1967 CHEVROLET CAMARO brake

ELECTRICAL-BODY AND CHASSIS 12-80

L.H. DOOR

JAMBSW

— —20Y
20QR
«
«t5§ COMPT LP

RADIO

HEAT .

CONTROL SW

HEAT CONTROL

LIGHT

CJG LIGHTER

14OR

20GY

20GY

•ONLY WIRES

PERTINENT

TO PRODUC-

TION OR NEU-

TRAL SAFETY

HAVE BEEN

SHOWN.

20T—

20P —

20P —

18DBL

20LBL

20T
12PPL

20LBL

20 T

14 OR

16BRN

20DBL

20 W

18LBI

18DBL

20LG

20DG
20 DG

20BRN

20OR

20PPL

14LBL

14OR

48LBL

18B

18DBL

R.H. DOOR

JAMBSW
•INSTRUMENT

CLUSTER

ILLUM <8)

BRAKE ALARM (33-39)

R.H. SIGLAMP(15)

GEN WARN. LAMP (25-39)

ILLUM (8)

ILLUM (8)

FUEL GAGE (39-30)

OIL PRESS. WARN. (31-39)

L.H. SIGLAMP (14) .

ENG TEMP WARN. LP (35-39)

ILLUM (8)

HIGH BEAM LAMP

LIGHT

SW "

W/S WIPER

SW

BODY HARNESS

Fig.
123 - Instrument Panel and Cluster - Camaro

CHEVROLET CHASSIS SERVICE MANUAL

BUMPERS 14-3

required to position the bumper at the correct

mounted height. ,

3.
Tighten all mounting bolts securely and connect li-
cense plate lamp wiring. On Caprice models, con-

nect back-up lamp wiring. Lower vehicle.

GENERAL DESCRIPTION-CHEVELLE

The new front bumper is of a one piece design with the

parking and turn signal lamp assemblies attached to each

outboard end of the bumper.
The rear bumper is also of a one piece design with

provisions for rear gas fill. The back-up lamp assem-

blies are attached near the center of the bumper.

SERVICE OPERATIONS

FRONT BUMPER ASSEMBLY

Removal

1.
Raise and support front of vehicle.

2.
Disconnect parking lamp wiring. -

Fig.
3 - Front Bumper Assembly - Chevelle

Disassembly

1.
Remove bolts attaching braces and brackets to

bumper.

2.
Remove bolts from each parking lamp assembly and

remove parking lamps from bumper.

Assembly

Attach both parking brake lamp assemblies to front

bumper and tighten bolts firmly. Assemble the front

bumper parts by following the disassembly procedure in

reverse order. Except for the parking lamp attachments,

install all bolts loosely; do not tighten any bolts until all

bolts are installed.

Installation

1.
Position the front bumper on the frame horns align-

ing holes in brackets and braces with those in the

frame.

2.
Loosely install bolts, lock washers, and nuts. Note

that eight sided adjustment washer (fig. 3) is placed

in the tab of each mounting bracket. Dial tjie adjust- .

ment washers in the tabs as required to position the

bumper at the correct mounted height.

3.
Tighten all mounting bolts securely, connect the

parking lamp wiring, and lower front of vehicle.
3.
Remove bolts retaining the bumper brackets and

braces to the frame.

4.
Remove bumper assembly from vehicle.

ADJUSTMENT

WASHER

Fig.
4-Rear Bumper Assembly - Chevelle

REAR BUMPER ASSEMBLY (Fig. 4)

Removal

1.
Raise rear end of vehicle.

2.
Disconnect rear license plate lamp and back-up lamp

wiring.

3.
Remove bolts, located behind license plate door, at-

taching face bar reinforcement to frame.

4.
Remove four bolts retaining bumper brackets and

braces to frame.

5. Remove bumper from vehicle.

Disassembly

1.
Remove license plate lamp and back-up lamps from

bumper.

2.
Remove brackets and braces at each end of bumper.

3.
Remove license plate door.

4.
Remove rivets attaching bracket at center of bumper.

Assembly

Attach license plate lamp and back-up lamp assemblies

to bumper; tighten bolts firmly. Assemble the bumper

parts by following the disassembly procedure in the re-

verse order. Except for the license plate lamp and back-

up lamp attachments, install all bolts loosely; do riot

CHEVROLET CHASSIS SERVICE MANUAL

ACCESSORIES 15-2

GENERAL DESCRIPTION

The Cruise Master is a speed control system which

employs engine manifold vacuum to power the throttle

Servo unit. The Servo moves the throttle when speed

adjustment is necessary by receiving a varying amount

of bleed air from the Regulator unit. The Regulator

varies the amount of bleed air through a valve system

which is linked to a speedometer-like mechanism. The

speedometer cable from the transmission drives the

Regulator, and a cable from the Regulator drives the

instrument panel speedometer. The. engagement of the
Regulator unit is controlled by an Engagement Switch

located at the end of the turn signal lever. Two brake

release switches are provided: an Electric Switch dis-

engages the Regulator unit and a Vacuum Switch de-

creases the vacuum in the Servo unit to quickly return

the throttle to idle position.

The operation of each unit of the system and the

operation of the entire system under various circum-

stances is described below. Figure 1 shows the location

of the system components within the vehicle-

COMPONENT OPERATION

ENGAGEMENT SWITCH

This switch, located within the turn signal knob, has

three positions. In the fully released position, the switch

passes current through resistance wire to effect a "hold

in" magnetic field in the Regulator solenoid. This cur-

rent is sufficient only to hold the solenoid in place once

it has been actuated by the "pull in" circuit. Depressing

the button partially allows current to flow to the Regu-

lator solenoid at full voltage which causes the solenoid

to pull in. Depressing the button fully opens the circuit

to both the resistance and standard solenoid feed wires

and the solenoid becomes de-activated.

During vehicle operation the three switch positions

have the following functions:

Released

a. System not engaged: No function of the system

will occur although a small current is flowing

through the solenoid via the resistance wire (at

vehicle speeds over 20 mph).

b.
System engaged: The small current flowing

through the resistance wire is holding the solenoid

in the engaged position.

^r-WIRE RELIEF LUG

1 ^-#2-BLUE WIRE

L'3.BLACK WIRE
X /-TURN SIGNAL LEVER

SWITCH—^
^SN

RETAINING RING-^ %^

BUTTON -^

Fig.
2 - Cruise Master Engagement Switch
Partially Depressed

Full voltage is applied to the solenoid (vehicle speed

over 20 mph) which sets the Regulator to maintain the

vehicle speed at the time of Regulator engagement.

Fully Depressed

No electricity flows to the solenoid and the Regulator

is inactive. This position is used by the driver when he

desires to raise or lower his controlled speed. He may

accelerate to his new speed, press the button fully (Regu-

lator releases previously set speed) and release the but-

ton. Upon releasing the button, it passes through the

partially depressed position and the solenoid is "pulled

in", then into released position which provides "hold in"-

current. The driver may also press the button fully with

no pressure on the accelerator pedal. In this case the

regulator releases control of the throttle which returns

to idle and the car slows. When the button is released

the solenoid is pulled in and held in respectively and the

regulator resumes speed control at the speed of the

vehicle during the moment of button release (at vehicle

speeds over 20 mph).

LOCK
NUT

ORIFICE
TUBE

AND
CONNECTOR

ASSEMBLY

AIR FILTER AND

SOLENOID HOUSING COVER

Fig. 3 - Regulator Unit

CHEVROLET CHASSIS SERVICE MANUAL

ACCESSORIES 15-3

CONTROLLED AIR SUPPLY

FROM REGULATOR
DIAPHRAGM

SPRING

METERING ROD

VARIABLE ORF1CE

ENGINE AAANIFOLD VACUUM

FROM REGULATOR VACUUM VALVE
BEAD CHAIN

VACUUM CHAMBER —*
MOUNTING SCREW

Fig.
4- Servo Unit

BRAKE RELEASE SWITCHES

Two brake release switches are employed in the Cruise

Master System. When the brake pedal is depressed, an

Electric Release Switch cuts off the voltage supplied to

the engagement switch, hence cuts off power to the Regu-

lator unit. The Regulator is then disengaged and requires

Engagement Switch operation to return it to operation.

A Vacuum Release Switch operates simultaneously with

the electric release switch whenever the brake pedal is

depressed. This switch opens a port to atmospheric

pressure which rapidly bleeds down the vacuum in the

Servo unit thereby returning the throttle to the idle

position.

SERVO UNIT

The Servo unit is a vacuum actuated, variable position

diaphragm assembly which operates the carburetor throt-

tle when the system is in operation (fig. 4). It is powered

by engine intake manifold vacuum and operates the throt-

tle linkage via a bead chain. The Servo has two ports on

the sealed side of the diaphragm housing: one is supplied

manifold vacuum, and the other is connected to a variable

air bleed in the Regulator Unit. The vacuum port is

located at the center of the unit and the air bleed port

is near the outer wall. When vacuum is applied to the
center port, atmospheric pressure moves the diaphragm

which pulls on the bead chain opening the carburetor

throttle. As the diaphragm moves, it positions a tapered

needle within an orifice in the vacuum port so that as the

diaphragm moves toward the port, the orifice becomes

smaller; and as it moves away from the port, the orifice

becomes larger.

The air bleed port serves to supply a variable quantity

of air to the diaphragm chamber which causes the dia-

phragm to attain a balanced state (between the force of

the atmospheric pressure to chamber pressure differ-

ential and the force of the diaphragm and throttle return

springs). In operation then, the following events occur:

Vacuum is applied to the center port and the diaphragm

moves toward the port. The tapered needle restricts

the vacuum port more and more as it moves into the

orifice. If no air was allowed to bleed into the chamber,

the diaphragm would move until it contacted the housing,

however, the Regulator meters bleed air into the chamber

and the diaphragm reaches a point at which the air is

bled out of the chamber through the vacuum port orifice

as fast as it enters the air bleed port. If the Regulator

begins to supply less bleed air, (vehicle speed decreas-

ing) the vacuum in the chamber increases and the dia-

phragm moves toward the vacuum port. In so doing, the

tapered needle closes the vacuum port orifice even more

CHEVROLET CHASSIS SERVICE MANUAL

ACCESSORIES 15-4

Fig. 5 - Servo Mounting

and the air bled into the chamber again equals the air

bled out. A balance occurs again with the diaphragm in

a new position. If the Regulator begins to supply more

bleed air, (vehicle speed increasing) the vacuum in the

chamber drops and the diaphragm moves away from the

vacuum port, withdrawing the tapered needle from the

orifice and enlarging it. Since the vacuum orifice is

now larger, the greater quantity of air being bled into

the chamber may be bled out by vacuum and a balance

again occurs with the diaphragm in a new position.

AIR

TO SERVO

VACUUM

TO SERVO
VACUUM

RELEASE

SWITCH

ELEaRIC

RELEASE

SWITCH

Fig.
6- Servo, Regulator and Hose
Fig. 7 - Release Switches and Brackets

REGULATOR

The Regulator is a device which has two primary

functions: First, it is a vacuum switch which, when en-

gaged by the driver, supplies engine manifold vacuum to

the Servo. Second, it meters a small variable quantity

of air to the Servo unit in order to change the carburetor

throttle opening to effect speed control. A secondary

function of the Regulator is to drive the speedometer.

Since the car speed is sensed by a speedometer-like

mechanism within the unit, the speedometer cable from

the transmission drives the Regulator which drives a

second cable (at a one to one ratio) to the speedometer.

The Regulator is electrically engaged and disengaged

through operation of the Engagement Switch and the

Electric Brake Release Switch. It has two sub-assem-

blies which make up the unit: one being the magnetic

speed sensing assembly and the other being the solenoid

actuated vacuum switch, air bleed and filter, and low

limit speed switch assembly (fig. 8 and 9).

Magnetic Speed Sensing Assembly

The speed sensing assembly operates in the same man-

ner as a speedometer unit except that instead of rotating

a needle through an angle proportional to the vehicle

speed, it rotates a rubber drum which is clutched to the

air bleed valve when the system is in operation. The

assembly is driven by the speedometer cable from the

transmission which turns a disk shaped ferrite magnet.

Facing the magnetic disk is the driven brass disk mounted

on a shaft with the rubber drum mounted on the same

shaft. A spiral hairspring connects the shaft to the

housing and allows it to rotate through an angle which is

proportional to car speed. If the car doubled its speed,

the shaft would rotate to twice its previous angle as may

be seen by noting the operation of a speedometer. The

CHEVROLET CHASSIS SERVICE MANUAL

ACCESSORIES 15-7

6. The car begins to descend a hill--car speed in-

creases slightly and the regulator movements oc-

curing above occur again except in reverse. The

rubber drum is turned further against spring tension

and the air bleed orifices are uncovered more. This

bleeds more air to the Servo reducing the vacuum in

the unit. The diaphragm moves away from the

vacuum port, closes the throttle slightly, and with-

draws the tapered needle from the vacuum orifice.

With the orifice enlarged, the increased vacuum

counteracts the increased air bleed and the dia-

phragm finds a balance again at a reduced throttle

opening.

7.
Driver accelerates by pressing accelerator pedal-

car speed increases and the system responds by

moving the diaphragm to decrease throttle opening.

Since a bead chain is used, the chain merely relaxes

and has no effect on throttle operation. After the

driver releases pressure from the pedal, the throttle

will close until car speed decreases to the pre-set

speed. At that point the Regulator bleeds less air

to the Servo which opens the throttle enough to

maintain the pre-set speed. The system returns to a

stable condition.

8. Driver desires higher controlled speed, presses ac-

celerator until new speed is reached, and depresses

Engagement Switch fully and releases button--speed

sensing assembly tries to turn in a direction that

would decrease the throttle opening until the driver

fully depresses the Engagement Switch. Then the

current is cut off to the solenoid which retracts; the

solenoid nose expands the "U" clip releasing its

grip on the rubber drum. The drum and disk as-

sembly then rotates to a new position because of the

higher car speed. When the solenoid retracts, it also

shuts off vacuum to the Servo and opens the vacuum

port to atmospheric pressure within the Regulator

thereby bleeding down the Servo toward idle throttle

position. As the driver releases the Engagement

Switch, the contacts cause "pull in" and "hold in" of

the solenoid respectively. The system is engaged to
maintain the car speed at the time of Engagement

Switch release.

9. Driver desires lower cruising speed, presses En-

gagement Switch fully, waits until car speed de-

creases to desired speed then releases Switch--when

the Engagement switch is fully depressed the sole-

noid is de-energized causing the vacuum switch to

bleed down the Servo to idle throttle position and the

"U"
clip of the idle bleed valve is released from the

rubber drum. The drum and disk assembly is free

to rotate to a position which corresponds to vehicle

speed as the car slows. When the driver releases

the Engagement Switch, the unit "pulls in" and "holds

in" in the normal manner. The air bleed valve is

clutched to, the rubber drum at the car speed during

switch release. Vacuum is again applied to the

Servo and throttle control is assumed by the Regu-

lator to maintain the car speed at the time of switch

release.

10.
With system in operation, driver applies brakes--

simultaneously the Vacuum Release and Electric

Release Switches operate. The Vacuum Switch

bleeds air into the Servo through the air bleed line

coming from the Regulator. The vacuum is reduced

in the Servo and the throttle returns to idle position.

The Electric Release Switch cuts off power to the

entire system and the solenoid is de-energized. If

the driver removes his foot from the brake pedal the

Electric Switch again feeds voltage to the Engage-

ment Switch and the Vacuum Switch seals the air

bleed line. If the vehicle speed is above 20 mph

when this occurs, reduced voltage will flow to the

solenoid through the 40 ohm wire which will not be

sufficient to "pull in" the unit. If vehicle speed is

below 20 mph no current will flow since the tang

on the rubber drum has opened the low limit switch

points in the Regulator. In either case, after de-

pressing the brake pedal, the system will not con-

trol car speed until the driver operates the engage-

ment switch above 20 mph.

SERVICE OPERATIONS

The components of the Cruise Master system are de-

signed to be replaced should they become inoperative.

The Regulator is calibrated in such a manner during

manufacturing that overhaul operations are impractical.

However, one adjustment may be made to the Regulator to

correct speed drop or increase at the time of

engagement.

BRAKE RELEASE SWITCHES

ELECTRIC

Service — An inoperative switch must be replaced.

Switch replacement is identical to standard brake lamp

switch replacement.

Adjustment- The brake switch plunger must clear the

pedal arm when the arm is moved 1/4 inch measured at

the switch (Figure 7).

VACUUM

Service
—
An inoperative (sticking, plugged, or leaking)

switch must be replaced. Switch replacement is similar
to brake switch replacement. Be certain that the hose to

the switch is connected firmly and is not cracked or

deteriorated.

Adjustment- The brake switch plunger must clear the

pedal arm when the arm is moved 5/16 inch measured at

the switch (Figure 7).

ENGAGEMENT SWITCH

Service

replacement.
The engagement is serviced only by

Removal

1.
Pry the engagement button out of the turn signal knob

with a small thin bladed screwdriver (Figure 2).

2.
With a small hook or long nosed pliers, remove the

switch retaining ring.

3.
.Pull switch outward utilizing the slack in the wiring

harness.

4.
With a small soldering iron, unsolder the wires and

resolder them to the correct terminals of the re-

placement switch.

CHEVROLET CHASSIS SERVICE MANUAL

ACCESSORIES
15-8

BROWN
BRAKE

SWITCH

+12V *

BLACK
CONNECTOR

AT FUSE BLOCK

CRUISE POSITION

BUTTON RELEASED

ENGAGE POSITION

BUTTON PARTIALLY DEPRESSED^ N. ENOAOi SWITCH

TRIM POSITION N. N. I

BUHON FULLY DEPRESSED. \ ^

BROWN

BLUE

ENGAGE SWITCH

CONFIGURATION

BLACK

BLUE

REGULATOR
- SOLENOID COIL

(5 a RESISTANCE)
9 BLACK

BLUE

REGULATOR

Fig.
10 - Wiring Diagram

Replacement

1.
Insert the switch into the turn signal knob, push the

retaining ring firmly against the switch, and push the

operating button onto the switch plunger. " .
SERVO

Service
—
H the Servo unit is found to be defective, re-

placement is required. Note the condition of the hoses

and replace any which are cracked or deteriorated.

CHEVROLET CHASSIS SERVICE MANUAL

ACCESSORIES 15-9

Adjustment- Adjust the bead chain so that it is as tight

as possible without holding the throttle open when the

carburetor is set at its lowest idle throttle position.

When connecting the bead chain (engine stopped) manually

set the fast idle cam at its lowest step and connect the

chain so that it does not hold the idle screw off the cam.

If the chain needs to be cut, cut it three beads beyond the

bead which pulls the linkage.

REGULATOR

Service - A defective regulator, that is one which is not

simply out of adjustment, must be replaced. During re-

placement, check the hoses which connect to the regulator

and replace any which are cracked or deteriorated.

Air Filter

The air filter located in the solenoid cover should be

cleaned and re-oiled at engine oil change intervals.

1.
Snap the solenoid cover off.

2.
Remove the filter and wash it in kerosene or mineral

spirits. Squeeze it dry and wet with SAE 10 engine

oil.
Squeeze out excess oil and reinstall into the

cover.

3.
Attach the cover with neoprene seal to the solenoid

housing. Be certain that the cover fits tightly to the

housing.

One regulator adjustment is possible: Engagement-

Cruising Speed Zeroing (to remove any difference be-

tween engagement and cruising speed).

NOTE:
No regulator adjustment should be

made, however, until the following items have

been checked or serviced:

1.
Bead chain properly adjusted.

2.
All hoses in good condition, properly attached, not

leaking, not pinched or kinked.

3.
Regulator air filter clean and properly oiled.

4.
Electric and vacuum release switches properly

adjusted.

Engagement—Cruising Speed Zeroing

If the cruising speed is lower than the engagement

speed, loosen the orifice tube locknut and turn the tube

outward; if higher, turn the tube inward. Each 1/8 turn

will alter the engagement-cruising speed difference one

mph. Tighten the locknut after adjustment and check the

system operation at 50 mph.

ELECTRICAL SYSTEM CHECK OUT

1.
Check fuse and connector.

2.
Check electric brake switch as follows: Unplug con-

nector at brake switch. Connect ohmmeter at points

A and B on brake switch. The ohmmeter must indi-

cate infinity when the brake pedal is depressed and

continuity when pedal is released. The cruise re-

lease brake switch (electric) is adjusted as is the

standard stop light brake switch. Replace electric

brake switch if needed.

3.
Check engagement switch and connecting wiring as
follows: Unplug push button control connector

(brown, blue, black) at electrical wiring harness con-

nector and perform the following tests. (See Fig-

ure 10)

Test #1
—
Connect ohmmeter between terminal #1 (brown

wire) and terminal #2 (blue wire). Continuity shall be

maintained until switch is depressed all the way in.

Test #2
—
Connect ohmmeter between terminal #1 (brown

wire) and terminal #3 (black). No continuity shall be

shown; however, when the button is depressed halfway,

continuity shall be indicated. When the button is pressed

all the way down, no continuity shall be shown.

Test #3 — Connect ohmmeter between terminal #2 (blue

wire) and terminal #3 (black). Button released, no con-

tinuity; however, when the button is depressed partially

and fully, continuity shall be shown.

4.
Check regulator solenoid coil, low-speed switch, and

wiring harness as follows:

a. Disconnect engagement switch wire harness con-

nector from the main wire harness connector

(brown, blue, and black wires). Connect ohm-

meter
'
between point C (blue wire in main wire

harness) and ground. (Make sure the regulator is

well grounded to chassis.) The ohmmeter should

read 45 ohms ± 2 ohms. If a resistance of

greater value is shown, then disconnect the con-

nector from the regulator and measure the re-

sistance of the blue wire from point C to D. It

should measure 40 ohms. Check the resistance

from point E (vertical bar of terminal forming T)

to ground. It should measure 5 ohms ± 1/4 ohm.

Replace either the wiring harness or solenoid as

needed if greater values are indicated. The black

harness wiring from point F to G should also be

checked for continuity.

ENGAGEMENT SWITCH TEST

BUTTON POSITION

Cruise (released)

Engage (partially depressed)

Trim (fully depressed)
TERMINALS

1 TO 2

closed

Closed

open
1 TO 3

open

closed

open
2 TO 3

open

closed

closed

SERVO AND VACUUM SYSTEM CHECK OUT

To determine the condition of the diaphragm, remove

hoses from power unit and apply 14 inches of vacuum to

either vacuum tube opening (seal the other opening) and

hold in for one minute. The vacuum shall not leak down

more than 5 inches of vacuum in one minute. If leakage

is detected, replace servo. To utilize engine as a vac-

uum source, proceed as follows:

1.
DISCONNECT SERVO $EAD CHAIN and hoses from

servo and connect engine vacuum directly to vacuum

servo fitting (fitting in middle of servo). Seal the

servo unit opening.

2.
Note position of servo diaphragm.

3.
Start engine - the diaphragm should pull in.

4.
Clamp off engine vacuum supply line and check for

leakage. '

The cruise release brake switch (vacuum) and connecting

hoses can likewise be checked using a vacuum pump.

CHEVROLET CHASSIS SERVICE MANUAL