1967 CHEVROLET CAMARO tire pressure

STEERING 9-35

Fig.
66—Power Steering Diagnosis

shown in Figure 66. Gauge must be between shut-

off valve and pump. Open shut-off valve,

b.
Remove filler cap from pump reservoir and check

fluid level. Fill pump reservoir to full mark on

dip stick. Start engine and, holding steering

wheel against stop, check connections at Tool

J-5176 for leakage. Bleed system as outlined
under Maintenance and Adjustments. Insert ther-

mometer (Tool J-5421) in reservoir filler open-

ing. Move steering wheel from stop to stop

several times until thermometer indicates that

hydraulic fluid in reservoir has reached tempera-

ture of 150° to 170°F.

CAUTION: To prevent scrubbing flat spots on

tires,
do not turn steering wheel more than five

times without rolling car to change tire-to-floor

contact area.

c. Hold steering wheel against a stop momentarily

and read pressure gauge. If the maximum pres-

sure is below specifications, a faulty hydraulic

circuit is indicated. To determine which part is

faulty, proceed with test number two.

Test Number Two—Oil Circuit Closed

a. Slowly turn shut-off valve on J-5176 to closed

position and read pressure indicated on gauge.

Quickly reopen valve to avoid pump damage, if

indicated pressure is less than specification,

pump output is below requirement and pump may

be considered faulty. If pressure indicated is

within specifications, it may be safely assumed

that the external hoses, connections, valve and

adapter or steering gear is at fault.

NOTE:
If pump proves faulty in test number

two,
test should be repeated after pump is re-

paired and installed in vehicle. This will provide

a means of checking the repairs made to the

pump and the condition of the steering gear or

valve and adapter which may also be faulty.

COMPONENT REPLACEMENT AND REPAIRS

POWER STEERING PUMP

Removal (Fig. 67)

1.
Disconnect hoses at pump. When hoses are discon-

nected, secure ends in raised position to prevent

drainage of oil. Cap or tape the ends of the hoses to

prevent entrance of dirt.

NOTE:
Chevelle with 396 engine uses a remote

reservoir. It is necessary to disconnect the

reservoir to pump hose before removing the

pump.
Hold a 1 qt. container under the reservoir

when the hose is removed to catch the fluid.

2.
Install two caps at pump fittings to prevent drainage

of oil from pump.

3.
Remove pump belt.

4.
On Corvette with 427 engine, loosen alternator ad-

justment and remove pump to alternator belt.

5. Remove pump from attaching parts and remove pump

from vehicle.

NOTE:
On Chevrolet and Chevy II equipped with

283 and 327 engine it may be necessary to re-

move pump brace.

6. Remove drive pulley attaching nut.

7. Remove pulley from shaft with Tool J-21239 (for

stamped pulleys) or Tool J-8433-1 with J-8433-2
adapter (for cast iron pulleys). Do not hammer

pulley off shaft as this will damage the pump.

Fig.
67—Power Steering Pump Mounting

CHEVROLET CHASSIS SERVICE MANUAL

SECTION 10

WHEELS AND TIRES

INDEX

Page

General Description
10-1

Maintenance
and
Adjustments
.............. 10—1

Tires
10-1

Pressures . 10-1

Inspection 10-1

Wear 10-1

Rotation 10-4

Noise 10-4

Cleaning 10-4

Change (W/Wheels) 10-4

Wheels 10-5

Static Balancing (w/Tire) 10-5
Page

Dynamic Balancing (w/Tire) . 10-5

Run Out (w/o Tire) 10-5

Cleaning 10-5

Service Operations 10-5

Tires 10-5

Removal 10-5

Installation 10-5

Repair 10^6

Wheels . 10-6

Valve Assembly 10-6

Repair (Rim) 10-7

GENERAL DESCRIPTION

WHEELS

Chevrolet, Chevelle, Camaro, Chevy n, and Corvette

are base equipped with welded steel wheels. Five studs

with nuts fasten each wheel to the front hub or rear axle

flange. Disc brake equipped vehicles (except Chevrolet

and Corvette) require special 14 inch diameter wheels

with a revised design for clearance, Chevrolet disc brake

equipped vehicles have 15 in. diameter wheels as do all

Corvettes.

Chevrolet station wagons, Chevelle Super Sport 396,

Corvette and Camaro Super Sport 350 are base equipped

with 6 in. width wheels. All other vehicles have 5 in.

width wheels, except Chevy n 100, 300 and 500 Series

Sedans, which have 4 in. width wheels.

Do not install 6 inch width wheels or snow chains on

Chevrolets equipped with rear fender skirts.

TIRES

The factory installed tires on Chevrolet passenger

cars are selected to provide the best all around tire

performance for all normal operation. They are de-

signed to operate satisfactorily with loads up to and in-

cluding the specified full rated load capacity of the
automobile when inflated as recommended in the Vehicle

Capacity Rating and Recommended Tire Inflation Pres-

sures Table (see Specifications).

Optional Oversize and 8-Ply Rating Tires

{Chevrolet and Chevelle Only)

Oversize or 8-ply rating tires are not necessary on

passenger cars for normal requirements. However, an

extra margin of tire service is available when these

options are used at loads up to and including full rated

load.

Optional oversize 4-ply rating and/or 8-ply rating

tires are available on models as indicated in the Tire

Usage Chart (see Specifications). On some models (ex-

ample—Station Wagon), space limitations do not permit

the use of a larger size tire; hence, the 8-ply rating

tire is an available option.

In either case, these tires are applicable to extended

operation at or near full rated load or for trailer towing

when an extra margin of tire service is desired. How-

ever, use of a larger tire or an 8-ply rating tire should

not be construed as permitting an increase in the full

rated vehicle load (see Specifications).

MAINTENANCE AND ADJUSTMENTS

TIRES

Inflation Pressures

To ensure the proper tire inflation pressure for the

owners particular requirements follow the recommenda-

tions in the Vehicle Capacity Rating and Recommended

Tire Inflation Pressures Table (seeSpecifications). Keep

tires properly inflated, and check inflation pressures

periodically. This will ensure the best tire life and riding

comfort, over the full range of driving conditions.
Inspection

Every few thousand miles and at each lubrication, tires

should be checked for sharp objects or stones in the

tread. H tire is punctured, it should be repaired using

one of several repair kits available through tire manu-

facturers1 outlets.

Wear

Misalignment

This is wear due to excessive toe-in or toe-out. In

CHEVROLET CHASSIS SERVICE MANUAL

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

ELECTRICAL-BODY AND CHASSIS 12-3

Fig.
2 - T-3 Safety Aimer

wearing away the insulation due to vibration.

By referring to the wiring diagrams, circuits may be

tested for continuous circuit or shorts with a conventional

test lamp or low reading volt meter.

HEADLAMP ADJUSTMENT-

T-3 HEADLAMPS

CAUTION: Check and tighten radiator support

grille retaining bolts prior to attempting head-

lamp aiming. Distorted grille or supports in

this area will hinder proper aiming of head-

lamps. On Corvette models make sure head-

lamp panel is adjusted properly - refer to

"Headlamp Panel Travel Adjustment".

When aiming headlamps, vehicle should be filled to ca-

pacity with gas, oil, and water but no load. Tires should

be uniformly inflated to recommended pressure.

the T-3 Safety Aimer-Type B (fig. 2), is used for the

headlamp aiming description that follows. An adapter is

required with the Type B T-3 Aimer when adjusting the 7

inch headlamp used on the Chevy n vehicle.

1.
Drive vehicle onto selected aiming area. Bounce

vehicle several times and allow to settle.

2.
Remove headlamp bezels.

3.
Mount the T-3 Aimers on either the No. 1 or No. 2

pair of headlamps so that "the points of the headlamps

engage the smooth inner ring of the aimers.
HORIZONTAL

AIMING

SCREW

STRING OVER

"2R" ON AIMER ARM

Fig.
4—-Headlamp Horizontal Adjustment

NOTE:
In the dual headlamp installation, the

inboard unit is designated No. 1 and the outboard

unit is designated No. 2.

4.
Secure the aimers to the headlamp units by firmly

pressing knob at center of each aimer (fig. 3). Ro-

tate crossarms inboard to approximate horizontal

position.

NOTE:
Moisten suction cups slightly to obtain

maximum holding force.

5. With both aimers in place, knot both ends of elastic

string and, using slots provided, fasten string across

horizontal crossarms of each aimer.

6. Rotate both aimers so that the string just clears the

points on the crossarms.

HORIZONTAL ADJUSTMENT

7. a. Turn horizontal aiming screw, Figure 4, on left-

VERTICAL ADJUSTMENT SCREW

Fig.
3 - Installing Aimer on Headlamp Unit
Fig.
5 - Headlamp Vertical Adjustment

CHEVROLET CHASSIS SERVICE MANUAL

ELECTRICAL-BODY AND CHASSIS 12-34

5. To replace, reverse the removal procedure.

SPEEDOMETER REPLACEMENT

1.
Remove instrument cluster as previously described

in this section.

2.
Remove clock set shaft knob.

3.
Remove eight screws securing cluster housing to

bezel trim panel. Separate parts carefully observing

stack up of parts.

4.
Remove two screws securing speedometer head to

rear of cluster housing.

NOTE:
Servicing of the speedometer head

should be performed by an authorized AC Speed-

ometer Service Station.

5. To install, reverse the removal procedure..

SPEEDOMETER CABLE

Replacement or Lubricatibn

1.
Disconnect the speedometer cable from the speed-

ometer head. Remove the old cable by pulling it out

from speedometer end of conduit.

NOTE:
If old cable is broken it may be neces-

sary to remove lower piece from transmission

end of conduit.

2.
Lubricate the lower 3/4 of cable with speedometer

cable lubricant and push the cable into the conduit.

Connect the upper end to the speedometer head and

road test vehicle for proper speedometer operation.

INDICATOR LIGHT REPLACEMENT

To replace any indicator or cluster bulb, unsnap the

proper socket from rear of instrument cluster, remove

and replace bulb, and reinsert unit into rear of cluster

housing.

OIL PRESSURE INDICATOR

If the light does not come on when the ignition switch
is turned on, or if the light comes on and remains on

after the engine is started, one or more of the following

conditions is indicated:

• Low oil pressure

• High engine temperature

• Defective wiring or switch

Switch Replacement

1.
Disconnect wiring harness connector from sender

unit terminal (located in block above starter on

L-6 engines and at left front of distributor on V-8

engines).

2.
Remove sender unit, replace with new unit, and

; check operation.

GENERATOR INDICATOR

1.
Ignition on, engine not running and telltale light off.

a. Indicator bulb burned out, replace bulb.

b.
Open circuit or loose connection in the telltale

light circuit.

2.
Telltale light stays on after engine is started.

a. If indicator light does not go out at engine idle

speed, refer to Charging Systems under Engine

Electrical, Section 6Y.

TEMPERATURE (COOLING SYSTEM) INDICATOR

The temperature indicator circuit consists of two re-

motely located units, indicator gauge and engine sender

unit. The indicator gauge on all models uses a single

red light to indicate an overheated engine condition.

Engine Sender Unit Replacement

1.
Drain engine cooling system to a level below unit.

2.
Remove sender unit (located in the inlet manifold

near water pump housing on V-8 engines and in the

cylinder head near an exhaust port on L-6 engines)

and replace with new unit.

3.
Refill cooling system and check operation of unit.

CORVETTE INSTRUMENTS AND GAUGES

INDEX

Page

General Description ., 12-34

Service Operations . 12-35

Instrument Cluster ., 12-35

Fuel Gauge 12-35
Speedometer/Tachometer Service. 12-35

Temperature Gauge 12-35

Ammeter/Oil Pressure Gauges 12-35

GENERAL DESCRIPTION

All Corvette instruments and gauges are conveniently

located in the dash-mounted cluster. The entire cluster

is removable to permit servicing of the various instru-

ments and gauges. The indicator and cluster illuminating

bulbs may be replaced without removing the cluster from

the panel.
Regular maintenance is not required on the instrument

cluster or its components other than maintaining clean

and keeping the speedometer and tachometer cables

properly lubricated.

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 15-7

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