WHEELS AND TIRES 10-4
the road and it slips, grinding off the tread on the inside
half of the tire at an excessive rate. This type of tire
shows much the same appearance of tread wear as tire
wear caused by negative camber.
Second, the transfer of weight may also over-load the
outside tires so much that they are laterally distorted
resulting in excessive wear on the outside half of the
tire producing a type of wear like that caused by ex-
cessive positive camber.
Cornering wear can be most easily distinguished from
abnormal camber wear by the rounding of the outside
shoulder or edge of the tire and by the roughening of the
tread surface which denotes abrasion.
Cornering wear often produces a fin or raised portion
along the inside edge of each row in the tread pattern.
In some cases this fin is almost as pronounced as a
toe-in fin, and in others, it tapers into a row of tread
blocks to such an extent that the tire has a definite step
wear appearance.
The only remedy for cornering wear is proper in-
struction of owners.
Fig.
5 - Tire Rotatidh
Rotation
To minimize the possibility of tire noise and to equal-
ize tire wear, it is recommended that tires be inter-
changed every 6000 miles as shown in Figure 5 or more
frequently in the case of extremely heavy wear.
NOTE:
Rotate Corvette tires at 4000 miles or
sooner.
Interchanging tires will effectively prevent undue wear
on any particular tire. II tire interchanging is followed
as recommended above, all tires will have the same
number of miles in each wheel position at the end of the
fourth change. When interchanging tires, inspect for
signs of abnormal wear, bulging, etc., stones, glass, and
nails should be removed before reinstallation.
Noise
Noise caused by the normal action of tire treads on
various road surfaces is often confused with rear axle
gears or other noises in the car.
The determination of whether tires are causing the
noise complained of is relatively simple. The car should
be driven at various speeds and note taken of part
throttle, and sudden acceleration and deceleration. Axle
and exhaust noises show definite variations under these
conditions, while tire noise will remain constant. Tire
noise is, however, most pronounced at speeds of approx-
imately twenty or thirty miles per hour.
The tires may be further checked by driving the ear
over smooth pavement with the tires at normal pressure
and again over the same stretch of pavement when the
tires have been inflated to fifty pounds pressure. Reduce
the tires to normal pressure one at a time to determine
the faulty tire or tires. This high inflation pressure
should immediately be reduced to normal after test. If
the noise for which the test is being made is caused by
tires,.
it will noticeably decrease when the tire pressure
is increased, whereas axle noise should show no change
in volume.
If, on inspection, the tires on the front wheels are
found to be creating most of the noise the alignment of
the front wheels should be checked. Excessive tire noise
usually results from lower than recommended tire pres-
sure, incorrect alignment, uneven tire wear, or defective
(thumper) tire.
Cleaning
A great deal of ordinary road dirt which collects on
white sidewall tires may be sponged off with clear water
or a mild soap solution.
A good brand of whitewall tire cleaner, however, is
a quicker and more effective cleaner for removing dirt
and stains from whitewall tires and in many cases it
will remove stains and discoloration that the simpler
method of soap and water will not remove.
Under no circumstances should gasoline, kerosene or
any cleaning fluid containing a solvent derived from oil
be used to clean whitewall tires. Oil in any form is
detrimental to tire rubber and a cleaner with an oil base
will discolor or injure whitewall tires.
Change (W/Wheels)
To change the road wheels using the jack that comes
with the car, observe the following procedure:
1.
Set hand brake and block front wheels if rear wheel
is being changed.
2.
Remove hub cap or wheel disc and break wheel
mounting nuts loose.
3.
Place the jack as directed tinder, General Informa-
tion,
Section 0 and raise car until wheel clears
ground.
4.
Remove wheel mounting nuts and remove wheel from
hub or drum.
5. To replace road wheel, reverse the above instrue-
. tions. Proper torque on nuts is 55-75 ft. lbs.
torque (70-85 ft. lbs. for Corvette aluminum wheel
nuts).
CAUTION: On models equipped with discs, in-
dex the pilot hole in the disc on the valve stem.
(To insure that the anti-rotation notches in wheel
disc register on lugs in wheel rim.)
CHEVROLET CHASSIS SERVICE MANUAL
WHEELS AND TIRES
10-6
lifted on the rim to force the top tire bead
against the top rim flange. The weight of the
tire will seat the bottom bead.
Repair
When a tire loses all or most of its air pressure,
particularly when driving at high legal speeds on today1 s
super-highways, recommended procedure is to remove it
from the wheel for complete inspection to be sure no
tire damage has occurred. Punctured tires should be
removed from the wheel and permanently repaired from
the inside.
Externally applied plug type repairs should be con-?
sidered temporary and the tire should be permanently
repaired as soon as possible.
Hot Patch Method
It is essential to thoroughly clean and remove all
foreign matter from the hole left by the puncturing-object
without enlarging the injury and then follow the manu-
facturer's instructions for vulcanizing the patch.
Rubber Plug Methods
There are several types of rubber plugs--some are
inserted from the inside of the tire; others are inserted
from the outside of the tire without demounting the tire
from the rim.
When using the plug method be sure to clean and
lubricate the hole with repair cement before inserting
the plug. Your tire supplier has available complete kits
containing materials, tools and detailed instructions for
making repairs with plugs. Follow instructions in the kit
you use.
Cold Patch Method
(Self Vulcanizing Type)
In this method it is essential to thoroughly clean and
remove all foreign matter from the hole left by the
puncturing object without enlarging the injury; also on
the inside of the tire, buff an area large enough for the
patch. Follow the manufacturer1 s instructions for appli-
cation of the special cement and self-vulcanizing cold
patch.
Pressure Gun Method
Several types of pressure guns are available. Consult
your tire supplier for materials and instructions.
Tire Installation Safety Precautions
When tires are mounted on dirty or corroded rims, or
when they are not properly centered on rims, the tire
bead may "bind" on the rim, and refuse to seat. Allowing
pressure to continue to build up within the assembly in
an attempt to seat the tire bead is a DANGEROUS PRAC-
TICE which can result in a broken tire bead, and serious
injury to the serviceman.
1.
Make sure that rim flanges and bead ledge (espe-
cially hump and radius) areas are smooth and clean.
Remove any oxidized rubber, dried soap solution,
rust, heavy paint, etc. with a wire brush, or, in ex-
treme cases, a file.
2.
Lubricate tire beads, rim flanges, and bead ledge
areas with a liberal amount of thin vegetable oil
soap solution, or approved rubber lubricant,
3.
Insure that air pressure build-up during the bead
seating process is not allowed to exceed 40 pounds
pressure. If beads have not seated by the time pres-
sure reaches 40 pounds, assembly should be deflated,
re-positioned on rim, re-lubricated and re-inflated.
4.
Make sure valve core is inserted in valve stem
prior to inflating.
5.
Use an extension gauge with clip on chuck so air
pressure build-up can be closely watched and so
that you can stand well back from the assembly
during the bead seating process.
WHEELS
Valve Assembly
Replace
NOTE: Always use new valve assembly when
replacing.
1.
Cut or drive old valve assembly out of rim.
2.
Clean valve hole and surrounding area on inside of
flange with steel wool.
Fig. 6 - Installing Valve
Fig. 7 - Rim Inspection
CHEVROLET CHASSIS SERVICE MANUAL
SECTION 12
ELECTRICAL-BODY AND CHASSIS
CONTENTS
OF
THIS
SECTION
Page
Page
System 12-1
Instruments and Gauges 12-21
Directional Signal 12r40
Windshield Wipers and Washers 12-44
Wiring Diagrams 12-56
Special Tools 12-60
LIGHTING SYSTEM
INDEX
Page
General Description
!2-i
Maintenance and Adjustments
•.................. 12-2
Headlamp Adjustment......................
12-3
Headlamp Panel Travel Adjustment.
12-5
Service Operations.
. . .. 12-5
Front Lighting
12-5
Headlamp
. 12_5
Parking Lamp
12-5
Fender Lamp
. 12_^
Headlamp Panel
12-8
Headlamp Panel Motor
^2-9
Rear Lighting
l2-10
Tail, Stop and Directional Lamps
12-10
Page
Backing Lamps
12-14
License Plate Lamp
12-14
Automatic Transmission Quadrant Lamp
12-14
Seat Separator Console Lamps
. 12-15
Lighting Switch
. . 12-15
Wiper Switch.
12-15
Stoplight Switch
12-15
Dimmer Switch
12-15
Backing Lamp Switches
12-15
Neutral Safety Switches
12-17
Parking Brake Alarm Switch
................. 12-19
Instrument Panel Compartment Lamp/Switch
12-19
Cirgarette Lighter
12-19
GENERAL DESCRIPTION
.
The lighting system includes: the main lighting switch,
stop light, dimmer, and backing lamp switches, head-
lamps, parking lamps, stop, tail and directional lamps,
instrument illumination and indicator lamps, and the
necessary wiring to complete the various circuits. A
fuse panel provides convenient power take offs and fuse
clips for the appropriate circuits (fig. 1).
Chevrolet and Chevelle headlamp installation is all
new in that the headlamps are located in the radiator
support with adjusting screws and springs. Eliminating
the need for having separate headlamp housings. Chev-
rolet and Chevelle headlamp retainers and springs are
interchangeable.
Chevy n headlamp housings are new because of revised
front end styling and Corvette front end lighting is basi-
cally carryover.
Front fender lamps have been added as an option for
Chevrolet models and as standard equipment on Caprice
series.
Camaro models use single headlamps and the Rally
Sport model headlamps are covered by a retractable
section of the grille when lamps are not used. The sec-
tion of the grille covering the headlamps folds back when
lights are required; the headlamps are stationary. The
covering is retracted by a small electric motor mounted
to the headlamp housing. The headlamps are automat-
ically uncovered when the headlight switch is pulled "ON"
for illumination. If at any time the electrical circuit
becomes inoperative, the lamps can be uncovered manu-
ally. The ignition switch must be
"ON"
in order to close
the headlamp doors.
Parking lamp for Chevelle and Chevrolet models are
new due to revised front end sheet metal and bumper
styling. Parking lamps are located in the bumper on
Chevrolet, Chevelle and Chevy n models
Camaro parking lamps are located in the radiator
grille except for the Rally Sport models on which the
parking lamps are in the valance panel. For styling
reasons, the lens is white and an amber glass bulb is
used. All Camaro parking lamps require a separate
ground wire to assure a good ground contact because of
the plastic grille and painted contact surfaces.
The Chevrolet tail, stop, and directional lamps are in
one housing with a three section lens design on Impala
and Caprice sedans. The center lens for Impala series
is the back-up lamp. The center lens on the Caprice is
a tail lamp with the back-up lamps being located in the
rear bumper. Chevrolet station wagons have three indi-
vidual housings with three lenses, the center lamp being
the back-up. Biscayne and Bel-Air sedans have a single
housing and lens for tail, stop, and directional lamp with
a similarly constructed back-up lamp inboard and adja-
cent to it.
Chevelle tail, stop, and directional lamps are a single
lens design that follows through with the rear fender
styling. The back-up lamp is located in r.ear bumper.
Camaro models except Rally Sport have tail lamps
with integral back-up lamps mounted inboard of the rear
fenders between the trunk opening and bumper. The
Rally Sport model has dual tail lamps in the rear housing
and valance mounted back-up lamps.
Corvette, Chevy n, and Corvair tail and directional
signal lights are carryover. The Corvette has new back-
up lamps center mounted above the license plate opening.
CHEVROLET CHASSIS SERVICE
ELECTRICAL-BODY AND CHASSIS 12-2
FJg.
1 - Fuse Panel Assembly
All power window and tailgate circuits require the igni-
tion switch to be "ON" to open or close the windows un-
like past model designs which were operated independ-
ently of the ignition switch.
The windshield wiper and washer switch is new in that
washer button in the center of the knob has been deleted
and its function will be accomplished by pushing the knob.
A set screw is used to retain the knob to the shaft.
In addition to fuses, the wiring harness incorporates
fusible links to protect the wiring. Links are used rather
than a fuse in wiring circuits that are not normally fused,
such as the ignition circuit. Fusible links in the Chevro-
let wiring are four gauge sizes smaller than the cable it
is designed to protect. The links are marked on the
insulation with wire gauge size because of the heavy insu-
lation which makes the link appear a heavier gauge than it
actually is.
Engine compartment wiring harness incorporate sev-
eral fusible links. Each link is identified with its gauge
size.
A fusible link is a length of special wire (normally
four wire gauges smaller than the circuit it is protecting)
used in wiring circuits that are not normally fused, such
as the ignition circuit. The same size wire with a spe-
cial hypalon insulation must be used when replacing a
fusible link.
The links are:
1.
The pigtail lead at the battery positive cable (except
Corvette) is a 14 gauge, brown fusible link protecting
the 10 gange battery charging circuit. This wire is
an integral part of the battery cable assembly and
servicing requires replacing the complete battery
cable assembly. On Corvette models this link is
installed as a molded splice at the solenoid "Bat"
terminal and servicing requires splicing in a new
link.
2.
A 16 gauge black fusible link is located at horn relay
to protect all unfused wiring of 12 gauge or larger.
It is a serviceable piece with an in-line connector
and is not integral with the wiring harness.
3.
The generator warning light and field circuitry (16
gauge wire) is protected by a fusible link (20 gauge
orange wire) used in the "battery feed to voltage
regulator #3 terminal" wire. The link is installed
as a molded splice in the generator and forward lamp
harness and is serviced by splicing in a new 20 gauge
wire as required.
4.
The ammeter circuit on all models is protected by
two orange, 20 gauge wire fusible links installed as
molded splices in the circuit at the junction block or
the solenoid "Bat" terminal (Corvette only) and at the
horn relay. Each link is serviced by splicing in a
new 20 gauge wire as required.
The wiring harnesses use a standarized. color code
common to all Chevrolet vehicles. Under the color code,
the color of the wire designates a particular circuit. The
harness title indicates the type of harness, single of mul-
tiple wire, and also describe the location of the harness.
The body harness is a flat, solid wire assembly and is
routed through the vehicle near the center of the body.
Composite wiring diagrams (figs. 104 thru 124) are in-
cluded at the end of this section.
MAINTENANCE AND ADJUSTMENTS
Maintenance of the lighting units and wiring system
consists of an occasional check to see that all wiring
connections are tight and clean, that the lighting units are
tightly mounted to provide good ground and that the head-
lamps are properly adjusted. Loose or corroded con-
nections may cause a discharged battery, difficult start-
ing, dim lights, and possible damage to generator and
regulator. Wire harnesses must be replaced if insulation
becomes burned, cracked, or deteriorated. Whenever it
is necessary to splice a wire or repair one that is bro-
ken, always use solder to bond the splice. Always use
rosin flux solder on electrical connections. Use insulat-
ing tape to cover all splices or bare wires.
When replacing wires, it is important that the correct
size be used. Never replace a wire with one of a smaller
size.
Each harness and wire must be held securely in place
by clips or other holding devices to prevent chafing or
CHEVROLET CHASSIS SERVICE MANUAL
ELECTRICAL-BODY AND CHASSIS 12-16
BACK-UP LAMP CONN.
CONSOLE CTSY
LAMP CONN
CLOCK CONN
NEUTRAL SAFETY SWITCH
Fig.
22 - AutoTrans — Seat- Separator Wiring — Chevelle
TAIL
PANEL Ll<
J
TAIL
LIGHTS ^^g
9
""TUtflll -^ ""
DOME
LIGHT
r
•I
m
/
LIGHTS
FUSE HEADLIGHTS
9R
jl PARKING LIGHTS
*^ R ATTPRY
Fig.
23 - Light Switch Terminal Connections
Fig.
24 - Light Switch and Cigarette
Lighter Installation
CHEVROLET CHASSIS SERVICE MANUAL
Fig.
48 - Instrument Panel Wiring Hamess
1.
To Instrument Panel
Compartment light
2.
Heater Control Bulb
3. To Heater Switch
4.
To Directional Signal Flasher
5.
6.
7.
a
To Heater Resistor
To Blower Motor
Connector
To Cigarette Lighter
To Ignition Switch
9.
10.
11.
12.
To Wiper Switch
To Light Switch
To Fisher Body Connector
To Directional Signal
Connector
13.
To Stop Lamp Switch
14.
To Backing Lamp
15.
Fuse Panel
16.
To Dimmer Switch
ELECTRICAL-BODY AND CHASSIS 12-35
SERVICE OPERATIONS
INSTRUMENT CLUSTER
REMOVAL AND INSTALLATION (Fig. 49)
1.
Remove mast jacket assembly. Refer to Section 9
for removal procedures.
2.
Disconnect tachometer drive cable at distributor.
3.
Disconnect the headlamp panel control switch from
instrument cluster.
4.
Remove lighting switch as outlined in this section.
10 10-A 1112 13
14
15 16 17 18 19
Fig.
49- Instrument Cluster Connections
1.
Cluster Illuminating
Bulbs
2.
Direction Signal Indicator
Bulb L.H.
3. Direction Signal Indicator
BulbR.H.
4.
Headlamp Actuating Motor
Indicator
5. Headlamp Hi Beam
Indicator
6. Parking Brake Alarm
Indicator
7. Ground Lead Attaching
Point
8. Temperature Indicator
"1"
Terminal
9.
10.
10A.
11.
12.
13.
14.
]5.
16.
17.
18.
19.
20.
21.
Temperature Indicator "S"
Terminal
Ignition Switch Receptacle
ignition Switch Illuminating
Bulb
Oil Pressure Indicator
Tachometer
Lighter Receptacle
Trip Odometer
Wiper Switch Receptacle
Speedometer
Ammeter "Gen" Terminal
Ammeter "Battery" Terminal
Lighting Switch Receptacle
Fuel Gauge
"1"
Terminal
Fuel Gauge "S" Terminal
5. Remove the ignition switch. Refer to Section 6Y
for removal procedure. Then disconnect ignition
switch lamp support at instrument panel.
6. Disconnect oil pressure line at oil pressure gauge
then remove the lead wires from ammeter, wiper
switch and cigarette lighter. Disconnect trip odom-
eter at mast jacket support.
7. Remove the instrument cluster-to-dash retaining
screws and pull cluster assembly slightly forward
to obtain clearance for removal of speedometer
cable, tachometer cable, cluster ground wire, fuel
gauge lead wires and remaining indicator and cluster
illuminating lamps.
8. To install cluster in dash panel, reverse removal
procedure.
FUEL GAUGE
The gasoline fuel gauge circuit consists of an electri-
cal indicator in the instrument cluster and a float-
controlled rheostat in the fuel tank.
Since the fuel gauge consists of two remotely located
units and connecting wires, it is sometimes difficult to
determine which unit is at fault when the gauge fails to
operate properly. Cluster removal is necessary to re-
place the fuel gauge.
NOTE:
Be sure to check gas gauge fuse in fuse
panel before attempting to trouble shoot for
inoperative gauge or tank sending unit.
SPEEDOMETER AND/OR TACHOMETER
Removal and Installation
Cluster must be removed from vehicle to service
speedometer head assembly (see Cluster Removal pro-
cedure)
.
With cluster removed from vehicle:
1.
Remove five screws securing cluster back panel to
cluster assembly; separate the parts carefully.
CAUTION: Care must be used to avoid marring
instrument cluster face.
2.
Remove two screws securing speedometer or ta-
chometer head to cluster back panel; carefully re-
move speedometer or tachometer head.
NOTE:
Servicing of speedometer or tachom-
eter head should be performed by an authorized
AC service station.
3.
Reverse above procedure to install speedometer.
Cable Replacement or Lubrication
1.
Disconnect the. cable from the speedometer or ta-
chometer head. Remove the old cable by pulling it
out from speedometer end of conduit.
NOTE:
If old cable is broken it may be nec-
essary to remove lower piece from transmission
or distributor end of conduit as applicable.
2.
Lubricate the lower 3/4 of cable with
AC
speedom-
eter cable lubricant and push the cable into the con-
duit. Connect the upper end to the speedometer or
tachometer head and road test vehicle for proper
operation.
TEMPERATURE GAUGE
The temperature indicator requires very little service
other than testing for malfunctioning and replacing de-
fective units. Cluster must be removed to service tem-
perature gauge.
Do not attempt to repair either the engine unit or the
gauge. When installing new engine unit, do not use
thread compound on unit threads, as this will increase
electrical resistance of unit and cause faulty reading
on gauge.
AMMETER OR OIL PRESSURE GAUGE
The ammeter or oil pressure gauge requires very
little attention other than keeping ammeter terminals
clean and tight. If the oil pressure control line should
become restricted it should be blown out or replaced.
Cluster must be removed to service these gauges.
HftVKI MANUAL
17-
VIEW A
Fig.
53 - Instrument Panel Wiring Harness
1.
To Glove Box Light
2.
To Heater Control
3. Heater Control Lamp
4. To Cigarette Lighter
5. To Ignition Switch
6. To Instrument Cluster
7. To Wiper Switch
8. To Light Switch
9.
To Directional Signal Switch
10.
To Stop Lamp Switch
11.
To Backing Lamp Switch
12.
Fuse Panel
13.
To Dimmer Switch
14.
To Fisher Body Connector
15.
To Directional Signal Flasher
16.
To Heater Resistor
17.
Directional Signal Flasher