
HEATER
 AND AIR
 CONDITIONING
 1A-13
AIR CONDITIONING
INDEX
Page
General Description
 1A-13
Four-Season System
 1A-13
Controls
 1A-16
Comfortron System
 . 1A-18
System Components
 lA-19
Controls
 1A-20
Universal System
 . .
 1A-21
Chevy
 n
 All-Weather System
 •
 1A-21
Corvette Four-Season System
 . 1A-22
General Information
 . . . 1A-26
Precautions
 in
 Handling R-12
 1A-26
Precautions
 in
 Handling Refrigerant Lines
 1A-28
Maintaining Chemical Stability
 in the
Refrigeration System
 1A-28
Gauge
 Set 1A-29
Charging Station
 IA-29
Leak Testing
 the
 System
 1A-29
Vacuum Pump
 1A-30
Availability
 of
 Refrigerant-12
 . . 1A-30
Compressor
 Oil 1A-31
Compressor Serial Number
 1A-31
Inspection
 and
 Periodic Service
 1A-31
Pre-Delivery Inspection
 1A-31
6,000 Mile Inspection
 1A-32
Periodic Service
 , 1A-32
Installing Gauge
 Set to
 Check System Operation
 ....
 1A-32
Performance Test
 1A-32
Performance Data lA-r33
Comfortron System Operational Test
 1A-33
Chevrolet Comfortron Tester
 1A-34
Complete System Checks
 1A-35
Maintenance
 and
 Adjustments ......
 1A-37
Evaporator Comtrol Valve (POA)
 .
 1A-37 
Page
Thermostatic Switch
 1A-37
Expansion Valve
 1A-41
Engine Idle Compensator
 . . .
 1A-42
Evacuating
 and
 Charging Procedures
 1A-42
Purging
 the
 System
 1A-42
Evacuating
 and
 Charging
 the
 System
 1A-43
Checking
 Oil . 1A-43
Component Replacement
 and
 Minor Repair
 1A-45
Refrigerant Line Connections
 1A-45
Repair
 of
 Refrigerant Leaks
 1A-46
Preparing System
 for
 Replacement
 of
Component Parts
 . 1A-46
Foreign Material
 in the
 System
 .
 1A-47
Condenser
 .
 1A-48
Receiver-Dehydrator
 1A-48
Evaporator
 1A-49
Expansion Valve
 1A-57
Evaporator Control Valve (POA)
 1A-59
Thermostatic Switch
 or
 Blower Switch
 . .
 1A-59
All Weather-Pull Cable
 1A-61
Blower Assembly
 1A-62
Air Inlet Valve
 .
 1A-64
Blower
 and
 Evaporator Assembly
 1A-64
Air Distributor Assembly
 and
 Outlet Ducts ...... 1A-64
Comfortron Automatic Control Components
 1A-66
Collision Procedure lA-70
Four-Season Heater Components
 1A-73
Comfortron Heater Components
 . . . 1A-75
Compressor
 1A-76
Wiring Diagrams
 1A-78
Special Tools
 .
 1A-84
GENERAL DESCRIPTION
Four
 air
 conditioning systems
 are
 covered
 in
 this
section. They are:
1.
 The
 Four-Season System (Chevrolet, Chevelle,
Camaro and Corvette).
2.
 The Comfortron System (Chevrolet).
3.
 The All Weather System (Chevy n).
4.
 The Universal System (Chevrolet, Chevelle, Chevy
 n,
Camaro)
Underhood components (that
 is, the
 compressor,
 con-
denser
 and
 receiver-dehydrator)
 are
 much
 the
 same
 in
type,
 location
 and
 method
 of
 attachment
 on all of
 the
above systems. The six-cylinder reciprocating compres-
sor
 is
 bracket-mounted
 to the
 engine
 and
 belt driven
from
 the
 crankshaft pulley.
 The
 condenser
 is
 mounted
ahead
 of the
 engine cooling radiator
 and the
 receiver-
dehydrator
 is
 mounted
 in
 the refrigerant line downstream
of
 the
 condenser.
 All
 cooling system components
 are
connected by means
 of
 flexible refrigerant lines.
Evaporator size
 and
 location differ from system
 to
system
 as do
 methods
 of
 temperature control
 and air
supply
 and
 distribution.
FOUR-SEASON SYSTEM
The Four-Season system used
 in the
 Chevrolet,
Chevelle, Camaro,
 and
 Corvette vehicles
 may be
 iden-
tified
 by the
 fact that
 it
 uses
 an
 evaporator pressure
control known
 as the POA
 (Pressure Operated Absolute)
suction throttling valve. 
Both
 the
 heating
 and
 cooling functions
 are
 performed
by this system.
 Air
 entering
 the
 vehicle must pass
through
 the
 cooling unit (evaporator)
 and
 through
 (or
around)
 the
 heating unit,
 in
 that order, and the system
 is
thus referred to
 as a
 ''reheat" system.
The evaporator provides maximum cooling
 of the air
passing through
 the
 core when
 the air
 conditioning sys-
tem
 is
 calling
 for
 cooling.
 The
 control valve acts in the
system only
 to
 control
 the
 evaporator pressure
 so
 that
minimum possible temperature
 is
 achieved without core
freeze-up.
 The
 valve
 is
 preset,
 has no
 manual con-
trol,
 is
 automatically altitude compensated,
 and non-
repairable.
The heater core will be hot
 at
 all times since no water
valve
 is
 present
 in
 the system.
System operation
 is as
 follows (See Figure 24 and 25):
Air, either outside
 air or
 recirculated
 air
 enters
 the
system
 and is
 forced through
 the
 system by the blower.
As
 the air
 passes through
 the
 evaporator core,
 it
receives maximum cooling
 if
 the
 air
 conditioning controls
are calling
 for
 cooling. After leaving
 the
 evaporator,
the
 air
 enters
 the
 Heater
 and Air
 Conditioner Selector
Duct Assembly where,
 by
 means
 of
 manually operated
diverter doors,
 it is
 caused
 to
 pass through
 or to
 bypass
the heater core
 in the
 proportions necessary
 to
 provide
the desired outlet temperature. Conditioned airflow then
enters
 the
 vehicle through either
 the
 floor distributor
duct
 or the
 dash outlets. Remember that the heater core
CHEVROLET CHASSIS SERVICE MANUAL 

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-37
VACUUM SYSTEM COMPONENT FUNCTION
Component
Air Door Diaphragm
Power Servo
Vacuum Relay Valve
Mode Door Diaphragm
Defroster Diaphragm
Transducer
Thermo Vacuum Valve 
Vacuum Applied
Air Door Open to Outside Air
(Closed to Car Body)
Maximum Heat
Vacuum Applied to One Port Opens a Passage
Through the Valve to Allow Transducer Vacuum
to be Supplied to the Power Servo
Vacuum to Linkage Side
Air Flow Out Heater
Ducts
Full Airflow Out Heater
Outlet 
Vacuum to Covered Side
Airflow Out of Upper
Outlets
Full Airflow Out Defroster
Outlets (Full De-ice) 
No Vacuum Applied
Air Door Open to
Re circulated Air
(Open to Car Body)
Maximum Cooling
No Vacuum Applied Closes
Vacuum Supply to Power
Servo
Airflow Out of Upper and
Lower Outlets Door Open
1"
 from 100% Lower Out-
let Position
Airflow Divided 1/3 Out
Defroster Outlets 2/3
Out Heater Outlets
Supplies Modulated Vacuum to Power Servo
Zero Voltage Applied to Transducer
Results in Maximum Vacuum Supply 
10 Volts Applied to Transducer
Results in No Vacuum Supply
(Coolant Hot) Passes Vacuum When System is Calling For Outside Air
MAINTENANCE AND ADJUSTMENTS
EVAPORATOR CONTROL VALVE (POA)
(Chevrolet, Chevelle, Comoro, and Corvette
Four Season) (Chevrolet Comfortron)
The only check for proper POA valve operation is to
check the suction pressure at the valve as during a
performance test. The POA valve is an absolute valve
and will provide different gauge readings based on the
altitude where the readings are being taken. Correct
gauge reading at sea level is 29.5 psig. Gauge readings
will be one-half psi higher for each additional 1000 feet
of elevation. The following table lists gauge readings at
different altitudes. If a valve gives improper gauge
readings, it must be replaced since it is not repairable
or adjustable.
29.5
30.0
30.5
31.0
31.5
32.0
32.5
33.0
33.5
34.0
34.5 
psig.
psig.
psig.
psig.
psig.
psig.
psig.
psig.
psig.
psig.
psig. 
— Sea 1
— 1000
— 2000
— 3000
— 4000
— 5000
— 6000
— 7000
— 8000
— 9000 
Level
ft.
ft.
ft.
ft.
ft.
ft.
ft.
ft.
ft.
— 10000 ft. 
THERMOSTATIC SWITCH
(Universal and Chevy II All-Weather System)
Thermostatic switches used in Universal and All-
Weather systems differ only in the capillary tube sensing
unit.
The Chevy n All-Weather System thermostatic switch
has an air sensing capillary which is coiled and attached
to the front of the evaporator core with plastic plugs.
This type of unit is controlled by the temperature of the
air leaving the evaporator.
Universal systems make use of a thermostatic switch
with a fin sensing capillary or a self-supporting air sens-
ing capillary. This capillary controls the switch by
sensing the temperature of the metal fins or the air
leaving the fins.
Checking for Proper Operation
1.
 Install the gauge set and set up the vehicle as
described under Performance Test.
2.
 Movement of the temperature control knob should
result in a definite change in suction pressure and
cycling of the compressor clutch.
• If compressor continues to operate regardless of
the knob adjustment, it indicates that the points
CHEVROLET CHASSIS SERVICE MANUAL 

CORVETTE BODY 1B-53
13.
 Drill 1/2" hole at pilot hole locations.
14..
 Insert ferrules furnished for holes drilled in top
compartment lid. Crimp ferrule tabs. 
15.
 With aid of an assistant, place the hardtop onto the
vehicle and install attaching parts at all four loca-
tions.
 Lock latches at windshield header.
SPECIAL TOOLS
1.
 J9559 - Hood Spring
Tool 
Fig.
 115-Special Tools
2.
 J7797 - Door Handle
Clip Remover 
3. J8942 - Windshield Opening
Checking Blocks
CHEVROLET CHASSIS SERVICE MANUAL 

SECTION
 3
FRONT SUSPENSION
INDEX
Page
General Description
 . . . . 3-1
Maintenance and Adjustments
 3-3
Front Wheel Bearing Adjustment
 3-3
Front End Alignment
 3-5 .
Alignment Preliminary Steps ............
 3-5
Caster
 and
 Camber Adjustments
 . . 3-5
Chevelle, Caxnaro
 and
 Corvette
 3-5
Chevrolet and Chevy
 II 3-6
Steering Axis Inclination
 3-6
Toe-in Adjustment
 3-6
Cornering Wheel Relationship
 3-6
Riding Heigit
 and
 Coil Spring Sag
 3-7
Repair Procedures
 3-8
Front Brake Drum (Chevrolet, Camaro, Chevelle,
Chevy E)
 . . 3-8
Removal
 3-8
Installation
 3-8
Front Wheel Hub
 3-8
Replacement
 . . . . . 3-8
Replacement
 of
 Hub Wheel Bolts
 3-8
Front Wheel Bearings
 . . 3-8
Removal
 3-8
Inspection
 3-9
Repairs
 . . 3-9
Replacement
 of
 Bearing Cups
 3-9
Installation
 3-9
Steering Knuckle
 . . . 3-9
Removal
 3-9
Installation
 3-9
Shock Absorber
 3-10
Chevrolet, Chevelle, Camaro
 and
Corvette
 3-10
Removal
 , . 3-10
Installation
 3-10
Chevy
 It 3-11
Removal
 3-11
Installation
 3-11
Stabilizer
 Bar 3-11
Removal
 3-11
Installation
 3-11
Strut Rod
 3-11
Chevrolet and Chevy
 II 3-11
Removal
 3-11
Installation
 3-12
Front Coil Springs
 3-12
Chevrolet
 3-12
Removal
 3-12
Installation
 3-13
Chevelle
 and
 Camaro
 3-13
Removal
 3-13
Installation
 3-14
Chevy H
 3-14
Removal
 3-14
Spring Seat Disassembly and Assembly
 3-15
Installation
 3-15
Corvette
 3-15
Lower Control Arm Spherical Joint
 .' 3-16
Chevrolet, Chevelle, Camaro and
Corvette
 3-16
Inspection
 . 3-16
Chevrolet and Corvette
 3-16
Removal
 3-16
Installation
 3-16 
Page
Chevelle
 and
 Camaro
 3-17
Removal
 3-17
Installation
 . . . . 3-17
Chevy
 II 3-17
Inspection
 . 3-17
Removal
 3-17
Installation
 3-17
Lube Fittings
 3-18
Lower Control Arm
 . . . . 3-18
Chevrolet
 . 3-18
Removal
 3-18
Installation
 3-18
Chevelle and Camaro
 3-18
Removal
 3-18
Installation
 3-18
Chevy H
 3-18
Removal
 3-18
Installation
 3-19
Corvette
 3-19
Removal
 3-19
mstallation
 3-19
Lower Control Arm Bushings
 3-20
Chevrolet
 3-20
Removal
 3-20
Installation
 3-20
Chevelle and Camaro
 . 3-20
Removal
 3-20
Installation
 3-20
Chevy H
 3-21
Removal
 * 3-21
InstaEation
 3-21
Cross Shaft and/or Bushings
 . 3-21
Corvette
 3-21
Removal
 3-21
Installation
 3-21
Upper Control Arm Spherical Joint
 3-21
Chevrolet, Chevelle, Camaro and Corvette
 ..... 3-21
Inspection.
 3-21
Replacement
 3-21
Chevy
 II 3-21
Inspection
 3-21
Replacement
 3-21
Lube Fittings
 3-22
Upper Control Arm
 3-22
Chevrolet, Chevelle, Camaro
 and
 Corvette
 3-22
Removal
 3-22
Installation
 3-22
Chevy H
 3-22
Removal
 3-22
Installation
 3-23
Upper Control Arm Cross Shaft
and/or Bushings
 3-23
Chevrolet, Camaro and Chevelle
 3-23
Removal
 . 3-23
Installation
 3-23
Chevy H
 3-24
Removal
 3-24
Installation
 . . . 3-25
Corvette
 3-25
Removal
 3-25
Installation
 3-25
Special Tools
 3-26
Specifications
 ...'..'
 At rear of Book
GENERAL DESCRIPTION
The 1967 Chevrolet, Chevelle, Camaro, Chevy n and
Corvette front suspension systems are basically similar,
being of the
 S.L.A.
 (short-long arm) type with independent
coil springs. In the Chevrolet, Chevelle, Camaro and
Corvette the springs ride on the lower control arms; in 
the Chevy II the springs ride on the upper control arms.
Spherical joints connect the upper and lower arms to the
steering knuckle. Tapered roller wheel bearings are
used.
Camber angle is adjusted, on the Chevrolet and Chevy n
CHEVROLET CHASSIS SERVICE MANIM 

FRONT SUSPENSION 3-4
SHOCK ABSORBER
5PRING
UPPER
CONTROL
ARM
LOWER
CONTROL
ARM
STRUT ROD
STEERING KNUCKLE
Fig.
 4 - Front Suspension - Chevy
STEERING AXIS 
VERTICAL
CASTER ANGLE
CASTER 
WHEEL PLANE
VERTICAL PLANE
-CAMBER ANGLE
STEERING AXIS
INCLINATION
CAMBER
Fig.
 5 - Caster and Camber
CHEVROLET CHASSIS SERVICE MANUAL 

FRONT SUSPENSION 3-5
FRONT END ALIGNMENT
Front end alignment, that is alignment of the inter-
related steering components of the front suspension sys-
tem, must be correctly maintained to assure ease and
stability of steering and satisfactory tire life.
Alignment Preliminary Steps
Several different types of machines are available for
checking all the factors of front end alignment. The in-
structions furnished with each particular machine should
be followed. In all cases, however, checks should be
made with the vehicle level and at curb weight.
Since steering complaints are not always the result of
improper alignment a check should be made to see if any
of the following conditions exist. Any such conditions
should be corrected before proceeding further.
1.
 Steering gear loose or improperly adjusted.
2.
 Steering gear housing loose at frame.
3.
 Excessive wear or play in spherical joints or steer-
ing shaft coupling.
4.
 Tie rod or steering connections loose.
5.
 Improper front spring heights.
6. Unbalanced or underinflated tires.
7.
 Improperly adjusted wheel bearings.
8. Shock absorbers not operating properly.
Wheel alignment should always be made with the vehi-
cle rolled forward taking out any slack in the same man-
ner as when the vehicle is traveling forward.
Caster and Camber Adjustment
NOTE: Before adjusting caster and camber
angles, the front bumper should be raised and
quickly released to allow car to return to its
normal height.
Chevelle, Camaro and Corvette
Caster and camber adjustments are made by means of
shims inserted between the upper control arm inner sup-
port shaft and the support bracket attached to the frame
(fig. 6). Shims may be added, subtracted or transferred
to change the readings as follows: 
Fig.
 6 - Caster and Camber Adjustment - Chevelle
Typical of Corvette and Camaro
Caster - change shims at either the front or rear of
the shaft.
The addition of shims at the front bolt or removal
of shims at the rear bolt will decrease positive
caster. One shim (1/3 2") will change caster (ap-
prox.) 1/4°.
Camber - change shims at both the front and rear of
the shaft.
Adding an equal number of shims at both front and
rear of the support shaft will decrease positive cam-
ber. One shim (1/32") at each location will move
camber (approx.) 1/5° (Chevelle and Camaro); 1/6°
(Corvette).
TIGHTEN TO LOCK
ADJUSTMENT
Fig.
 7 - Caster and Camber Adjustment Points - Chevrolet
CHEVROLET CHASSIS SERVICE MANUAL 

FRONT SUSPENSION 3-10
CHEVROLET, CHEVELLE, CAMARO AND CORVETTE (TYPICAL) 
CHEVY H
Fig.
 14- Shock Absorber
NOTE:
 If necessary, tighten one more notch to
insert cotter pins.
3.
 Place brake backing plate and wheel cylinder in posi*-
tion on steering knuckle and insert anchor pin.
4.
 Place steering arm in position on back of steering
knuckle and insert two bolts through backing plate,
steering knuckle and steering arm. Install locknuts
and tighten. (See Specifications.)
5. Torque brake anchor pin (See Specifications).
6. Install brake shoes, except Corvette. (See Section 5.)
7. Install wheel hub, brake drum (or, on Corvette--
brake caliper and disc and hub assembly), wheel and
tire assembly over spindle.
8. Insert outer wheel bearing race and roller assembly,
washer and nut. Adjust front wheel bearing as shown
under Maintenance and Adjustments in this section.
Install new cotter pin, dust cap and hub cap.
9. Lower vehicle, recheck and readjust wheel alignment
where necessary.
SHOCK ABSORBER
Chevrolet, Chevelle, Comoro and Corvette (Fig. 14)
Removal
1.
 With an open end wrench hold the shock absorber
upper stem from turning, and then remove the upper
stem retaining nut, retainer and rubber grommet.
2.
 Remove the two bolts retaining the lower shock ab-
sorber pivot to the lower control arm and pull the
shock absorber assembly out from the bottom.
Installation
1.
 With the retainer and rubber grommet in place over
the upper stem, install the shock abosrber (fully ex- 
tended) up through the lower control arm and spring
so that the upper stem passes through the mounting
hole in the upper support arm.
2.
 Install the rubber grommet, retainer' and attaching
nut over the shock absorber upper stem.
3.
 With an open end wrench, hold the upper stem
from turning and tighten the retaining nut. (See
Specifications.)
4.
 Install the two bolts attaching the shock abosrber
lower pivot to the lower control arm and tighten.
(See Specifications.)
Fig.
 15 - Upper Control Arm Support Installed - Chevy II
CHEVROLET CHASSIS SERVICE MANUAL