or large pan of hot water, not over
52ÉC (125ÉF), is all the heat required for this pur-
pose. DO NOT heat the refrigerant container with a
blow torch or any other means that would raise the
temperature and pressure above this temperature.
CAUTION: DO NOT allow liquid refrigerant to touch
bright metal. Refrigerant will tarnish bright metal
and chrome surfaces. Refrigerant in combination
with moisture is very corrosive and can cause ex-
tensive damage to all metal surfaces.
Avoid splashing the refrigerant on any surface.
RECYCLING
(R-12) refrigerant is a chloroflorocarbon (CFC) that
can contribute to the depletion of the ozone layer in
the upper atmosphere. Ozone filters out harmful ra-
diation from the sun. To assist in protecting the
ozone layer, Chrysler Corporation requires that an
(R-12) refrigerant recovery device that meets SAE
standard J1991 be used. Contact an automotive ser-
vice equipment supplier for refrigerant recycling
equipment that is available in your area. Refer to
the operating instructions provided with the recy-
cling equipment for proper operation.
SERVICE PRECAUTIONS
Never open or loosen a connection before discharg-
ing the system refrigerant.
A system which has been opened to replace a com-
ponent or one which has discharged through leakage
must be evacuated before charging.
Immediately after disconnecting a component from
the system, seal the open fittings with a cap or plug.Before disconnecting a component from the system,
clean the outside of the fittings thoroughly.
DO NOT remove the sealing caps from a replace-
ment component until ready to install.
Refrigerant oil will absorb moisture from the atmo-
sphere if left uncapped. DO NOT open an oil con-
tainer until ready to use and install the cap
immediately after using. Store the oil only in a clean
moisture-free container.
Before connecting an open fitting always install a
new seal ring. Coat the fitting and seal with clean
refrigerant oil before connecting.
When installing a refrigerant line avoid sharp
bends. Position the line away from the exhaust or
any sharp edges which may chafe the line.
Tighten fittings only to the specified torque. The
copper and aluminum fittings used in the A/C system
will not tolerate over tightening.
When disconnecting a fitting use a wrench on both
halves of the fitting to prevent twisting of the refrig-
erant lines or tubes.
DO NOT open a refrigerant system or uncap a re-
placement component unless it is as close as possible
to room temperature. This will prevent condensation
from forming inside of a component which is cooler
than the surrounding air.
Keep service tools and the work area clean. Con-
tamination of A/C system through careless work hab-
its must be avoided.
PRESSURE GAUGE AND MANIFOLD ASSEMBLY
Pressure Gauge and Manifold Assembly Tool
C-3740-B (Fig. 1) is the most important tool used to
service the air conditioning system. The gauge as-
sembly is used to determine:
²System high side gauge pressures
²System low side gauge pressures
²The correct refrigerant charge
²System diagnosis
It is designed to provide simultaneous high and low
side pressure indications, because these pressures
must be compared to determine the correct system
operation.
LOW SIDE GAUGE
The low side gauge is a compound gauge, which
means that it will register both pressure and vacuum
(Fig. 1). The compound gauge is calibrated 0-1034
kPa (0-150 psi) pressure and 0-760 mm (0-30 in.) of
mercury vacuum. It is connected to the suction ser-
vice valve to check the low side pressure or vacuum.
HIGH SIDE GAUGE
The high side gauge is used to check the pressure
in the discharge side of the air conditioning system
(Fig. 1).
24 - 2 HEATING AND AIR CONDITIONINGJ

(2) Close all the hand valves.
(3) Connect the red charging hose to the discharge
service valve.
(4) Connect the blue charging hose to the inlet
(suction) service valve.
(5) Discharge the system. Leave the suction and
discharge service valves in the mid-position.
CAUTION: The system must be completely dis-
charged into a recovery device before evacuating. If
the system is still charged, refrigerant can enter
and damage the vacuum pump.
(6) Connect the vacuum pump hose to the vacuum
pump inlet.
(7) Open the low and high pressure control valves
on the charging station.
(8) Start the vacuum pump. Open the vacuum con-
trol valve and note the vacuum reading.
(9) Test the system for leaks as follows:
²Close the manifold hand valves.
²Stop the vacuum pump and observe the vacuum
reading.
²If the system is leak-free, vacuum will hold steady
at the level indicated when the pump was stopped. If
vacuum remains steady for 3-5 minutes, resume and
continue evacuation for a minimum of 30 minutes.
²If the system has a leak, vacuum will fall off or
rapidly drop to a 0 reading. If a leak exists, partially
charge the system. Find and repair the leak and re-
sume evacuation.
(10) Continue evacuating the system for a mini-
mum of 30 minutes after attaining the lowest vac-
uum level.
(11) Fill the station charging cylinder while the
system is evacuating.
(12) Close the vacuum control valve and stop the
vacuum pump.
(13) Observe low pressure gauge to determine if a
system leak exists. If the system is leak-free, the sys-
tem is now ready for charging.
SYSTEM CHARGE
CHARGE CAPACITY
The recommended system charge is 1.1 kg (38 oz.)
of R-12 refrigerant for XJ vehicles and 0.9 kg (32 oz.)
for YJ vehicles.
Add an additional 28 grams (1 fluid oz.) of
compressor oil to the system when a hose, re-
ceiver-drier, condenser, expansion valve or
evaporator core is replaced.
PORTABLE SERVICE STATION
(1) Fill the station charging cylinder. Refrigerant
should be observed rising in the cylinder sight glass.
(2) Slightly open the valve at the top of the cylin-
der when pressure in the charging cylinder and re-frigerant supply tank are equal. This relieves head
pressure allowing refrigerant to continue filling the
cylinder.
(3) Observe the pressure gauge at the top of the
cylinder. Rotate the plastic cover on the cylinder un-
til the pressure heading column corresponds with the
gauge pressure in-line with the sight glass.
FOR EXAMPLE:ÐThe pressure gauge at the top
of the cylinder indicates 483 kPa (70 psi). Locate the
column with the pressure heading of 483 (70) and ro-
tate the cover so the 483 (70) column aligns with the
sight glass.
(4) When refrigerant reaches the correct level in
the sight glass, close the right hand valve at cylinder
base and on the refrigerant drum.
(5) Close the valve at the top of the charging cyl-
inder.
(6) Check for bubbles in the refrigerant using the
cylinder sight glass. If bubbles appear in the refrig-
erant, tilt the charging station rearward momen-
tarily.
(7) Connect the heating element cord to the power
pack receptacle and turn the heater switch ON.
(8) Allow the refrigerant to warm for about 10
minutes while the vacuum pump is operating.
WARNING: WEAR GOGGLES TO PROTECT THE
EYES.
(9) Discharge and evacuate the system.
(10) Close the low pressure valve on the charging
station.
(11) Fully open the left hand refrigerant control
valve at the base of the cylinder and the high pres-
sure valve on the charging station.
(12) Charge the system.
(13) Close the refrigerant control valve and the
high pressure valve on the charging station.
CAUTION: DO NOT permit the liquid level to drop
below 0 on the cylinder sight glass.
(14) Close the manifold gauges after completion of
the charging operation and check the high and low
side pressures.
(15) Check system operation.
CAUTION: DO NOT check system pressures until
the high and low pressure valves on the charging
station are closed. The low pressure gauge could
be damaged if the valves are open.
(16) Close all the valves on the charging station
and close the refrigerant drum valve when all the op-
erations are completed.
(17) Back-seat the service valves by turning them
fully counterclockwise. Install the quick seal caps on
the valves afterward.
JHEATING AND AIR CONDITIONING 24 - 5

SERVICE DIAGNOSISÐMECHANICAL
GENERAL
The reason for a decrease in cooling or heating ef-
ficiency must be understood before attempting repair
or replacement of parts. Determined if the condition
is the air conditioner, the heating system, its compo-
nents or the in the air flow system.
The air conditioning system generally operates at
peak efficiency at normal highway speeds. However,
a slight reduction in A/C performance may be expe-
rienced in congested city driving conditions; espe-
cially when ambient temperatures are high.
When diagnosing a gradual decrease in A/C perfor-
mance, remember to check condition of the condenser
and radiator fins. Air flow blockage of either compo-
nent, caused by dirt, foreign material or insects, will
affect the air conditioning and engine cooling sys-
tems. Vehicles equipped with a protective screen, can
restrict air flow to the radiator and condenser.
During high outside operating temperatures, a
slight increase in engine coolant temperature will oc-
cur when the air conditioner is operating.
A/C PERFORMANCE TEST
The pressure developed on the high side and low
side of the compressor indicates whether the system
is operating properly.
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.
WARNING: WEAR SAFETY GOGGLES WHEN SER-
VICING THE REFRIGERATION SYSTEM
(1) Attach an engine tachometer and refrigerant
Pressure Gauge and Manifold Assembly Tool
C-4740-A.
(2) Close both hand valves on the gauge and man-
ifold assembly.
(3) Set both service hand valve stems to the mid-
position.
(4) Engine should be warmed up with doors, win-
dows and hood closed.
(5) Operate air conditioning system with the en-
gine running at 1,000 RPM. Set the controls for max-
imum A/C, temperature control on full cool and
blower switch on high.
(6) Insert a thermometer into center discharge air
outlet and observe the air temperature. The temper-
ature should be approximately 7ÉC (45ÉF) at 27ÉC
(80ÉF) ambient temperature after 5 minutes of oper-
ation.(7) Observe the high and low side pressures. The
evaporator suction pressure should be 207-241 kPag
(30-35 psig). The compressor discharge pressure
should be 1103-1633 kPag (160-235 psig). It should
be noted that high ambient temperature and humid-
ity conditions will cause higher pressures and tem-
perature conditions. If the clutch cycles, take
readings before clutch disengages.
(8) If pressures are abnormal, refer to the Pressure
and Performance Diagnosis Charts.
The following charts have been developed for quick
reference. If the step by step method used is not com-
pletely understood, refer to the correct section of the
Service Manual for more detailed information.
COMPRESSOR VALVE PLATEÐLEAK TESTS
This test can be preformed with the compressor in-
stalled in the vehicle.
Discharge or Suction Valve BreakageÐWhen
compressor is operating at idle speed, compressor
makes a ``clacking'' sound. Preform the Pressure Bal-
ancing Test.
Head Gasket BreakageÐAt idle speed, discharge
pressure does not increase to normal condition and
suction pressure is high. Preform the Pressure Bal-
ancing Test.
Pressure Balancing Test:
(1) Connect manifold gauge set to suction and dis-
charge ports.
(2) Run compressor for 5 minutes at idle speed and
stop.
(3) Measure elapsed time that discharge pressure
is balanced to suction pressure. If less than 2 min-
utes, it is determined that discharge valve or head
gasket is broken.
REFRIGERANT LEAK TEST
External leaks in the system can be located using
an electronic detector.
The electronic leak detector is recommended be-
cause it is light, accurate and most important, does
not expose the user to toxic gas fumes. An electronic
leak detector will locate R-12 leaks as small as 15 ml
(0.5 fluid oz.) per year.
WARNING: DO NOT USE A HALIDE TORCH. THE
HALIDE TORCH REQUIRES AN OPEN FLAME FOR
LEAK DETECTION. WHEN R-12 IS EXPOSED TO AN
OPEN FLAME, IT TURNS INTO PHOSGENE GAS
WHICH IS POISONOUS.
(1) Calibrate the detector as outlined in the manu-
facturer's instructions.
(2) Remove the flexible detector probe from the
case.
(3) Turn the detector control switch ON.
24 - 8 HEATING AND AIR CONDITIONINGJ

COMPRESSOR OVERHAUL
INDEX
page page
Compressor............................. 17
Compressor Isolation...................... 17
Description............................. 17Magnetic Clutch......................... 18
Purging Compressor of Air................. 17
DESCRIPTION
The A/C system uses a Sanden compressor. This
compressor is a 7 piston design. Designated the SD-
709, the compressor is mounted on the front right
side of the engine and is driven by a serpentine belt.
System lubrication is provided by 135cc615cc (4.6
cu. in.60.5 cu. in.) of 500 viscosity refrigerant oil.
The clutch used on the compressor consists of 3 ba-
sic components: the pulley, front plate and the field
coil. The pulley and field coil are attached to the
front head of the compressor with tapered snap rings.
The hub is keyed to the compressor shaft and is re-
tained on the shaft with a self-locking nut. Special
service tools are required to remove and install the
clutch plate on the compressor shaft.
COMPRESSOR ISOLATION
It is not necessary to discharge the system for com-
pressor removal. The compressor can be isolated from
the remainder of the system and eliminate the need
for recharging when performing compressor service.
(1) Connect pressure gauge and manifold.
(2) Close both gauge hand valves.
(3) Mid-position both service valves.
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.
(4) Start the engine and operate the air condition-
ing system.
(5) Turn the suction service valve slowly clockwise
toward the front seated position.
(6) When pressure drops to zero, stop the engine
and compressor and quickly finish front-seating the
suction service valve.
(7) Front-seat the discharge service valve.
(8) Loosen the oil level check plug slowly to re-
lease any internal pressure in the compressor.
The compressor is now isolated from the remainder
of the system.
The service valves can be removed from the com-
pressor.
PURGING COMPRESSOR OF AIR
The compressor must be purged of air whenever it
has been isolated for an oil level check or other ser-
vice procedures without discharging the entire sys-
tem.
(1) Cap the service gauge ports on both of the ser-
vice valves.
(2) Back-seat the suction service valve to allow the
system refrigerant to enter the compressor.
(3) Place the discharge service valve in the mid-po-
sition or cracked-position.
(4) Loosen the discharge service valve gauge port
cap to permit the refrigerant to force any air out of
the compressor.
(5) Back-seat the discharge service valve and
tighten the gauge port cap.
(6) The compressor is now ready for service.
COMPRESSOR
REMOVAL
(1) Isolate the compressor.
(2) Disconnect negative cable from battery.
(3) Disconnect the clutch lead wire.
(4) Remove the discharge and inlet (suction) ser-
vice valves from the compressor. Plug or tape all the
openings.
(5) Remove the serpentine drive belt (refer to
Group 7, Cooling System for the proper procedure).
(6) Remove the bolts and lift the compressor from
the mounting bracket (Figs. 1 and 2).
INSTALLATION
If a replacement compressor is being installed;
check the oil level. Add or subtract oil as neces-
sary and install the magnetic clutch on the com-
pressor.
(1) If the mounting bracket was removed, install
the bracket to the block. Tighten the mounting bolts
to 27 NIm (20 ft. lbs.) torque.
(2) Install the compressor on the mounting
bracket. Tighten the bolts to 27 NIm (20 ft. lbs.)
torque.
(3) Install the serpentine drive belt (refer to Group
7, Cooling System for the proper procedure).
(4) Tighten the serpentine drive belt to the speci-
fied tension.
²New belt tensionÐ800-900 N (180-200 lb-f).
JHEATING AND AIR CONDITIONING 24 - 17