
GENERAL INFORMATION 0-8
nun
Illllfl Q
i,,,,,,,,
DRIVE ON HOIST
BUMPER JACK LIFTING AT FRAME ATTACHMENT ONLY
FLOOR JACK OR HOIST LIFT
Fig.
22—Vehicle Lifting Points—Chevelle
TOWING THE CAMARO
The recommended method for towing the Camaro is
follows.
Front
Connect standard chain hooks near the outer ends of
the front suspension lower control arms in between the
coil springs and the stabilizer bar link bolt (fig. 23).
The chains should be attached to the lower lifting sling
bar so that when the vehicle is raised the rubber straps
protect the front valance panel (fig. 24). Caution should
be exercised when attaching the lower lifting bar that the
upper lifting bar does not damage the hood header panel.
Fig. 23—Attachment of Towing Chain Hooks
to Lower Control Arms
CHEVROLET CHASSIS SERVICE MANUAL

LUBRICATION 0-13
LUBRICATION
INDEX
Page
Engine Crankcase Oil . 0-13
Crankcase Capacities. . 0-13
Lubrication . ,
•
o-13
SAE Viscosity Oils 0-13
Types of Oils 0-14
Maintaining Oil Level 0-14
Oil and Filter Change Intervals 0-14
Oil.
. . ...:.. 0-14
Filter o-14
Crankcase Dilution . 0-14
Automatic Control Devices to Minimize
Crankcase Dilution 0-14
Crankcase Breather Cap 0-14
Crankcase Ventilation System 0-15
Valve Type 0-15
Fuel Filter 0-15
Air Cleaner . 0-15
Polyurethane Type 0-15
Oil Wetted Paper Element Type 0-15
Battery Terminal Washers 0-15
Page
Distributor 0-15
Rear Axle and 3-Speed and Overdrive
4-Speed Transmission 0-15
Recommended Lubricants 0-15
Multi-Purpose Gear Lubricants 0-15
Lubricant Additions 0-15
Lubricant Changes 0-15
Powerglide Transmission 0-15
Turbo Hydra-Matic 0-16
Front Wheel Bearings 0-16
Manual Steering Gear . . . . 0-16
Power Steering 0-16
Air Conditioning 0-16
Brake Master Cylinder. 0-16
Parking Brake 0-16
Clutch Cross-Shaft , 0-16
Chassis Lubrication 0-16
Lubrication Diagrams . . 0-19
Body Lubrication (Chevrolet, Chevelle, Chevy n, Camaro). 0-20
Body Lubrication Points (Corvette) . 0-21
The selection of the proper lubricant and its correct
application at regular intervals does much to increase the
life and operation of all moving parts of the vehicle.
Consequently, it is important that the correct grade of
oil or grease, as noted in the following pages, be used.
ENGINE CRANKCASE OIL
Crankcase Capacity
4 Cylinder 4 qt.
6 Cylinder 4 qt.
8 Cylinder (283) 4 qt.
8 Cylinder (327) 4 qt.
8 Cylinder (350) 4 qt.
8 Cylinder (396) 4 qt.
8 Cylinder (427) Chevrolet 4 qt.
8 Cylinder (427) Corvette 5 qt.
For 4 Cyl. Add .5 qt. with filter change;
1 qt. for 6 and 8 Cyl. engines.
Lubrication
Crankcase oil should be selected to give the best per-
formance under the climatic and driving conditions in the
territory in which the vehicle is driven.
During warm or hot weather, an oil which will provide
adequate lubrication under high operating temperatures
is required.
During the colder months of the year* an oil which will
permit easy starting at the lowest atmospheric tempera-
ture likely to be encountered, should be used.
When the crankcase is drained and refilled, the crank-
case oil should be selected, not on the basis of the exist-
ing temperature at the time of the change, but on the
lowest temperature anticipated for the period during
which the oil is to be used.
Unless the crankcase oil is selected on the basis of
viscosity or fluidity of the anticipated temperature, dif-
ficulty in starting will be experienced at each sudden
drop in temperature.
SAE Viscosity Oils
SAE Viscosity Numbers indicate only the viscosity or
body of the oil, that is, whether an oil is a light or a
heavy body oil, and do not consider or include other
properties or quality factors.
The lower SAE Viscosity Numbers, such as SAE 5W
and SAE 10W which represent the light body oils, are
recommended for use during cold weather to provide
easy starting and instant lubrication. The higher SAE
Viscosity Numbers such as SAE 20 and SAE 20W, which
represents heavier body oils, are recommended for use
during warm or hot weather to provide improved oil
economy and adequate lubrication under high operating
temperatures.
Oils are available which are designed to combine the
easy starting characteristics of the lower SAE Viscosity
Number with the warm weather operating characteristics
of the higher SAE Viscosity Number. These are termed
"multi-viscosity oils," SAE 5-10W, SAE 5W-20, SAE
10W-20W, and SAE 10W-30.
The following chart will serve as a guide for the
selection of the correct SAE Viscosity Number for use
under different atmospheric temperature ranges, and
suggests the appropriate SAE Viscosity Numbers when
multi-viscosity oils are used.
Lowest Anticipated
Temperature
During Time
Oil Will Be
in Crankcase
32°F.
0°F.
Below 0°F.
Recommended
SAE Viscosity
Oils
SAE 20 or 20W
SAE 10W
SAE 5W
Recommended
SAE
Multi-
Viscosity
Oils
SAE 10W-30 .
SAE 10W-30
SAE 5W-20
SAE 30 or 10W-30 is recommended when most of the
driving is at high speeds and/or at temperatures above
90
°F.
CHEVROLET CHASSIS SERVICE MANUAL

LUBRICATION 0-14
SAE 5W-30 oils may be used during periods when
temperatures of 32° and below are to be expected.
Types of Oils
In service, crankcase oils may form sludge and varnish
and under some conditions, corrosive acids unless pro-
tected against oxidation.
To minimize the formation of these harmful products
and to assure the use of oil best suited for present day
operating conditions, automobile manufacturers have de-
veloped a series of sequence tests designed to evaluate
the ability of any oil to properly lubricate automobile
engines.
It is recommended that only those oils which are
certified by their suppliers as meeting or exceeding the
maximum severity requirements of these sequence tests
(or GM Standard 4745-M) be used in Chevrolet engines.
Certified sequence tested oils will be described as such
on their containers.
Maintaining Oil Level
The oil gauge rod is marked "Full" and "Add Oil."
These notations have broad arrows pointing to the level
lines.
The oil level should be maintained between the
two lines, neither going above the "Full" line nor under
the "Add Oil" line. DO NOT OVERFILL. After operating
vehicle allow a few minutes for oil to return to crankcase
before checking oil level.
Check the oil level frequently and add oil when
necessary.
Oil and Filter Change Intervals
NOTE:
Under prolonged dusty driving condi-
tions,
it is recommended that these operations
be performed more often.
OIL
To insure continuation of best performance, low main-
tenance cost and long engine life, it is necessary to
change the crankcase oil whenever it becomes contami-
nated with harmful foreign materials. Under normal
driving conditions draining the crankcase and refilling
with fresh oil every 60 days or every 6000 miles which-
ever occurs first, is recommended.
It is always advisable to drain the crankcase only after
the engine has become thoroughly warmed up or reached
normal operating temperature. The benefit of draining is,
to a large extent, lost if the crankcase is drained when
the engine is cold, as some of the suspended foreign
material will cling to the sides of the oil pan and will not
drain out readily with the cold, slower moving oil.
OIL FILTER
Change engine oil filter every 6000 miles or every 6
months, whichever occurs first.
NOTE:
For Vehicles in heavy duty operation
involving continuous start-stop or prolonged idl-
ing, engine oil should be changed after 2500-
3000 miles of operation. The filter should be
changed after 5000-6000 miles of operation.
Crankcase Dilution
Probably the most serious phase of engine oil deterio-
ration is that of crankcase dilution which is the thinning
of the oil by fuel vapor leaking by pistons and rings and
mixing with the oil and by condensation of water on the
cylinder walls and crankcase.
Leakage of fuel, or fuel vapors, into the oil pan occurs
mostly during the "warming up" period when the fuel is
not thoroughly vaporized and burned. Water vapor enters
the crankcase through normal engine ventilation and
through exhaust gas blow-by. When the engine is not
completely warmed up, these vapors condense, combine
with the condensed fuel and exhaust gases and form acid
compounds in the crankcase.
As long as the gases and internal walls of the crank-
case are hot enough to keep water vapor from con-
densing, no harm will result. However, when the engine
is run in low temperatures moisture will collect and
unite with the gases formed by combustion resulting in
an acid formation. The acid thus formed is likely to
cause serious etching or pitting which will manifest itself
in excessively rapid wear on piston pins, camshaft
bearings and other moving parts of the engine, oftentimes
causing the owner to blame the car manufacturer or the
lubricating oil when in reality the trouble may be traced
back to the character of fuel used, or a condition of the
engine such as excessive blowby or improper carburetor
adjustment.
Automatic Control Devices to Minimize
Crankcase Dilution
All engines are equipped with automatic devices which
aid greatly in minimizing the danger of crankcase
dUution.
The thermostat, mounted in the cylinder head water
outlet, restricts the flow of water to the radiator until a
predetermined temperature is reached, thus minimizing
the length of time required to reach efficient operating
temperature, reducing the time that engine temperatures
are conducive to vapor condensation.
A water by-pass is included in the cooling system,
utilizing a hole in the front of, the cylinder block. This
allows a limited circulation of coolant, bypassing the
thermostat until thermostat opening temperatures are
reached. This system provides a uniform coolant tem-
perature throughout the engine, eliminating localized
hot-spots, improving exhaust valve life, provides fast
warmrup of lubricating oil and fast temperature rise in
the coolant which provides fast heater operation in cold
weather.
A thermostatic heat control on the exhaust manifold
during the warming up period, automatically directs the
hot exhaust gases against the center of the intake mani-
fold, greatly aids in proper vaporization of the fuel.
An automatic choke reduces the danger of raw or
unvaporized fuel entering the combustion chamber and
leaking into the oil reservoir.
An.
efficient crankcase ventilating system drives off
fuel vapors and aids in the evaporation of the raw fuel
and water which may find its way into the oil pan.
CRANKCASE BREATHER CAP
Clean and re-oil at every oil change..
CHEVROLET CHASSIS SERVICE MANUAL

LUBRICATION 0-15
CRANKCASE VENTILATION VALVE
VALVE TYPE
NOTE: Under prolonged dusty driving condi-
tions,
it is recommended that these operations
be performed more often. Every 12,000 miles
or 12 months the valve should be replaced.
Connecting hoses, fittings, flame arrestor and
crankcase breather cap (where used) should be
cleaned. At every oil change the system should
be tested for proper function and serviced, if
necessary.
FUEL FILTER
Replace filter element located in carburetor inlet if
flooding occurs, if engine surges during constant speed
operation (pulsating effect) or if poor performance is
experienced during acceleration or at higher speeds.
AIR CLEANER
NOTE: Under prolonged dusty driving condi-
tions,
it is recommended that these operations
be performed more often.
POLYURETHANE TYPE-
Every 12,000 miles clean element in solvent, squeeze
out solvent, then soak in engine oil and squeeze out
excess.
OIL WETTED PAPER ELEMENT TYPE-
First 12,000 miles inspect or test element; if satis-
factory, re-use element but recheck every 6,000 miles
until replaced. Element must not be washed, oiled,
tapped or cleaned with an air hose.
BATTERY TERMINAL WASHERS
Battery terminals have felt washers between top of
case and cable connections to minimize corrosive action
of battery acid. These felt washers should be saturated
with engine oil every 6,000 miles.
DISTRIBUTOR
4 and 6-Cylinder Engine—Remove distributor cap and
rotate lubricator 1/2 turn at 12,000 mile intervals. Re-
place at 24,000 mile intervals.
8-Cylinder Engine—Change cam lubricator end for end
at 12,000 mile intervals. Replace at 24,000 mile
intervals.
REAR AXLE AND 3-SPEED AND
OVERDRIVE, 4-SPEED TRANSMISSIONS
The passenger car operates under the most severe
lubrication conditions at high speed and requires a hypoid
lubricant which will meet this condition.
Recommended Lubricants
Standard Rear Axles—SAE 90 "Multi-Purpose" gear
lubricant.
Positraction Rear Axles—Use special Positraction
lubricant.
CAUTION: Straight Mineral Oil gear lubricants
must not be used in hypoid rear axles.
Transmissions—SAE 90 "Multi-Purpose" gear
lubricant.
The SAE 90 viscosity grade is recommended for year
round use. However, when extremely low temperatures
are encountered for protracted periods during the winter
months, the SAE 80 viscosity grade may be used.
"Multi-Purpose" Gear Lubricants
Gear lubricants that will satisfactorily lubricate hypoid
rear axles have been developed and are commonly re-
ferred to as ' 'Multi-Purpose" gear lubricants meeting
U.S.
Army Ord. Spec. MIL-L-2105B.
These lubricants can also be satisfactorily used in
manual transmissions.
CAUTION: With Positraction rear axles use
special Positraction lubricant.
"Multi-Purpose" gear lubricants must be manufac-
tured under carefully controlled conditions and the
lubricant manufacturer must be responsible for the
satisfactory performance of his product. His reputation
is the best indication of quality.
Lubricant Additions
The lubricant level in the axle and transmission hous-
ings should be checked periodically. (Every 6,000 miles.)
It is recommended that any additions required to bring
up the lubricant level be made using the same type lubri-
cant already in the housing.
When checking lubricant level in transmission or rear
axle the unit being cheeked should be at operating
temperature. With unit at operating temperature the
lubricant should be level with bottom of the filler plug
hole.
If the lubricant level is checked with the unit cold
the lubricant level should be 1/2 inch below the filler
plug hole.
Lubricant Changes
The rear axle lubricant does not require changing for
the life of the vehicle. If additions are needed, or when
refilling the axle after service procedures, use lubricants
described above.
POWERGLIDE TRANSMISSION
NOTE: Every 12,000 miles, it is recommended
that the Powerglide low band be adjusted as
specified in Section 7 of this manual.
Every 6,000 miles--Check fluid level on dipstick with
engine idling, selector lever in neutral position, parking
brake set and transmission at operating temperature. If
fluid level is below full mark on dip stick, adding a small
amount of Automatic Transmission Fluid, General Motors
Automatic Transmission Fluid (Part Numbers 1050568-
69,
70) is recommended. If this fluid is not obtainable,
use Automatic Transmission Fluid Type 'A' bearing the
mark AQ-ATF followed by a number and the suffix letter
'A'.
Recheck fluid level on dip stick and again add a
small amount of fluid if needed to bring level to full
mark. DO NOT OVERFILL.
CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-26
clockwise for medium and high blower speed, as
desired. Low blower speed is automatic during
cooling operations.
4.
"Def-Pull". This knob should be pushed fully in.
Additional Cooling Hints
1.
The center barrel outlet in the dash may be rotated
to deflect air as desired or used to act as a shut off
door.
2.
The right and left ball outlets may be rotated to
deflect air in the direction desired. Each outlet has
a shut off valve operated by a knob approximately
4 in. inboard. When the knob is horizontal, the valve
is open.
3.
There are two (2) additional outlets in the bottom of
the ducts approximately 6" inboard from the valve
knobs. A rotating cover will open these outlets to
provide cool air for the feet if desired.
4.
When first entering a very warm car, open the
windows for a few minutes until the interior of the
car has cooled off.
Heating
1.
"Air Pull-Fan". Pull this knob fully out. Rotate
the knob clockwise for low, medium or high blower
speed as desired. If just a small amount of heat is
desired, leave the fan on low or medium speed and
regulate the temperature with the "Cool In-Hot Pull"
knob.
2.
"Air Cond-Pull". This knob should normally be
pushed fully in. However, during cool, damp days
it is possible, by pulling this knob fully out, to de-
humidify the air by passing it through the evaporator
core before reheating to the desired outlet
temperature.
3.
"Cool In-Hot Pull". Pull this knob out as far as
necessary to provide the temperature desired.
4.
"Def-Pull". Pull this knob all the way out for
maximum defrosting or de-icing. When the knob is
partly out, a portion of the hot air is used for de-
frosting and the balance is discharged through the
heater outlet.
GENERAL INFORMATION
In any vocation or trade, there are established proce-
dures and practices that have been developed after many
years of experience. In addition, occupational hazards
may be present that require the observation of certain
precautions or use of special tools and equipment. Ob-
serving the procedures, practices and precautions of
servicing refrigeration equipment will greatly reduce the
possibilities of damage to the customers' equipment as
well as virtually eliminate the element of hazard to the
serviceman.
PRECAUTIONS IN HANDLING REFRIGERANT-12
Refrigerant-12 is transparent and colorless in both the
gaseous and liquid state. It has a boiling point of 21.7^
below zero and, therefore, at all normal temperatures
and pressures it will be a vapor. The vapor is heavier
than air and is noninflammable, nonexplosive, non-
poisonous (except when in contact with an open flame)
and noncorrosive (except when in contact with water).
The following precautions in handling R-12 should be
observed at all times.
• All refrigerant drums are shipped with a heavy metal
screw cap. The purpose of the cap is to protect the
valve and safety plug from damage. It is good .prac-
tice to replace the cap after each use of the drum.
• If it is ever necessary to transport or carry a drum
or can of refrigerant in a car, keep it in the luggage
compartment. Refrigerant should not be exposed to
the radiant heat from the sun for the resulting in-
crease in pressure may cause the safety plug to
release or the drum or can to burst..
• Drums or disposable cans should never be subjected
to high temperature when adding refrigerant to the
system. In most instances, heating the drum or can
is required to raise the pressure in the container
higher than the pressure in the system during the
operation. It would be unwise to place the drum on a
gas stove, radiator or use a blow torch while pre-
paring for the charging operation, for a serious ac-
cident can result. Don't depend on the safety
plug - many drums have burst when the safety plug
failed.' Remember, high pressure means that great
forces are being exerted against the walls of the
container. A bucket of warm water, not over 125°F,
or warm wet rags around the container is all the heat
that is required.
• Do not weld or steam clean on or near the system.
Welding or steam cleaning can result in a dangerous
pressure buildup in the system.
• When filling a small drum from a large one, never
fill the drum completely. Space should always be
allowed above the liquid for expansion. If the drum
were completely full and the temperature was in-
creased, hydraulic pressure with its tremendous
force would result.
• Discharging large quantities of R-12 into a room can
usually be done safely as the vapor would produce
no ill effects, however, in the event of an accidental
rapid discharge of the system it is recommended
that inhalation of large quantities of R-12 be avoided.
This caution is especially important if the area con-
tains a flame producing device such as a gas heater.
While R-12 normally is nonpoisonous, heavy con-
centrations.. of it in contact with a live flame will
produce a toxic gas. The same gas will also attack
all bright metal surfaces.
• Protection of the eyes is of vital importance! When
working around a refrigerating system, an accident
may cause liquid refrigerant to hit the face. If the
eyes are protected with goggles or glasses, no
serious damage can result. Just remember, any
R-12 liquid that you can touch or that touches you is
at least 21.7"F. below zero. The eyeballs can't take
much of this temperature. If R-12 liquid should
strike the eyeballs, here is what to do:
1.
Keep calm.
2.
Do not rub the eyes! Splash the affected area with
quantities of cold water to gradually get the tem-
perature above the freezing point. The use of min-
eral, cod liver or an antiseptic oil is important in
CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-29
time as possible will be required to perform the
operation. Don't leave the system open any longer
than is necessary.
• Finally, after the operation has been completed and
the system sealed again, air and moisture should be
evacuated from the system before recharging.
GAUGE SET
The gauge set (fig. 41) is used when purging, evacua-
ting, charging or diagnosing trouble in the system. The
gauge at the left is known as the low pressure gauge.
The face is graduated into pounds of pressure and, in
the opposite direction, in inches of vacuum. This is the
gauge that should always be used in checking pressures
on the low pressure side of the system. When all parts of
the system are functioning properly the refrigerant
pressure on the low pressure side never fails below 0
pounds pressure. However, several abnormal conditions
can occur that will cause the low pressure to fall into a
partial vacuum. Therefore, a low pressure gauge is
required.
The high pressure gauge is used for checking pres-
sures on the high pressure side of the system.
The connection at the left is for attaching the low
pressure gauge line and the one at the right the high
pressure gauge line. The center connector is common to
both and is for the purpose of attaching a line for adding
refrigerant, discharging refrigerant, evacuating the sys-
tem and other uses. When not required, this line or
connection should be capped.
NOTE:
Gauge fitting connections should be in-
stalled hand tight only and the connections leak
tested before proceeding.
The hand shutoff valves on the gauge manifold do not
control the opening or closing off of pressure to the
gauges. They merely close each opening to the center
connector and to each other. During most diagnosing
and service operation, the valves must be closed. The
only occasion for opening both at the same time would be
to bypass refrigerant vapor from the high pressure to
the low pressure side of the system, or in evacuating
both sides of the system.
CHARGING STATION
The J-8393 Charging Station is a portable assembly of
a vacuum pump, refrigerant supply, gauges, valves, and
most important, a five (5) pound metering refrigerant
charging cylinder. The use of a charging ey'inder elim-
inates the need for scales, hot water pails, etc.
The chief advantage of this unit is savings. A very
definite savings in refrigerant and time can be obtained
by using this unit. Since the refrigerant is metered into
the system by volume, the correct amount may be added
to.
the system and charged to the customer. This, coupled
with the fact that the unit remains "plumbed" at all times
and thus eliminates loss of refrigerant in purging of
lines and hooking-up, combines to enable the operator to
get full use of all refrigerant purchased by the
dealership.
All evacuation and charging equipment is hooked to-
gether in a compact portable unit (fig. 42) which brings
air conditioning service down to the basic problem of
hooking on two hoses, and manipulating clearly labeled
valves.
Fig.
42—System Charging Station
This will tend to insure that the job will be done without
skipping operations. As a result, you can expect to save
time and get higher quality work, less chance of an over
or undercharge, or comeback.
The pump mount is such that the dealer may use his
own vacuum pump. The gauges and manifold are in com-
mon use. Thus a current air conditioning dealer can use
the equipment on hand and avoid duplication.
LEAK TESTING THE SYSTEM
Whenever a refrigerant leak is suspected in the system
or a service operation performed which results in dis-
turbing lines or connections, it is advisable to test for
leaks.
Common sense should be the governing factor in
performing any leak test, since the necessity and extent
of any such test will, in general, depend upon the nature
of the complaint and the type of service performed on
the system. It is better to test and be sure, if in doubt,
than to risk the possibility of having to do the job over
again.
NOTE:
The use of a leak detecting dye within
the system is not recommended because of the
following reasons:
1.
Refrigerant leakage can exist without any oil leakage.
In this case the dye will not indicate the leak, how-
ever, a torch detector will.
2.
The addition of additives, other than inhibitors, may
alter the stability of the refrigeration system and
cause malfunctions.
3.
Dye type leak detectors which are insoluble form a
curdle which can block the inlet screen of the ex-
pansion valve.
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-47
are certain procedures, practices and precautions that
should be followed to prevent costly repairs, personal
injury or damage to equipment. For this reason it is
strongly recommended that the preceding information in
this section be studied thoroughly before attempting to
service the sytem.
Great emphasis must be placed upon keeping the sys-
tem clean. Use plugs or caps to close system components
and hoses when they are opened to the atmosphere. Keep
your work area clean.
In removing and replacing any part which requires
unsealing the refrigerant circuit the following operations,
which are described in this section, must be performed
in the sequence shown.
1.
Purge the system by releasing the refrigerant to the
atmosphere.
2.
Remove and replace the defective part.
3.
Evacuate and charge the system with R-12.
CAUTION: Always wear protective goggles
when working on refrigeration systems. Goggles
J-5453 are included in the set of air conditioning
special tools. Also, beware of the danger of
carbon monoxide fumes by avoiding running the
engine in closed or improperly ventilated
garages.
FOREIGN MATERIAL IN THE SYSTEM
Whenever foreign material is found in the system,
it must be removed before restoring the system to
operation.
In the case of compressor mechanical failure, perform
the following operations:
1.
Remove the compressor.
2.
Remove the receiver-dehydrator and discard me
unit.
3.
Flush the condenser to remove foreign material
which has been pumped into it.
4.
Disconnect the line from the receiver-dehydrator
at the inlet connection of the expansion valve. Inspect
the inlet screen for the presence of metal chips
or other foreign material. If the screen is plugged,
replace it. Reconnect the line to the expansion
valve.
5. Install a new receiver dehydrator.
6. Install the replacement compressor.
7. Add the necessary quantity of oil to the system (one
fluid ounce because of receiver-dehydrator replace-
ment plus the quantity needed for the replacement
compressor—see Checking Compressor Oil Charge
under Checking Oil.
8. Evacuate and charge the system.
9. Check system performance.
CONDENSER
Chevrolet
Replacement
1.
Remove the hood catch and hood catch - grille
support.
2.
With the system purged of refrigerant, disconnect
the inlet and outlet hose clamp connections and the
condenser to radiator support attaching screws.
3.
Remove the condenser from the vehicle.
NOTE:
If it is to be reused, cap or tape the
receiver-dehydrator inlet and outlet connections
at once.
4.
Install new condenser, position the assembly and
install the radiator support to condenser attaching
screws and replace all line connections.
5. Replace the hood catch and grille support and its
attaching bolts.
6. Replace the hood catch.
7. Evacuate, charge and check the system. Add one
fluid oz. refrigerant oil after installing a new
condenser.
Chevelle and Camaro
Replacement
1.
Remove the hood lock catch support and catch.
2.
With the system purged of refrigerant, disconnect
the inlet and outlet hose clamp connections and the
condenser to radiator support attaching screws.
3.
Remove the condenser from the vehicle.
NOTE:
Cap or tape the inlet and outlet con-
nections at once.
4.
Install new condenser, position the assembly and in-
stall the radiator support to condenser attaching
screws and replace all line connections.
5. Evacuate, charge and check the system. Add one
fluid oz. refrigerant oil after installing a new
condenser.
Chevy II
Replacement
1.
Purge the refrigerant from the system.
Fig.
59—Condenser Mounting (Chevrolet and Chevelle)
CHEVROLET CHASSIS SERVICE MANUAL