SUBARU LEGACY 1995 Service Repair Manual

2. Basic Information
1) The combination of moisture and refrigerant forms acid,
therefore, moisture should not be allowed to enter the
refrigerant.
2) Refrigerant oil readily absorbs moisture, therefore, keep
refrigerant oil containers tightly capped.
3) The process of evacuating the system is performed to
remove small amounts of moisture. This is accomplished
by lowering the pressure inside the system, which allows
the moisture to boil off, in much the same way that a pot
of water will boil away to nothing given enough time. The
evacuation process does not suck the moisture out of the
system.
4) A minimum level of vacuum must be reached to satis-
factorily evacuate the system. This minimum level of
vacuum depends on the temperature inside the system.
The chart below shows the level of vacuum required to boil
water at various temperatures.
Additionally, the vacuum level shown on a gauge will read
approx. 4 kPa (25 mmHg, 1 inHg) less for each 304.8 m
(1,000 ft) above sea level, due to the decrease in atmo-
spheric pressure at altitude.
Vacuum level required to boil water (at sea level)
Temperature°C(°F) Vacuum kPa (mmHg, inHg)
1.7 (35) 100.9 (757, 29.8)
7.2 (45) 100.6 (754, 29.7)
12.8 (55) 99.9 (749, 29.5)
18.3 (65) 99.2 (744, 29.3)
23.9 (75) 98.5 (739, 29.1)
29.4 (85) 97.2 (729, 28.7)
35 (95) 95.8 (719, 28.3)
11
4-7SERVICE PROCEDURE
2. Basic Information

3. Tools and Equipment
The following section provides information about the tools
and equipment that will be necessary to properly service
the A/C system.
Since equipment may vary slightly depending on the
manufacturer, it is important to always read and follow the
manufacturer’s instructions.
CAUTION:
When working on vehicles with the HFC-134a system,
only use HFC-134a specified tools and parts. Do not
mix with CFC-12 tools and parts. If HFC-134a and
CFC-12 refrigerant or compressor oil is mixed, poor
lubrication will result and the compressor itself may be
destroyed.
In order to help prevent mixing HFC-134a and CFC-12
parts and liquid, the tool and screw type and the type
of service valves used are different. The gas leak
detectors for the HFC-134a and CFC-12 systems must
also not be interchanged.
HFC-134a CFC-12
Tool & screw type Millimeter size Inch size
Valve type Quick joint type Screw-in type
Tools and Equipment Description
WRENCH
VariousWRENCHESwill be required to service any A/C
system. A 7 to 40 N⋅m (0.7 to 4.1 kg-m, 5 to 30 ft-lb) torque
wrench with various crowfoot wrenches will be needed. Open
end or flare nut wrenches will be needed for back-up on the
tube and hose fittings.
G4M0571
APPLICATOR BOTTLE
A smallAPPLICATOR BOTTLEis recommended to apply
refrigerant oil to the various parts. They can be obtained at a
hardware or drug store.
G4M0572
12
4-7SERVICE PROCEDURE
3. Tools and Equipment

Tools and Equipment Description
MANIFOLD GAUGE SET
AMANIFOLD GAUGE SET(with hoses) can be obtained
from either a commercial refrigeration supply house or from
an auto shop equipment supplier.
G4M0573
REFRIGERANT RECOVERY SYSTEM
AREFRIGERANT RECOVERY SYSTEMis used for the
recovery and reuse of A/C system refrigerant after
contaminants and moisture have been removed from the
refrigerant.
G4M0574
SYRINGE
A graduated plasticSYRINGEwill be needed to add oil back
into the system. The syringe can be found at a pharmacy or
drug store.
G4M0575
VACUUM PUMP
AVACUUM PUMP(in good working condition) is necessary,
and may be obtained from either a commercial refrigeration
supply house or an automotive equipment supplier.
G4M0576
CAN TAP
ACAN TAPfor the 397 g (14 oz) can is available from an
auto supply store.
G4M0577
13
4-7SERVICE PROCEDURE
3. Tools and Equipment

Tools and Equipment Description
THERMOMETER
PocketTHERMOMETERSare available from either industrial
hardware store or commercial refrigeration supply houses.
G4M0578
ELECTRONIC LEAK DETECTOR
AnELECTRONIC LEAK DETECTORcan be obtained from
either a specialty tool supply or an A/C equipment supplier.
G4M0579
WEIGHT SCALE
AWEIGHT SCALEsuch as an electronic charging scale or a
bathroom scale with digital display will be needed if a 13.6 kg
(30 lb) refrigerant container is used.
G4M0580
14
4-7SERVICE PROCEDURE
3. Tools and Equipment

4. O-ring Connections
1. GENERAL
The following points should be kept in mind when assem-
bling O-ring connections.
1) Avoid unnecessary handling and contact of O-rings with
your hands, since even clean fingers contain body acids,
which can contaminate the O-ring surface.
2) Do not handle O-rings with gloves, shop towels, etc.,
since lint particles may cling to the O-ring, possibly caus-
ing a leak upon assembly.
3) Always lubricate O-rings before assembly to allow the
O-ring to seat itself properly.
4) Be certain to use torque wrenches when tightening
O-ring fittings, because overtightening can not only dam-
age the O-ring, but it can distort the tube end as well.
G4M0581
2. REMOVE PROTECTIVE SEALS
Just prior to making the connection, remove the protective
seals.
CAUTION:
If for any reason you have to stop before making a
connection, recap the tube, component or fitting.
G4M0582
Visually inspect the O-ring surface, the O-ring mating
surface, the threads and the connection points. If a defec-
tive part is found, replace it.
The O-ring must sit square against the tube bead. If
necessary, slide the O-ring into proper positionwith clean
hands.
15
4-7SERVICE PROCEDURE
4. O-ring Connections

G4M0583
3. LUBRICATE THE COMPONENTS
For lubrication of the components, use only refrigerant oil
as described in the appropriate service manual. Apply oil
from an oil squirt gun or other closed container. Do not use
your finger to spread the oil over the O-ring.
Apply a small amount of refrigerant oil to the top and sides
of the O-ring. The area covered by oil should include the
O-ring and the tube bead.
G4M0584
4. TORQUE THE FITTING
Using a back-up wrench in conjunction with a calibrated
torque wrench, torque the connection to the midrange of
the specification.
After completion of torquing, use a clean shop towel to
remove any excess oil from the connection or any oil that
may have dripped on the vehicle body or other parts.
CAUTION:
If a leak is suspected after torquing, do not retighten
or retorque the connection. Instead, disassemble the
connection, remove the O-ring, and inspect the O-ring,
threads, joints and seating surfaces.
16
4-7SERVICE PROCEDURE
4. O-ring Connections

5. Refrigerant Service Procedure
1. WORK FLOW
17
4-7SERVICE PROCEDURE
5. Refrigerant Service Procedure

6. Discharge the System
CAUTION:
The following points should be kept in mind when dis-
charging the system.
Be certain that goggles and gloves are worn.
Connect refrigerant recovery system to manifold
gauge set and remove recycle refrigerant from A/C
system.
NOTE:
Refer to appropriate refrigerant recovery system instruction
manual for operation.
G4M0585
1. CONNECTING THE MANIFOLD GAUGE SET
1) Close the high and low side manifold valves.
G4M0586
2) Turn the A/C system ON and turn the IG switch OFF.
3) Attach the high- and low-pressure manifolds to the high
and low services port on the vehicle.
2. PREPARE FOR DISCHARGING
Connect the center manifold hose to the refrigerant recov-
ery system to recycle refrigerant.
18
4-7SERVICE PROCEDURE
6. Discharge the System

G4M0596
7. Evacuating and Charging
The following points should be kept in mind when evacu-
ating and charging with a manifold gauge set.
1) Be certain that goggles and gloves are worn.
2) If bulk refrigerant [13.6 kg (30 lb) canister] is used, be
certain to weigh the charge amount carefully, using the
correct equipment, to avoid overcharging the system.
3) The charging procedure described in this section
begins by chargingliquidrefrigerant into the high- pres-
sure side of the systemwith the engine off.The proce-
dure is completed by charging refrigerantvaporinto the
low-pressure side of the system with the engine running.
CAUTION:
Never open the high-pressure manifold valve when the
engine is running.
G4M0597
1. CONNECT THE GAUGE SET
1) Close the high- and low-pressure manifold valves.
2) Attach the low-pressure manifold hose to the low- pres-
sure service port on the vehicle. Check the low- pressure
gauge. If more than 68.6 kPa (0.70 kg/cm
2, 10 psi) is
indicated, discharge the system prior to charging.
3) Attach the high-pressure manifold hose to the high-
pressure service port on the vehicle.
4) Connect the center hose from the manifold to the
vacuum pump.
5) Turn on the vacuum pump.
6) Slowly open the low-pressure manifold valve.
7) When the low-pressure gauge reaches approximately
66.43 kPa (498.3 mmHg, 19.62 inHg), slowly open the
high-pressure manifold valve.
G4M0598
8) Maintain a minimum vacuum level of 100.56 kPa (754.4
mmHg, 29.70 inHg) for a minimum of 15 minutes on a new
system or 30 minutes for an in-service system.
NOTE:
The gauge will read 4 kPa (25 mmHg, 1 inHg) less for
every 304.8 m (1,000 ft) above sea level.
19
4-7SERVICE PROCEDURE
7. Evacuating and Charging

G4M0599
2. PERFORM A VACUUM LEAK TEST
1) After 15 minutes (or more) of evacuation, close the
high-pressure manifold valve.
2) Close the low-pressure manifold valve.
3) Turn off the vacuum pump.
G4M0600
4) Note the low side gauge reading.
5) After 5 minutes, re-check the low-pressure gauge read-
ing.
If the vacuum level has changed more than 4 kPa (25
mmHg, 1 inHg), perform an HFC-134a leak test.
If the vacuum reading is about the same as noted in step
2-4), continue on to step 2-6).
G4M0980
6) Carefully attach the can tap to the refrigerant can by
following the can tap manufacturer’s instructions.
7) Disconnect the center manifold hose from the vacuum
pump and connect the hose to the tap valve.
G4M0981
8) If a 13.6 kg (30 lb) container of refrigerant is used a
weight scale will be needed. This scale is to determine the
amount of refrigerant that is used.
Connect the center hose from the manifold to the valve.
Place the 13.6 kg (30 lb) container on the scale, valve end
down.
G4M0603
3. PURGE THE CENTER HOSE
1) Verify that all three hose connections are tight at the
manifold gauge set.
2) Open the valve on the HFC-134a source.
3)With safety equipment in place (goggles and
gloves), use extreme cautionand loosen the center hose
connection at the manifold and allow the HFC-134a to
escape for no more than two or three seconds, then quickly
retighten the hose fitting at the manifold.
20
4-7SERVICE PROCEDURE
7. Evacuating and Charging