turn CHEVROLET CAMARO 1967 1.G Chassis User Guide

HEATER AND AIR CONDITIONING 1A-28

providing a protective film to reduce the possibility

of infection.

3.
As soon as possible, call or consult an eye specialist

for immediate and future treatment.

REMEMBER -

pound of cure."
"An ounce of prevention is worth a

PRECAUTIONS IN HANDLING REFRIGERANT LINES

• All metal tubing lines should be free of kinks, be-

cause of the restriction that kinks will offer to the

flow of refrigerant. The refrigeration capacity of the

entire system can be greatly reduced by a single

kink.

• The flexible hose lines should never be bent to a

radius of less than 10 times the diameter of the hose.

• The flexible hose lines should never be allowed to

come within a distance of 2-1/2" of the exhaust

manifold.

• Flexible hose lines should be inspected at least once

a year for leaks or brittleness. If found brittle or

leaking they should be replaced with new lines.

• Use only sealed lines from parts stock.

• When disconnecting any fitting in the refrigeration

system, the system must first be discharged of all

refrigerant. However, proceed very cautiously re-

gardless of gauge readings. Open very slowly, keep-

ing face and hands away so that no injury can occur

if there happens to be liquid refrigerant in the line.

If pressure is noticed when fitting is loosened, allow

it to bleed off very slowly.

CAUTION: Always wear safety goggles when

opening refrigerant lines.

• In the event any line is opened to atmosphere, it

should be immediately capped to prevent entrance

of moisture and dirt.

• The use of the proper wrenches when making con-

nections on "O" ring fittings is important. The use

of improper wrenches may damage the connection.

The opposing fitting should always be backed up with

a wrench to prevent distortion of connecting lines or

components. When connecting the flexible hose con-

nections it is important that the swagged fitting and

the flare nut, as well as the coupling to which it is

attached, be held at the same time using three dif-

ferent wrenches to prevent turning the fitting and

damaging the ground seat.

• "O" rings and seats must be in perfect condition.

The slightest burr or piece of dirt may cause a leak.

• Sealing beads on hose clamp connections must be

free of nicks and scratches to assure a perfect seal.

MAINTAINING CHEMICAL STABILITY IN THE

REFRIGERATION SYSTEM

The metal internal parts of the Chevrolet refrigeration

system and the refrigerant and oil contained in the sys-

tem are designed to remain in a state of chemical

stability as long as pure R-12 and uncontaminated re-

frigeration oil is used in the system.

However, when abnormal amounts of foreign materials,

such as dirt, air or moisture are allowed to enter the

system, the chemical stability may be upset. When ac-

celerated by heat, these contaminates may form acids
Fig.
40-^-System Contaminants

and sludge and eventually cause the breakdown of com-

ponents within, the system. In addition, contaminates may

affect the temperature-pressure relationship of R-12,

resulting in improper operating temperature and pres-

sures and decreased efficiency of the system.

The following general practices should be observed to

insure chemical stability in the system.

• Whenever it becomes necessary to disconnect a

refrigerant or gauge line, it should be immediately

capped. Capping the tubing will also prevent dirt and

foreign matter from entering.

• Tools should be kept clean and dry. This also in-

cludes the gauge set and replacement parts.

• When adding oil, the container should be exception-

ally clean and dry due to the fact that the refrigera-

tion oil in the container is as moisture-free as it is

possible to make it. Therefore, it will quickly absorb

any moisture with which it comes in contact. For

. this same reason the oil container should not be

opened until ready for use and then it should be

capped immediately after use.

• When it is necessary to open a system, have every-

thing you will need ready and handy so that as little

Fig.
41—Gauge Set

CHEVROLET CHASSIS SERVICE MANUAL

HEATER
AND AIR
CONDITIONING
1A-31

FIVE
AMP

TIME DELAY

FUSE

CORD
TO

110
AC
SOURCE
PUMP

INLET
PUMP DISCHARGE

OUTLET

Fig.
44—Vacuum Pump

the use of weighing equipment necessary with the larger

drum. The single can Valve J-6271 can be used for com-

pleting the charge and for miscellaneous operations such
Fig.
45-R-12 Disposable Cans

as flushing. The valves are installed by piercing the top

seal of the cans.

Evacuating and charging procedures later in this sec-

tion will make use of the J-8393 Charging Station which

uses the 25 lb. drum of refrigerant.

COMPRESSOR OIL

Special refrigeration lubricant should be used in the

system. It is available in 1 quart graduated bottles

through Parts Stock. This oil is as free from moisture

and contaminants as it is possible to attain by commercial

processes. This condition should be preserved by im-

mediately capping the bottle when not in use.

See "Air Conditioning System Capacities" for the

total system oil capacity.

Due to the porosity of the refrigerant hoses and con-

nections, the system refrigerant level will show a definite

drop after a period of time. Since the compressor oil is

carried throughout the entire system mixed with the

refrigerant a low refrigerant level will cause a dangerous

lack of lubrication. Therefore the refrigerant charge in

the system has a definite tie-in with the amount of oil

found in the compressor and an insufficient charge may

eventually lead to an oil build-up in the evaporator.

COMPRESSOR SERIAL NUMBER

The compressor serial number is located on the serial

number plate on top of the compressor. The serial num-

ber consists of a series of numbers and letters. This

serial number should be referenced on all forms and

correspondence related to the servicing of this part.

INSPECTION AND PERIODIC SERVICE

PRE-DELIVERY INSPECTION

1.
Check that engine exhaust is suitably ventilated.

2.
Check the belt for proper tension.

3.
With controls positioned for operation of the system,

operate the unit for ten minutes at approximately

2000 rpm. Observe the clutch pulley bolt to see that

compressor is operating at the same speed as the
clutch pulley. Any speed variation indicates clutch

slippage.

Before turning off the engine, check the sight glass

to see that the.unit has a sufficient Refrigerant

charge. The glass should be clear, although during

milder weather it may show traces of bubbles. Foam

in.
the flow indicates a low charge. No liquid visible

indicates no charge.

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-33

within the system. The following fixed conditions must be

adhered to in order to make it possible to compare the

performance of the system being tested with the stan-

dards below:

1.
Doors and windows closed. (Car inside or in shade.)

2.
Hood up and engine exhaust suitably ventilated.

3.
Vehicle in NEUTRAL with engine running at 2000

rpm.

4.
Air Conditioning controls set for -

• Maximum cooling.

• High blower speed.

5.
TEMP knob and AIR knob set for full recirculating

air. On Comfortron systems* move the control lever

to REAR and pull the white vacuum hose from the

transducer. Plug the hose. An alternate method is to

install the J-22368 Tester (described later in this

section) and operate it on MANUAL control to main-

tain maximum cooling and blower speed.

6. Gauge set installed.

7.
System settled out (run-in approximately
10
minutes).

8. A thermometer placed in front of vehicle grille and

another in the right hand diffuser outlet.

PERFORMANCE DATA

The following Performance Data define normal opera-

tion of the system under the above conditions. Relative

humidity does not appear in the tables because after

running the prescribed length of time on recirculated air

and maximum cooling, the relative humidity of the air

passing over the evaporator core will remain at ap-

proximately 35% to 40% regardless of the ambient

temperature or humidity.

Should excessive head pressures be encountered at

higher ambient temperatures, an 18" fan placed in front

of the vehicle and blowing into the condenser will provide

the extra circulation of air needed to bring the pressures

to within the limits specified.

NOTE: Higher temperatures and pressures will

occur at higher ambient temperatures, fti areas

of high humidity it is possible to have ther-

mometer and gauge readings approach but not

reach the figures listed in the performance

tables and still have a satisfactory operating

unit. However, it is important to remember that

low pressure has a direct relationship to nozzle

outlet temperature. If pressure is too low, ice

will gradually form on the evaporator fins, re-

stricting airflow into the passenger area and

resulting in insufficient or no cooling.

Four-Season and Comfortron System

Chevrolet and Camaro
Chevelle

(Refrigerant
Charge
=

Temperature
of Air

Entering Condenser

Engine rpm

Compressor

Head Pressure

Evaporator Pressure

at POA

Discharge Air Temp,

at Right Hand Outlet
3
Lbs. -

70°

145-

155

38-

41
80°

170-

180
12 02

90°
.)

100°

2000

205-

215

29.5 -

39-

42
41-

43
255-

265

30.5

42-

45
110°

260-

270

psi

43-

46
120°

295-

305

45-

48
(Refrigerant Charge =

Temperature of

Air Entering

Condenser

Engine rpm

Compressor Head

Pressure

Evaporator
Pressure

at
POA

Discharge Air

Temp, at Right

Hand Outlet
3 Lbs. -

70°

150

160

37-

40
80°

175

185
12 Oz.)

90° 100°

2000

210 250

220 260

29.5 - 30.5

37-

40
38-
39-

41 42
110°

280

290

psi

40-

44
120°

290

300

41-

45

Corvette

(Refrigerant Charge =

Temp, of Air

Entering Condenser

Engine rpm

Compressor

Head Pressure

Evaporator
Pressure

at
POA

Outlet
Air

Temperature

(at Right
Outlet)
3
Lbs.

70°

150-

170

38-

40
- 4 Oz.)

80°

175-

195

29

38-

40
90°

2000

200-

200
100°

i*pm

240-

260
110°

285-

300

5-
30.5 psi

40-

42
41-

43
43-

45
120°

325-

335

45-

47

Alt Weather System

Chevy II

(Refrigerant
Charge
=

Grille Air

Temperature

Engine rpm

Compressor Head

Pressure

Compressor Suction

Pressure**

Discharge Air Temp,

at R/H Outlet**
2-1/2 Lbs.)

70°

120-

140

13

32-

37
80°

150-

160

14
CO
OO
CO
CO
90°
100°

1500

175-

185

15

35-

40
220-

230

15

36-

41
110°

240-

250

19

37-

42
120°

265-

275

19

38-

43

**When Compressor Clutch Releases

COMFORTRON SYSTEM OPERATIONAL TEST

This test, designed as a quick check of total system

operation, must be made with the engine operating at

minimum of 2000 rpm and coolant warm. Wait several

seconds between operations to allow the system to move

through its sequence of operation and arrive at the pre-

scribed mode of operation.

1.
With control lever in the OFF position, and Tem-

perature Dial at 65°F.

a. System is turned OFF, there is no air flow from

any of outlets.

2.
Control lever in HI Front and Temperature Dial set

at65°F.

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-40

THERAAAL VACUUM

VALVE
TO ENGINE

VACUUM

SOURCE

VACUUM STORAGE

TANK

OUTSIDE AIR

DIAPHRAGM

MODE

DIAPHRAGM

VACUUM

RELAY
BLACK

DEFOG-DEICE

DIAPHRAGM

GREEN

BLACKj ||
|
BROWN

CONTROL

VALVE

Fig.
50—Comfortron Vacuum Diagram

are fused which will lead to evaporator freeze-up.

Replace the switch.

• If the compressor does not operate regardless of

the position of the knob a loss of the power

element charge is indicated provided that it has

been established that power is supplied to the

switch. This, of course, results in no cooling.

Replace the switch.

• Check the screw threads for stripped or other-

wise damaged threads.

Adjusting Switch

H, after checks above, the switch seems to be operating

properly,

follows:
adjust for proper setting if necessary, as
1.
(Chevy II All-Weather) Turn the outer air deflector

in the face plate so that the attaching screws may

be removed; Then remove the control knobs, bezels

and the thermostatic switch. (Universal) remove the

face plate retaining screws. Pull the faceplate away

from the case when ready to turn the switch adjusting

screw.

2.
Vehicle must be set up as in Step 2 above.

3.
The suction side of the system, read on the low

pressure gauge, should pull down to the pressure

shown in the chart in Performance Test under the

ambient temperature at the time the switch is being

set.

4.
If the low side pulls down lower than the prescribed

pressure at the end of each cooling cycle, turn the

adjusting screw (See Figure 54) clockwise in single

CHEVROLET CHASSIS SERVICE MANUAL

HEATER
AND AIR
CONDITIONING
1A-41

OUTLET

1

TO EXPANSION
^

VALVE
TO
OIL

BLEED LINE

^ INLET

Fig.
51—Evaporator Pressure Control Valve—POA

turn increments until
the
suction pressure rises
to

the correct pressure.

5.
If the
pressure
is
more than
it
should
be,
turn the

adjusting screw counter-clockwise until
the
proper

pressure
is
reached.

6. After adjusting
the
switch, install the capillary to
its

normal position
and
observe
the
operation
of the

system
for
several minutes. Then
if
the operation
is

satisfactory remove the gauge
set,
replace the switch

and reinstall the face plate onto the evaporator case.

EXPANSION VALVE

A malfunction
of the
expansion valve will
be
caused

by
one of the
following conditions: valve stuck open,

valve stuck closed, broken power element,
a
restricted

screen
or an
improperly located
or
installed power

element bulb.
The
first three conditions require valve

replacement.
The
last two may be corrected by replacing

the valve inlet screen
and by
properly installing
the

power element bulb.

Attachment
of the
expansion valve bulb
to the
evap-

orator outlet line
is
very critical.
The
bulb must be

attached tightly
to the
line
and
must make good contact

with
the
line along
the
entire length
of
the bulb. A loose
bulb will result
in
high
low
side pressures and poor

cooling.
On
bulbs located outside
the
evaporator case

insulation must be properly installed.

The external equalizer line shown
in
Figure
55 is
not

used
in the
Custom
and
Chevy
II
All-Weather systems.

Indications
of
expansion valve trouble provided by the

Performance Test are
as
follows:

VALVE STUCK OPEN
OR
BROKEN POWER

ELEMENT

Noisy Compressor.
•

No Cooling
-
Freeze
Up.

VALVE STUCK CLOSED
OR
PLUGGED SCREEN

Very Low Suction Pressure.

No Cooling.

Fig.
52-P.O.A. Valve Installed
Fig.
53—Thermostatic Switch Removal

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-43

LOW PRESSURE

CONTROL
HIGH PRESSURE

CONTROL

3

VACUUM

CONTROL
4

FREON

CONTROL

Fig,
56—Charging Station Controls

3.
When the pressure is reduced to below 100 pounds

on the high pressure gauge, open the low pressure

gauge valve and continue discharging until all re-

frigerant has been released. Close both gauge valves.

EVACUATING AND CHARGING THE SYSTEM

GENERAL NOTE: La all evacuating procedures

shown below, the specification of 26-28 inches

of Mercury vacuum is used. These figures are

only attainable at or near Sea Level Elevation.

For each 1000 feet above sea level where this

operation is being performed, the specifications

should be lowered by 1 inch. Example: at 5000

ft. elevation, only 21 to 23 inches of vacuum can

normally be obtained.

Whenever the air conditioning system is open for any

reason, it should not be put into operation again until it

has been evacuated to remove air and moisture which

may have entered the system.

The following procedures are based on the use of the

J-8393 Charging Station.

Filling Charging Cylinder

1.
Open control valve on refrigerant drum.

2.
Open valve on bottom of charging cylinder allowing

refrigerant to enter cylinder.

3.
Bleed cylinder valve on top (behind control panel) as

required to allow refrigerant to enter. When re-

frigerant reaches desired level (see "Air Condition-

ing System Capacities"), close valve at bottom of

cylinder and be certain bleed valve is closed

securely.

NOTE: It will be necessary to close bleed valve

periodically to allow boiling to subside to check

level in sight glass.

Installing Charging Station to System

1.
Be certain all valves on charging station are closed.

2.
Connect high pressure gauge line to high pressure

gauge fitting. (See "Installing Gauge Set to Check

System Operations.")
3.
See Figure 56. Turn high pressure control (2) one

turn counter-clockwise (open). Crack open low pres-

sure control (1) and allow refrigerant gas to hiss

from low pressure gauge line for three seconds,

then connect low pressure gauge line to low pressure

gauge fitting.

4.
System is now ready for performance testing.

Evacuating and Charging System

1.
Install charging station as previously described.

Refer to Figure 56 and 57 while performing the

following operation.

2.
Remove Low Pressure gauge line from compressor.

3.
Crack open high (2) and low (1) pressure control

valves, and allow refrigerant gas to purge from

system. Purge slow enough so that oil does not

escape from system along with Refrigerant.

4.
When refrigerant flow stops, connect Low Pressure

gauge line to compressor.

5.
Turn on vacuum pump and open Vacuum Control

Valve (3).

6. With system purged as above, run pump until 28-29

inched of vacuum is obtained. Continue to run pump

for 15 minutes after the system reaches 28-29 inches

vacuum.

7.
If 28-29 inches cannot be obtained, close Vacuum

Control Valve (3) and shut off vacuum pump. Open

Refrigerant Control Valve (4) and allow 1/2 pound of

R-12 to enter system. Locate and repair all leaks.

8. After evacuating for 15 minutes, add 1/2 pound of

R-12 to system as described in Step 7 above. Purge

this 1/2 pound and reevacuate for 5 minutes. This

second evacuation is to be certain that as much con-

tamination is removed from the system as possible.

9. Only after evacuating as above, system is ready for

charging. Note reading on sight glass of charging

cylinder. If it does not contain a sufficient amount

for a full charge, fill to the proper leveL

10.
With High and Low pressure Valves (1 and 2) open,

close Vacuum Control Valve (3) and open Freon

Control Valve (4). Operating the heater and air

conditioner blower with the controls set for cooling

will help complete the charging operation.

NOTE: If the charge will not transfer com-

pletely from the station to the system, close

the high pressure valve at the gauge set, set

the air conditioning controls for cooling, check

that the engine compartment is clear of ob-

structions, and start the engine. Compressor

operation will decrease the low side pressure

in the system.

System is now charged and should be performance

tested before removing gauges.

CHECKING OIL

In the six cylinder compressor it is not recommended

that the oil be checked as a matter of course. Gener-

ally, compressor oil level should be checked only where

there is evidence of a major loss of system oil such as

might be caused by:

• A broken refrigerant hose.

• A severe hose fitting leak.

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-45

• A very badly leaking compressor seal.

• Collision damage to the system components.

As a quick check on compressor oil charge, with the

engine off, carefully crack open the oil drain plug on the

bottom of the compressor. If oil comes out, the com-

pressor has the required amount of oil To further check

the compressor oil charge, should the above test show

insufficient oil, it is necessary to remove the compressor

from the vehicle, drain and measure the oil.

Checking Compressor Oil Charge

1.
Run the system for 10 minutes at 500-600 engine

rpm with controls set for maximum cooling and

high blower speed.

2.
Turn off engine, discharge the system, remove

compressor from vehicle, place it in a horizontal

position with the drain plug downward. Remove the

drain plug and, tipping the compressor back and

forth and rotating the compressor shaft, drain the

oil into a clean container, measure and discard the

oiL

3.
a. If the quantity drained was 4 fluid oz. or more,

add the same amount of new refrigerant oil to

the replacement compressor.

b.
If the quantity drained was less than 4 fluid oz.,

add 6 fluid oz. of new refrigeration oil to the

replacement compressor.

c. If a new service compressor is being installed,

drain all oil from it and replace only the amount

specified in Steps 3a and 3b above.

d. If a field repaired compressor is being installed,

add an additional 1 fluid oz. to the compressor.

4.
In the event that it is not possible to idle the com-

pressor as outlined in Step 1 to effect oil return to

it, proceed as follows:

a. Remove the compressor, drain, measure and

discard the oil.

b.
If the amount drained is more than 1-1/2 fluid

oz.
and the system shows no signs of a major

leak, add the same amount to the replacement

compressor.

c. If the amount drained is less than 1-1/2 fluid oz.

and the system appears to have lost an excessive

amount of oil add 6 fluid oz. of clean refrigeration

oil to replacement compressor, 7 fluid oz. to a

repaired compressor.

If the oil contains chips or other foreign ma-

terial, replace the receiver-dehydrator and flush
or replace all component parts as necessary. Add

the full specified volume of new refrigeration oil

to the system.

5.
Add additional oil in the following amounts for any

system components being replaced.

Evaporator 3 fluid oz.

Condenser . . . . ... . . . . . . 1 fluid oz.

Receiver-Dehydrator ....... 1 fluid oz.

NOTE: When adding oil to the compressor, it

will be necessary to tilt the rear end of the

compressor up so that the oil will not run out

of the suction and discharge ports. Do not set

the compressor on the shaft end.

Adding Oil to the System

The system should be completely assembled and un-

charged before adding oil. Use only uncontaminated

refrigerant oil (525 viscosity) and add as follows:

1.
Connect the low pressure line from the gauge set

to the low pressure gauge fitting on the P.O.A.

valve (Four-Season) or low pressure fitting on the

compressor connector Mock (Universal System).

2.
Connect the high pressure line from the charging

station gauge set to the compressor muffler or high

pressure side of the connector block.

3.
Disconnect the high pressure line from the gauge set,

make certain that the line is clean, and place the

end in a graduated container.

4.
Pour enough refrigerant oil into the container so

that the required volume may be drawn into the

system by the high pressure hose.

5.
Close the high pressure valve at the gauge set,

and open the low pressure valve.

6. Operate the vacuum pump to drop the pressure within

the system and cause atmospheric pressure to force

oil through the high pressure line into the system.

When the oil level has dropped the required volume,

pull the line out of the oil container and continue

vacuum pump operation to force the oil contained

in the line into the system.

7.
Shut off the vacuum pump and connect ttye high

pressure line to the gauge set. Open the high

pressure valve and evacuate the system through

the high and low pressure sides of the system.

Complete the charging operation as outlined in Step

10 under "Evacuating and Charging System".

COMPONENT REPLACEMENT AND MINOR REPAIRS

REFRIGERANT LINE CONNECTIONS

"O"
Rings

Always replace the "O" ring when a connection has

been opened. When replacing the "O" ring, first dip it

in refrigeration oil. Always use a backing wrench on

"O"
ring fittings to prevent the pipe from twisting and

damaging the "O" ring. Do not overtighten. Correct

torque specifications are as follows:
Metal

Tube

O.D.

1/4

3/8

1/2

5/8

3/4
Thread and

Fitting

Size

7/16

5/8

3/4

7/8

1-1/16
Steel

Tubing

Torque*

13

33

33

33

33
Alum.

Tubing

Torque*

6

12

12

20

25

* Pound Feet

CHEVROLET CHASSIS SERVICE

HEATER AND AIR CONDITIONING 1A-49

CHEVROLET

CHEVELLE

CHEVY II

CAMARO
the last possible moment. Be certain that the

direction of flow is correct before connecting

the pipes.

Chevrolet, Chevelle, Chevy II, and Camaro

Replacement

1.
Remove the receiver inlet and outlet connections and

the two receiver to fender skirt attaching screws.

2.
Carefully remove the receiver-dehydrator from the

vehicle.

3.
Replace the new receiver~dehydrator assembly in

the vehicle and install all attaching screws and re-

frigerant lines.

4.
Add one fluid oz. refrigerant oil, evacuate and charge

the system.

Corvette

Replacement

1.
Purge the system of refrigerant.

2.
Disconnect the "O" ring inlet

hose clamp outlet connection

openings.

3.
Remove the receiver-dehydrator to radiator support

bracket screws (production engine) or receiver-

dehydrator to condenser bracket screws (optional

engine) and remove the unit from the car.

4.
Install the new receiver-dehydrator applying 30 in.

lbs.
torque to the attaching screws.
connection and the

and tape the hose

NOTE:
Do not uncap the new receiver-

dehydrator until the last instant before

installation.

5.

2.

3.

Fig.
63—
Receiver-Dehydrator Mounting (Chevrolet,

Chevelle/ Chevy II, Camaro)
Connect the high pressure lines at the inlet (use a

new "O" ring and torque connection to 13 ft. lbs.)

and outlet (torque screw to 25 in. lbs.).

6. Add one fluid oz. refrigerant oil, evacuate, charge

and check the system.

Sight Glass Replacement-All Vehicles

If damage to the sight glass should occur, a new sight

glass kit should be installed. The kit contains the sight

glass,
seal and retainer. (See Figure 65.)

1.
Purge system.

Remove the sight glass retainer nut using a screw

driver and remove old glass and seal.

Install the new glass and seal and retainer nut, being

careful not to turn the nut past the face of the hous-

ing. To do so may damage the "O" ring seal.

4.
Evacuate and recharge the system.

EVAPORATOR

Chevrolet and Camaro Four-Season System

The evaporator and blower case assembly is designed

so that the core may be removed without the need for

removing the entire unit from the vehicle. Instead,

only the side cover must be removed.

Removal and Installation of Entire Assembly

1.
Remove the inlet line at the expansion valve and the

suction throttling valve outlet connection.

2.
Remove the electrical connector from the blower

motor.

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-54

Fig.
71-Wiring-AH Weather (Chevy II)

1.
Loosen the lock screws and remove the two control

knobs from the front of the evaporator unit. Then

use a suitable spanner wrench to remove the two

nuts beneath the control knobs.

2.
Remove the screws (located in the outer ball outlets)

attaching the face plate.to the evaporator case. Then

remove the face plate and, reaching through this

opening, carefully remove the plug attaching the

thermostatic switch capillary tube to the evaporator

core.

3.
Turning the unit over, remove the screws attaching

the back cover and gasket to the case and remove

the cover and gasket.

4.
From the top of the case, remove the screws attach-

ing the evaporator core brackets to the case.

5.
Carefully draw the core and expansion valve assem-

bly out of the case.

NOTE: The air conditioning "on" door bowden

cable, which extends through the core, will also

be removed at this time.

6. Remove the expansion valve power element from

the low pressure line.
7.
Disconnecting the high pressure and low pressure

lines from the valve, remove the valve from the

core.

8. At this point either the expansion valve, evaporator

core or both may be replaced.

a. If replacing the expansion valve, use new etO"

rings and make the connections carefully to

eliminate possible refrigerant leaks. Position

the power element bulb so that it lies flush with

the low pressure line and has the insulating

material properly in place.

b.
If the evaporator core is to be replaced, it will

be necessary to remove the air conditioning

door bowden cable from the core and install it

in the same location in the replacement core.

If no passage has been provided for this purpose

in the replacement core, a pointed instrument

such as a pencil may be forced through core

vanes at the proper location to provide the re-

quired opening. Also remove the spacer bracket,

nut and screw from the inlet and outlet pipes of

the evaporator core and place them in a like

position on the replacement core.

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-71

SUN-AMBIENT

SENSOR AND COMPRESSOR

CLUTCH SWITCH

HIGH BLOWER

DELAY RELAY

THERMAL

VACUUM

VALVE

Fig.
102-Comfortron Underhood Wiring

use when inspecting a damaged vehicle equipped with air

conditioning.

1.
Remove the drive belt. Cut belt off if necessary.

2.
Visually inspect the condenser, receiver-dehydrator,

compressor, mounting brackets, conditioning unit, all

connecting lines, and all controls to determine the

extent and nature of the damage.

a. No repairs, such as soldering, welding or braz-

ing, should be attempted on the condenser be-

cause of its construction. If the vapor passages

in the horizontal tubes or return bends or mani-

folds have been damaged in any way, the con-

denser should be replaced with a new one.

b.
The receiver-dehydrator should be replaced if

there is any evidence of its having sustained

either internal damage or a fracture at any of

the lines or welded joints or if the system has

been exposed to the atmosphere for an undeter-

mined period of time.

c. Examine the compressor for any visible external

damage.

d. The evaporator should be examined for damage

and, if necessary, removed or replaced or the

entire unit processed where damaged or exposed

to the atmosphere.

e. All connecting lines and flexible hoses should be

examined throughout their entire length for dam-

age.
If damaged in any manner, replace with new

lines.
f. Check all controls and connecting wires for

damage and replace with new parts where needed.

g. Check the clutch pulley for proper operation and

freedom from damage.

3.
Install gauge set.

4.
Purge the system. Pressure should not exceed 3 to

5 pounds.

5. Remove the compressor from mounting and remove

the oil test fitting.

6. Pour out the oil into a clean glass container and ex-

amine it for any foreign substance such as dirt,

water, metal particles, etc. If any of these are

present, the compressor and receiver-dehydrator

should be replaced and the other system components

should be flushed with liquid refrigerant.

7. If the oil is clean and free of any harmful substance,

replace oil with Frigidaire Oil available through

Parts Stock.

NOTE:
If the system components have been

replaced or flushed, replace the full charge of

oil. If not, add no more fresh oil than was

drained in Step 6.

8. Charge up the compressor to drum or can pressure

and leak test the compressor seals prior to in-

stallation of compressor.

9. Reinstall the compressor and evacuate the system

by following the Evacuating Procedure.

CHEVROLET CHASSIS SERVICE MANUAL