1995 ISUZU TROOPER Workshop Manual

AIR CONDITIONING 1 B -19
ON-VEHICLE SERVICE
GENERAL REPAIR PROCEDURE
Precautions for Replacement or Repair of Air
Conditioning Parts
There are certain procedures, practices and pre­
cautions
that should be followed when servicing air
conditioning systems:
• Keep your work area clean.
•
Always wear safety goggle and protective gloves
when working on refrigerant systems.
• Beware of the danger of carbon monoxide fumes
caused by running the engine.
• Beware of discharged refrigerant in enclosed or
improperly ventilated garages.
• Always disconnect the negative battery cable and
discharge and recover the refrigerant
whenever
repairing the air conditioning system.
• When discharging and recovering the refrigerant,
do not allow refrigerant to discharge too fast; it
will draw compressor oil out of the system.
• Keep moisture and contaminants out of the sys­
tem.
When disconnecting or removing any lines
or parts, use plugs or caps to close the fittings
immediately.
Never remove the caps or plugs until the lines or
parts are reconnected or installed.
•
When disconnecting or reconnecting the lines,
use
two wrenches to support the line fitting, to
prevent from twisting or other damage.
• Always install new 0-rings whenever a connec­
tion is disassembled.
• Before connecting any hoses or lines, apply new
specified compressor oil to the 0-rings.
• When removing and replacing any parts which
require discharging the refrigerant circuit, the
operations described in
this section must be per­
formed in the following sequence:
1. Use the J-39500 (ACR4
: HFC-134a Refrigerant
Recovery/Recycling/Recharging/System)
or
equivalent to thoroughly discharge and re­
cover
the refrigerant.
2. Remove and replace the defective part.
3.
After evacuation, charge the air conditioning
system and check for leaks.
Repair of Refrigerant Leaks
Refrigerant Line Connections
Install new 0-rings, if required. When disconnecting
or connecting lines, use two wrenches to prevent the
connecting
portion from twisting or becoming
damaged. (Fig. 1 B-15) Fig.
18-15
When connecting the refrigerant
line at the block
joint, securely insert the projecting portion of the
joint portion into the connecting hole on the unit side
and secure
with a bolt.
Apply specified compressor oil to the 0-rings prior
to connecting. (Fig. 18-16)
CAUTION:
Compressor (PAGI oil to be used varies according
to compressor model. Be sure to apply oil specified
for the model of compressor.
~1;1_ ~ ' .. J '--......
Fig. 18-16
0-rings must be closely aligned with raised portion
of refrigerant line. (Fig. 18-17)
Insert nut into union. First tighten nut by hand as
much as possible. Then, tighten nut to specified
torque. (Fig. 1 8-18)

1 B -20 AIR CONDITIONING
OK NG NG
0 X X
ffB-mEt
0-ring
Raised portion
Fig. 18-17
0
Fig. 18-18
Leak at Refrigerant Line Connections
1. Check the torque on the refrigerant line fitting
and, if too loose, tighten to the specified torque.
• Use two wrenches to prevent twisting and
damage to the line.
•
Do not over tighten.
2. Perform a leak test on the refrigerant line fitting.
3. If the leak is still present, discharge and recover
the refrigerant from the system.
4. Replace the 0-rings.
• 0-rings cannot be reused. Always replace
with new ones.
• Be sure to apply specified compressor oil to
the new 0-rings.
5. Retighten the refrigerant line fitting to the spe­
cified torque.
• Use two wrenches to prevent twisting and
damage to the line.
6. Evacuate, charge and retest the system.
Leaks in the Hose
If the compressor inlet or outlet hose is leaking, the
entire hose must be replaced. Refrigerant hose must
not be cut or spliced for repair.
1.
2.
3.
4.
5.
Locate the leak.
Discharge and recover the refrigerant.
Remove
the hose assembly.
• Cap the open connections at once.
Connect
the new hose assembly.
•
Use two wrenches to prevent twisting or
damage to the hose fitting.
• Tighten the hose fitting to the specified
torque.
Evacuate, charge and test the system.
Compressor Leaks
If leaks are located around the compressor shaft seal
or shell, replace or repair the compressor.
Recovery, Recycling, Evacuation and Charging
Handling HFC-134a:
Air conditioning systems contain HFC-134a.
This is a chemical mixture which requires special
handling procedures to avoid personal injury.
• Always wear safety goggles and protective
gloves.
•
Always work in a well-ventilated area. Do not
weld or steam clean on or near any vehicle­
installed air conditioning lines or components.
• If HFC-134a should come in contact with any part
of the body, flush the exposed area with cold
water and immediately seek medical help.
•
If it is necessary to transport or carry any
container of HFC-134a in a vehicle, do not carry it
in the passenger compartment.
• If it is necessary to fill a small HFC-134a container
from a large one, never fill the container com­
pletely. Space should always be allowed above
the liquid for expansion.
• HFC-134a and R-12 should never be mixed as their
compositions are not the same.
• HFC-134a PAG oil tends to absorb moisture more
quickly than R-12 mineral oil and, therefore,
should be handled more carefully.
•
Keep HFC-134a containers stored below 40°C
(100°F).
WARNING: • SHOULD
HFC-134a CONTACT YOUR EYE(S),
CONSULT
A DOCTOR IMMEDIATELY.
•
DO NOT RUB THE AFFECTED EYE(S). INSTEAD,
SPLASH QUANTITIES
OF FRESH COLD WATER
OVER THE AFFECTED AREA TO GRADUALLY
RAISE THE TEMPERATURE OF THE RE­
FRIGERANT ABOVE THE FREEZING POINT.
• OBTAIN
PROPER MEDICAL TREATMENT AS
SOON
AS POSSIBLE. SHOULD THE HFC-134a
TOUCH THE SKIN, THE INJURY MUST BE
TREATED THE SAME AS SKIN WHICH HAS BEEN
FROSTBITTEN OR FROZEN.

Refrigerant Recovery
The refrigerant must be discharged and recovered by
using the J-39500 (ACR4
: HFC-134a Refrigerant Re­
covery/Recycling/Recharging/System) or equivalent
before removing or mounting air conditioning parts.
1. Connect the high and low charging hoses of the
ACR4 (or equivalent) as shown below. (Fig.
18-19)
J-39500
(High side)
Fig. 18-19
2. Recover the refrigerant by following the Manu­
facturer's Instructions.
3. When a part is removed, put a cap or a plug on
the connecting portion so that dust, dirt or
moisture cannot get into it.
Refrigerant Recycling
Recycle the refrigerant recovered by J-39500
(ACR4: HFC-134a Refrigerant Recovery/Recycling/Re­
charging/System) or equivalent.
For the details of the actual operation, follow the
steps in the ACR4 (or equivalent) Manufacturer's In­
structions.
Evacuation of the Refrigerant System
(Fig. 1 B-20)
NOTE:
Explained below is a method using a vacuum
pump. Refer to the ACR4 (or equivalent) manufac­
turer's instructions when evacuating the system
with a ACR4 (or equivalent).
Air and moisture in the refrigerant will cause prob­
lems in the air conditioning system.
Therefore,
before charging the refrigerant, be sure to
evacuate air and moisture thoroughly from the
system.
AIR CONDITIONING 1 B -21
Fig. 18-20
1. Connect the gauge manifold.
• High-pressure valve (HI)-Discharge-side
• Low-pressure valve (LOW)-Suction-side
2. Discharge and recover the refrigerant.
3. Connect the center hose of the gauge manifold
set to the vacuum pump inlet.
4. Operate the vacuum pump, open shutoff valve
and then open both hand valves.
5. When the low-pressure gauge indicates ap­
prox. 750 mmHg (30 inHg), continue the evacu­
ation for 5 minutes or more.
6. Close both hand valves and stop the vacuum
pump.
7. Check to ensure that the pressure does not
change after 10 minutes or more.
• If the pressure changes, check the system for
leaks.
• If leaks
occur, retighten the refrigerant line
connections and repeat the evacuation steps.
8. If no leaks are found, again operate the vacuum
pump for 20 minutes or more. After confirming
that the gauge manifold pressure is at 750
mmHg (30 inHg), close both hand valves;
9. Close positive shutoff valve.
Stop the vacuum pump and disconnect the
center hose from the vacuum pump.