oil filter CHEVROLET CAMARO 1967 1.G Chassis User Guide

SECTION 6M

ENGINE FUEL

CONTENTS OF THIS SECTION

Page

Carburetors 6M-1 Fuel Pumps .

Air Cleaners 6M-7 Special Tools
Page

6M-10

6M-12

CARBURETORS

INDEX

Page

General Description 6M-1

Service Procedures 6M-1

Preliminary Checks 6M-1

Idle Speed and Mixture Adjustment ........... 6M-1

Fast Idle Adjustment .................. 6M-3

Choke Adjustment 6M-3

Float Adjustment 6M-4
Page

Additional Adjustments 6M-4

Removal 6M-4

Test Before Installation 6M-5

Installation 6M-5

Fuel Filter Maintenance 6M-5

Choke Coil Replacement 6M-5

Throttle Linkage Adjustment . . 6M-6

GENERAL DESCRIPTION

Various carburetors (fig. lc) are used with Chevrolet,

Chevelle, Chevy II, Camaro and Corvette passenger

vehicles. These carburetors are designed to meet the

particular requirements of engines, transmissions and

vehicles, therefore carburetors that look alike are not

always interchangeable. (Refer to carburetor part num-

ber and/or specifications.)

Because many service procedures for the various

carburetors are similar, typical illustrations and pro-

cedures are used except where specific illustrations or
procedures are necessary to clarify the operation.

This section covers removal, installation and adjust-

ments (on engine) of carburetors. Also covered in this

section are maintenance procedures for choke coils,

throttle linkage and fuel filters. For carburetor .over-

haul procedures and additional adjustments (bench), re-

fer to Section 6M of the Overhaul Manual under the

carburetor being serviced.

Specifications for carburetors are located in the back

of this manual.

SERVICE PROCEDURES

Preliminary Checks

1.
Thoroughly warm-up engine. If the engine is cold,

allow to run for at least 15 minutes.

2.
Inspect torque of carburetor to intake manifold bolts

and intake manifold to cylinder head bolts to exclude

the possibility of air leaks.

3.
Inspect manifold heat control valve (if used) for free-

dom of action and correct spring tension.

Idle Speed and Mixture Adjustment (Except Air Injection

Reactor System)

NOTE:
This adjustment should be performed

with engine at operating temperature and park-

ing brake applied.

1.
Remove Air Cleaner.

2.
Connect tachometer and vacuum gauge to engine, then

set hand brake and shift transmission into neutral.

3.
As a preliminary adjustment, turn idle mixture

screws lightly to seat and back out 1-1/2 turns.

CAUTION: Do not turn idle mixture screw

tightly against seat or damage may result.

4.
With engine running (choke wide open) adjust idle
speed screw to specified idle speed, (automatic

transmission in drive, synchronized transmission in

neutral).

5. Adjust idle mixture screw to obtain highest steady

vacuum at specified idle speed.

NOTE:
On air conditioned vehicles, turn air

conditioning to the "on" position and hold the

hot idle compensator valve closed while adjust-

ing idle speed and idle mixture screws.

NOTE:
On Rochester BV carburetors the idle

mixture screw should be turned out 1/4 turn

from the "lean roll" position. The definition

of "lean roll" point is a 20 to 30 rpm drop

in engine speed obtained by leaning the idle

mixture.

6. Repeat Steps 4 and5 as needed for final adjustment.

NOTE:
If necessary, final adjustment of the \

carburetor may be made with the air cleaner

installed.

7. Turn engine off, remove gauges and install air

clearer.

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE FUEL 6M-5

3.
Disconnect choke rod or choke cable.

4.
Disconnect accelerator linkage.

5.
If equipped with Automatic transmission, discon-

nect TV linkage.

6. Remove carburetor attaching nuts and/or bolts and

remove carburetor.

Test Before Installation -

It is good shop practice to fill the carburetor bowl

before installing the carburetor. This reduces the strain

on the starting motor and battery and reduces the pos-

sibility of backfiring while attempting to start the engine.

A fuel pump clamped to the bench, a small supply of fuel

and the necessary fittings enable the carburetor to be

filled1 and the operation of the float and'intake needle and

seat to be checked. Operate the throttle several times

and check the discharge from the pump jets before in-

stalling the carburetor.

Installation

1.
Be certain throttle body and intake manifold sealing

surfaces are clean.

2.
Install new carburetor to manifold flange gasket (if

required).

3.
Install carburetor over manifold studs.

4.
Start vacuum and fuel lines at carburetor.

5.
Install attaching nuts and/or bolts and tighten

securely.

6. Tighten fuel and vacuum lines.

7.
Connect and adjust accelerator and TV linkage.

8. Connect choke tube or choke rod.

9. Adjust idle speed and mixture, then install air

cleaner. #

Fuel Filter Maintenance

1.
Disconnect fuel line connection at inlet fuel filter

nut.

2.
Remove inlet fuel filter nut from carburetor with a

1"
box wrench or socket.

3.
Remove filter element and spring (fig. 4c).
Fig. 5C-Choke Coil-L6 Engine

4.

Fig. 4C-Fuel Filter
Check element for restriction by blowing on cone

end, element should allow air to pass freely.

5.
Clean element by washing in solvent and blowing out.

Blow in opposite direction of fuel flow.

NOTE: Element should be replaced if plugged

or if flooding ocpurs. A plugged filter will

result in a loss of engine power or rough (pul-

sating) engine feel, especially at high engine

speeds.

6. Install element spring, then install element in car-

buretor so small section of cone faces out.

7.
Install new gasket on inlet fitting nut then install

nut in carburetor and tighten securely.

8. Install fuel line and tighten connector.

Choke Coil Replacement

L6 Engines (Fig. 5c)

1.
Remove air cleaner then disconnect choke rod upper

clip.

2.
Remove bolts attaching choke coil to manifold, then

remove choke coil and choke rod as an assembly.

3.
Disconnect choke rod from choke coil.

4.
Connect choke rod to new choke coil and install as-

sembly on manifold.

5.
Install bolts and tighten securely.

6. Adjust and connect choke rod as outlined.

7.
Start and warm-up the engine then check operation

of choke and install air cleaner.

V8 Engines (Fig. 6c)

1.
Remove air cleaner then disconnect choke rod upper

clip.

2.
Remove choke coil as follows:

WITH ROCHESTER 2GV CARBURETOR

• Remove the choke coil shield by prying with a

screw driver in the cut out provided then re-

move the choke rod.

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE FUEL 6M-7

5. On vehicles equipped with automatic transmission

hold throttle rod in full throttle position, pull TV

rod to full detent position and adjust TV rod to just

enter hole on throttle lever, then connect TV rod at

throttle lever.
NOTE:
If equipped with anti-stall device (dash-

pot),
set carburetor fast idle cam on high step

and adjust dash-pot to just contact throttle

lever.

327
CU.
IN.
427
CU.
IN.

Fig.
8C—Throttle Linkage-Corvette

AIR
CLEANERS

INDEX

Page

General Description 6M-7

Service Procedures . . 6M-8

Polyurethane. Element 6M-8

Maintenance 6M-8

Oil Bath 6M-8
Page

Maintenance
...........* 6M-8

Oil
Wetted
Paper
Element
6M-9

Replacement
* . 6M-9

Testing 6M-9

Tool J-7852 . 6M-9

GENERAL DESCRIPTION

Air cleaners on all models operate primarily to re-

move dust and dirt from the air that is taken into the

carburetor and engine. All air cleaners on engines

equipped with "Closed Positive" ventilation incorporate

flame arresters. Every 12,000 miles the flame ar-

resters should be removed, cleaned in solvent and blown

dry with compressed air.

An oil wetted polyurethane element air cleaner (fig. 1A)

is standard equipment on In Line engines. This type

cleaner element is reusable and should be removed,

cleaned, re-oiled and reinstalled every 12,000 miles or

more often during dusty or other adverse driving con-

ditions. The optional, oil bath air cleaner (available on
Chevrolets with L6 engine) should be cleaned and re-

filled with oil at oil change intervals.

On the V8 engines,, a replaceable, oil wetted paper

element type is used (fig; 2A). Both ends of me paper

element are bonded with plastisol sealing material.

The improved oil wetted paper elements have increased

filtering capacity over their dry paper predecessors.

Oil on the paper causes the element to become diBcolored

by a small amount of dirt but does not necessarily mean

the element is plugged or reduced in efficiency. Every

12,000 miles or more often during dusty or other adverse

driving conditions, either replace oil wetted paper ele-

ment or test element using ToolJ-7825.

CHEVROLET CHASSIS SOVICE/MANUAL

ENGINE FUEL 6M-8

^T^l^^/'-vN

COVER
BOTTOM

Fig. 1A—Polyurethane Element Air Cleaner
OIL RESISTANCE

SEAL

BOTTOM
BONDED PAPER

ELEMENT

COVER

Fig. 2A—Paper Element Air Cleaner

SERVICE
PROCEDURES

POLYURETHANE ELEMENT

Maintenance

1.
Remove cover wing nut, cover and filter element.

2.
Visibly check the element for tears or rips and re-

place if necessary.

3.
Clean all accumulated dirt and grime from air

cleaner bottom and cover. Discard air horn to air

cleaner gasket.

4.
/Remove support screen from element and wash

element in kerosene or mineral spirits; then squeeze

out excess solvent (fig. 3A).

NOTE: Never use a hot degreaser or any sol-

vent containing acetone or similar solvent*

5.
Dip element into light engine oil and squeeze out

excess oil.
NOTE: Never shake, swing or wring the ele-

me.nt to remove excess oil or solvent as this

may tear the polyurethane material. Instead,

"squeeze" the excess from the element.

6. Install element'on screen support (fig. 4A).

7.
Using a new gasket, replace air cleaner body over

carburetor air horn.

8. Replace the element in the air cleaner. Care must

be taken that the lower lip of the element is properly

placed in the assembly and that the filter material

is not folded or creased in any manner that would

cause an imperfect seal. Take the same precautions

when replacing the cover that the upper lip of the

element is in proper position.

9.<•
Replace cover and wing nut.

OIL BATH

Maintenance

L Remove air cleaner assembly.

2.
Remove cover and filter element assembly.

Empty oil out of

accumulated dirt.
cleaner and clean out all oil and

Fig. 3A—Cleaning Polyurethane Element

Fig.
4A—Polyurethane Support

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE FUEL 6M-9

4.
Wash body with cleaning solvent and wip dry.

5. Wash filter element by sloshing up and down in

cleaning solvent.

6. Dry filter unit with an air hose or let stand until

dry.

7. Fill body of cleaner to full mark with SAE 50 engine

oil. If expected temperatures are to be consistently

below freezing, use SAE 20 engine oil.

8. Assemble filter and cover assembly to body of

cleaner.

9. Install cleaner, making sure it fits tight and is set

down securely. \

OIL
WETTED
PAPER
ELEMENT

Replacement

1.
Remove wing nut, washer and cover.

2.
Remove paper element and discard.

3.
Remove bottom section of air cleaner and gasket

on air horn of carburetor. Discard air horn gasket.

4.
Clean bottom section of air cleaner and cover pieces

thoroughly, to remove dust and grime.

NOTE:
Check bottom section of air cleaner

seal for tears or cracks.

5. Install a new gasket on carburetor air horn and set

bottom section of air cleaner on carburetor.

6. Install new paper element on bottom section of air

cleaner with either end up.

NOTE:
Plastisol seal is the same material on

both ends.

7. Install cover, washer and wing nut.

Testing (Fig. 5A)

Tool J-7825, is designed to check paper element air

cleaners to determine whether the element has ma-

terially decreased in efficiency arid should be replaced

or has only slightly increased air restriction and is

suitable for further service. In combination with a

tachometer, this instrument will quickly and accurately

determine the air cleaner element condition.

VENT HOLE

TOWARD DASH
NOTE:
t Before testing, inspect for holes or

breaks in the element, as these defects re-

quire immediate replacement. If no holes or

breaks exist, proceed as follows:

1.
Remove all hoses and plug all openings except air

cleaner inlet.

2.
Install air cleaner, using Tool J-7825 in place of the

wing nut. Screw Tool J-7825 onto the stud until it

seals tightly against the air cleaner cover. Rotate

the entire tool so that the scale can be read from

the left side of the car. Be sure the vent hole is

toward the dash.

3.
Connect a tachometer and place it so that it may be

read simultaneously with Tool J-7825.

4.
Zero oil level in the inner tube by pulling inner tube

upward until the rubber seal is above the vent hole,

then raise or lower as' required until the inner tube

oil level is exactly to the "0" mark.

5. Start engine. If engine is cold, allow to run for 2 to

3 minutes. The automatic choke must be fully open.

6. Accelerate the engine slowly until the inner tube oil

level of Tool J-7825 just reaches the 1/4 mark.

Allow engine speed to stabilize and note tachometer

(rpm) reading. Decelerate engine.

7. If the tachometer reading is at or below the follow-

ing, the oil wetted paper air cleaner element is re-

stricted beyond the allowable limit and should be

replaced. If testing indicates that the element

restriction is satisfactory at 12,000 miles, the ele-

ment need not be replaced but should be retested

every 6,000 miles thereafter until replaced.

Engine

Displacement

283 cu.
in.

327 cu.
in.

350 cu. in.

396 cu.
in.

427 cu.
in.
Horsepower

195

210

275

300

325

350

295

325

350

385

390

425
Minimum

Allowable

RPM

2300

2100

210Q

2600

2600

1550

1950

1850

1850

2140

Fig.
5A—Testing Air Cleaner
8. Remove tachometer and Tool J-7825 from vehicle

and push down inner tube until seal is below vent

hole to prevent oil loss.

Tool J-7825

FiHing
Tool

Tool J-7825 is shipped dry and must be filled with the

red gauge oil (specific gravity .826) provided.

Pull the knurled inner tube completely out of the gauge

and add oil to the reservoir until the oil level is between

CHEVROLET CHASSIS SERVICE /MANUAL

CLUTCH AND TRANSMISSIONS 7-33

from rolling. The pointer on the indicator quadrant

should line up properly with the range indicators in all

ranges.

OIL LEAKS

Before attempting to correct an oil leak, the actual

source of the leak must be determined. In many cases

the source of the leak can be deceiving due to "wind flow1 f

around the engine and transmission.

The suspected area should be wiped clean of all oil

before inspecting for the source of the leak. Red dye is

used in the transmission oil at the assembly plant and

will indicate if the oil leak is from the transmission.

The use of a "black light"* to identify the oil at the

source of leak is also helpful. Comparing the oil from

the leak to that on the engine or transmission dip stick

(when viewed by black light) will determine the source

of the leak.

Oil leaks around the engine and transmission are gen-

erally carried toward the rear of the car by the air

stream. For example, a transmission "oil filter tube

to case leak" will sometimes appear as a leak at the

rear of the transmission. In determining the source of

an oil leak it is most helpful to keep the engine running.

The mating surfaces of servo cover, converter housing,

transmission case and transmission case extension

should be carefully examined for signs of leakage. The

vacuum modulator must also be checked to insure that

the diaphragm has not ruptured as this would allow trans-

mission oil to be drawn into the intake manifold. Us-

ually, the exhaust will be excessively smoky if the

diaphragm ruptures due to the transmission oil added to

the combustion. The transmission case extension rear

oil seal should also be checked. All test plugs should be

checked to make sure that they are tight and that there

is no sign of leakage at these points. The converter

underpan should also be removed. Any appreciable quan-

tity of oil in this area would indicate leakage at the pump

square seal ring, pump seal assembly, or pump bolt

sealing washers.

BASIC PRESSURE CHECKS

Four basic pressure checks are used for diagnosis and

operational checks for the Aluminum Powerglide trans-

mission. All checks should be made only after thoroughly

warming up the transmission.

• Wide Open Throttle Upshift Pressure.

• Idle Pressure in "Drive" Range.

• Manual "Low" Range Pressure.

• "Drive" Range Overrun (Coast) Pressure.

It is not recommended that stall tests be conducted

which would result in engine vacuum falling below 10" Hg.

Pressure gauge hose connections should be made at

the low servo apply (main line) test point (fig. 14PG).

Run the gauge line into the driving compartment by

pushing aside the mast jacket seal. The line out of the

way of the drivers feet and connect to pressure gauge

J-21867.

• Wide Open Throttle Upshift Pressure Check

Refer to the pressure check chart for upshift pressure
SERVO APPLY

PRESSURE

Fig.
14PG - Pressure Test Plug

points as indicated on the lower servo apply (main line)

gauge.

• Idle Pressure in "Drive" Range

In addition tp the oil pressure gauges, a vacuum gauge

is needed for this check.

With the parking brake applied and the shift selector

lever in "Drive", low servo apply (main line) pressure

should be as shown on the pressure check chart.

If pressures are not within these ranges, the following

items should be checked for oil circuit leakage:

1.
Pressure regulator valve stuck.

2.
Vacuum modulator valve stuck.

3.
Hydraulic modulator valve stuck.

4.
Leak at low servo piston ring (between ring and

bore).

5.
Leak at low servo piston rod (between rod and bore).

6. Leak at valve body to case gasket.

7.
Leak at valve body gaskets.

8. Front pump clearances.

9. Check passages in transmission case for porosity.

• Manual "Low" Range Pressure Check

Connect a tachometer, apply the parking brake, place

the selector lever in "Low" range, and adjust the engine

speed to 1000 rpm with the car stationary.

Low servo apply (main line) pressure should be as

shown on the pressure check chart.

Pressures not within this range can indicate the fol-

lowing possibilities:

1.
Partially plugged oil suction screen.

2.
Broken or damaged ring low servo.

CHEVROLET CHASSIS SERVICE MANUAL

driven disk is sandwiched between the magnetic disk and

a field plate. The field plate forms a returning path for

the magnetic field from the magnetic disk.

The gear drive for the magnetic disk is a 90 degree

nylon gear drive with the driven gear rotating both the

magnetic disK and the speedometer drive cable.

Vacuum Switch, Air Bleed and Filter, and Low

Limit Speed Switch

The end of the shaft from the speed sensing assembly

with the rubber drum extends into the air bleed metering

assembly. This rubber drum has a tang extending from

its surface which allows a set of points to close at a

specific car speed. When the car reaches about 20 mph,

the rubber drum has rotated far enough (moved by the

brass driven disk in the magnetic field) so that its tang

has allowed a spring loaded electrical point to contact

another point. These points are in series with the sole-

noid coil so that under 20 mph, no Regulator operation

is possible.

Surrounding the rubber drum is a "U" shaped spring

clip which is held spread away from the drum by the

nose or cam of the solenoid when the solenoid is in the

relaxed position. The rubber drum and this clip com-

prise the speed clutch of the regulator. When the sole-

noid is energized, the solenoid nose moves toward the

drum and releases the ends of the clip. The clip springs

inward and attaches itself by friction to the drum. Now,
ACCESSORIES 15-5

any change in car speed will rotate the drum and move

the "U" clip just as a speedometer moves its needle.

The top of the MUtf clip is attached to the air bleed valve.

The clip moves a sleeve which slides on the orifice

tube thereby covering and uncovering air ports in the

wall of the tube (the tube inner end is plugged) whenever

car speed changes from the speed at which the solenoid

was energized. The direction of drum rotation is such

that resulting bleed valve operation will cause the Servo

to decrease engine power if the car exceeds the preset

speed and increase engine power if car speed decreases.

The air which passes out the orifice tube enters the

Regulator through the openings in the solenoid housing,

passes through the oil wetted polyurethane filter, and then

enters the orifice tube ports.

When the solenoid is de-energized, the nose retracts

and cams the ends of the "U" clip outward so that it re-

leases the rubber drum.

The solenoid also operates a vacuum switch simul-

taneously with the clutching and declutching of the "U"

clip.
The vacuum switch supplies the Servo unit with

manifold vacuum. The solenoid operated vacuum valve

slides over two ports in the Regulator wall. One port

is connected to manifold vacuum and the other is con-

nected to the center port of the Servo unit. When the

solenoid is de-energized, the valve closes the manifold

vacuum port and opens the Servo port to the inside of

the regulator case. When the solenoid is energized, the

valve connects the Servo port to the manifold vacuum

AAAGNET

SPEED CUP

FIELD PLATE

HAIRSPRING
TO SPEEDOMETER

MAGNET HOUSING

ASSEMBLY
ORIFICE TUBE &

CONNECTOR ASSEM.
CONTROL

VALVE

CLUTCH

SPRING

LOW LIMIT

SPEED SWITCH

RUBBER

DRUM

VACUUM PORT

TO SERVO

INPUT CONNECTION

SOLENOID COIL

SOLENOID AND CLUTCH

HOUSING ASSEMBLY
VACUUM PORT

TO ENGINE

VACUUM VALVE

UNLOCKING CAM

•SOLENOID PLUNGER

AIR FILTER

SIDE VIEW SECTION

REGULATOR DISENGAGED
END VIEW SECTION

ENGAGED

Fig.
8 - Regulator-Cross Section '

CHEVROLET CHASSIS SERVICE MANUAL

ACCESSORIES
15-6

port thereby supplying vacuum to the Servo unit.

During system operation
the
following events occur:

1.
Car
speed below
20
mph—no function
of the
unit

because
the
rubber drum
has
not rotated
far
enough

to close
the
solenoid points.
No
energizing current

can flow through the solenoid coil.

2.
Car
speed above
20
mph—The tang
on the
rubber

drum
has
closed
the
solenoid points
and
current
is

flowing through
the 40 ohm
resistance wire
to the

solenoid coil. This current
is
not sufficient to "pull

in", the solenoid.

3.
Driver partially presses Engagement Switch—full

voltage flows through
the
solenoid
to
pull
it
into

operation. Solenoid
cam
tension
on the "U"
clip
is

released and the clip grips the rubber drum. Simul-

taneously the vacuum switch operates; applying man-

ifold vacuum
to the
Servo unit which tightens
the

throttle chain. When
the
driver releases pressure

from
the
accelerator pedal
the
unit will position the

throttle
to
maintain the speed
at
the time
of
solenoid
operation.

Driver releases
the
Engagement Switch—current

flows
to the
solenoid through
the 40
ohm wire and

since the solenoid is "pulled in", the reduced current

flow
is
sufficient to hold
it
in position.

The
car
begins
to
ascend
a
hill—car speed drops

slightly (very slightly) and the magnetic force on the

driven disk
of the
speed sensor
is
decreased.
The

disk rotates slightly
(as
would
a
speedometer shaft

because
of
hairspring tension) turning
the
rubber

drum. Since
the "U"
clip
is
gripping
the
drum,
it

moves
the
slide which COVERS
the air
bleed ports

more. With less air bleeding into the Servo, greater

vacuum exists
in it
and the diaphragm moves toward

the vacuum port opening
the
throttle wider.
The

tapered needle moves into the orifice further and the

diaphragm balances
in a
new position with the wider

throttle opening.
Car
speed
has
been maintained

automatically.

1.
Speedometer Cable

Adapter (From

Transmission)

2.
Gasket

3. Speedometer Cable

Adapter
(To

Speedometer)

4.
Adapter
and
Magnet

Housing

5. Rotating Magnet

6. Helical Ramp
7. Field Plate Adjusting

Pinion

8. Adjusting Pinion

Locating Spring

9. Brass Magnetically

Driven Disk

10.
Field Plate

11.
Hair Spring

12.
Hair Spring Keeper

13.
Rubber Drum

Tang
14.
Rubber Drum

1$.
"U"
Shaped Clutch

Spring

16.
Air
Bleed Sleeve

17.
Orifice Tube

18.
Orifice

19.
Orifice Tube Locknut

20.
Clutch
and
Solenoid

Housing

21.
Vacuum Supply Port

(To Servo)
22.
Vacuum Port (To

Intake Manifold)

23.
Vacuum Valve Slide

24.
Solenoid Coil

25.
Solenoid Plunger

Return Spring

26.
Solenoid Cover Gasket

27.
Air Filter

28.
Solenoid Cover

29.
Air Inlets

Fig.
9-
Regulator
-
Exploded

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