1967 CHEVROLET CAMARO brake light

BRAKES 5-15

Brake Shoes

Refer to parking brake shoe service procedures under

Disc Brakes in this section.

BRAKE PEDAL (Fig. 26)

Removal

NOTE: Refer to Section 1A for removal

air conditioning components if necessary.
of

1.

5.

b.

c.
Disconnect clutch pedal return spring (manual trans-

mission models only).

Disconnect clutch push rod at pedal.

Disconnect brake pedal return spring (Chevelle and

Camaro only).

Disconnect brake pedal from main cylinder push

rod by removing retainer and clevis pin.

Corvette only:

a. Remove steering column from vehicle as outlined

in Section 9.

Support main cylinder frdm inside engine com-

partment and remove four support brace nuts.

Remove four nuts and bolts securing support

plate to bracket and remove support plate.

d. Remove two screws securing bracket to under-

side of instrument panel and lower bracket and

pedals to floor.

Remove retainer from right side of pedal pivot

shaft.

7.
Slide clutch pedal assembly to the left and remove

from support brace.

8. Withdraw brake pedal and all nylon bushings.

Inspection

1.
Clean all metal parts with a good nontoxic cleaning

solvent.

2.
Wipe nylon bushings clean with a clean cloth.
6
CAUTION: Nylon bushings should not be treated

with cleaning agent of any nature.

3.
Inspect all nylon bushings for wear and damage.

4.
Inspect mating surface of bushings for wear and

damage—replace parts as required.

Installation

1.
Lubricate and install nylon bushings on pedal pivot

shaft, right side of support brace cutout, and through

both ends of brake pedal bore.

2.
Chevrolet, Chevy n, and Corvette: Position brake

pedal return spring on pedal arm and place pedal

assembly in support brace. Index return spring in

support brace cutout.

3.
Chevelle and Camaro: Place pedal assembly in

support brace.

4.
Slide pedal pivot shaft through support brace and

brake pedal bore.

5.
Install retainer to right side of pedal pivot shaft.

6. Corvette only:

a. Install bracket with pedal assemblies to underside

of instrument panel with two screws.

b.
Install support plate on bracket with four bolts

and nuts. • • ' •

c. Place main cylinder in position and install four

bracket and cylinder mounting bolts; secure en-

tire assembly with four nuts.

d. Install steering column in vehicle as outlined

in Section 9.

7.
Chevelle and Camaro: Install brake pedal return

spring.

8. On manual transmission models, connect clutch pedal

push rod to pedal bracket and install retainer. In-

stall clutch pedal return spring.

9. Adjust brake pedal free travel as outlined in this

section. Adjust stoplight switch as outlined in Section

CHEVROLET

CHEVELLE

Fig.
26—Brake Pedal Installation

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-16

6Y. Adjust clutch pedal travel as outlined in

Section 7.

SHOES AND LININGS

Organic Linings

NOTE:
If brake drums are worn severely, it

may be necessary to retract the adjusting screw.

To gain access to the adjusting screw star

wheel, knock out the lanced area in the web of

the brake drum using a chisel or similar tool.

Release the actuator from the star wheel by

lifting with a small screw driver and back off

the star wheel with a second screw driver (press

down on the handle to retract shoes).

CAUTION: After knocking out the metal, be

sure to remove it from the inside of the drum .

and clean all metal from the brake compartment.

A new hole cover must be installed when drum

is reinstalled.

Removal

1.
Raise the vehicle and plate on jack stands.

2.
Loosen check nuts at parking brake equalizer suffi-

ciently to remove, all tension from brake cable.

3.
Remove brake drums.

NOTE:
Since there are wheel cylinder piston

stops to prevent pistons from leaving cylinders,

it is not necessary to install wheel cylinder

clamps when brake shoes are removed; however,

brake pedal must not be depressed while drums

are removed.

4.
Unhook brake shoe pull back springs from anchor

pin and link end, using Tool J-8049 (fig. 27).

5. Remove the actuator return spring and link.

6. Remove hold-down pins and springs (fig. 28).

7. Remove the actuator assembly.
NOTE:
The actuator, pivot and override spring

are an assembly. It is not recommended that

they be disassembled for service purposes,

unless they are broken. It is much easier to

assemble and disassemble the brakes by leaving

them intact.

8. Separate the brake shoes by removing adjusting

screw and spring.

9. Remove parking brake lever from secondary brake

shoe (rear only).

Inspection

1.
Clean all dirt out of brake drum using care to avoid

getting dirt into front wheel bearings. Inspect drums

for roughness, scoring or out-of-round. Replace or

recondition drums as required.

2.
Inspect wheel bearings and oil seal, and replace

any necessary parts.

3.
On Chevrolet only:

Carefully pull lower edges of wheel cylinder boots

away from cylinders and note whether interior is

wet with brake fluid. Excessive fluid at this point

indicates leakage past piston cups and a need for

wheel cylinder overhaul or replacement.

NOTE:
A slight amount of fluid is nearly always

present and acts as lubricant for the piston.

4.
Check cylinders with internal boots by carefully pull-

ing a small part of the boot out of the cylinder.

Note whether interior is wet with brake fluid. Ex-

cessive fluid at this point indicates leakage past

piston cups and a need for wheel cylinder overhaul

or replacement.

5. Check all brake flange plate attaching bolts to make

sure that they are tight. Clean all rust and dirt

from shoe contact faces on flange plate (fig. 29),

using fine emery cloth.

Installation

CAUTION: Make certain to install recom-

Fig.
27-Unhooking Pull Back Spring
Fig.
28—Removing Hold-Down Springs and Pins

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-22

2.
Replace ail push rods and pull back springs.

3.
Connect hose or line to wheel cylinder.

NOTE:
If replacing front wheel cylinder, con-

nect hose and inspect installation as outlined in

"Hydraulic Brake Hose Replacement".

4.
Install drum and wheel.

5. Bleed brakes as outlined in this section.

ANCHOR PIN

Front Wheel

1.
Raise front of vehicle and place on jack stands.

2.
Remove wheel and drum as outlined in this section.

3.
Remove brake shoe pull back springs, link and guide

plate.

4.
Disengage anchor pin lock and remove anchor pin by

turning counterclockwise.

5. Place new lock plate on anchor pin and pass pin

through the hole in flange plate and screw into tapped

hole in spindle support.

6. Torque pin to 130 lb. ft. and lock by peening over

washer tabs.

7. Install brake shoe guide plate, link and pull back

springs.

8. Adjust brakes, install drum and wheel as outlined

in this section. Test brake operation.

Rear Wheel

Two type anchor pins are used in production for the

rear wheels. The riveted type is not serviced and if

failure or damage should occur to either the anchor

pin or flange plate, both parts will have to be replaced

and the threaded type anchor pin used.

Threaded Type

1.
Raise rear of vehicle and place on jack stands,

2.
Remove wheel and drum as outlined in this section.

3.
Remove brake shoe pull back springs, link and guide

plate.

4.
Remove anchor pin retaining nut and washer and

remove pin from flange plate.

5. Position anchor pin to flange plate, install lock

washer and nut, and torque pin to 80 lb. ft.

6. Install brake shoe guide plate, link and pull back

springs.

7. Adjust brakes and install drum and wheel as outlined

in this section.

8. Test brake operation.

BRAKE DRUMS

Front brake drums are the demountable type; that is,

they can be removed without removing the hub. Rear

brake drums are demountable and may be removed

wihtout removing the axle shaft.

A lanced "knock out" area (fig. 34) is provided in

the web of the brake drum for servicing purposes in

the event retracting of the brake shoes is required in

order to remove the drum.

A small screw driver or hooked wire may be inserted

to disengage the automatic adjuster actuating lever so

the star wheel may be turned.

Removal

1.
Raise vehicle and place on jack stand.
2.
Remove wheel and tire assembly, back off brake

adjustment and remove drum.

Inspection and Reconditioning

Whenever brake drums are removed they should be

thoroughly cleaned and inspected for cracks, scores,

deep grooves, and out-of-round. Any of these conditions

must be corrected since they can impair the efficiency

of brake operation and also can cause premature failure

of other parts.

Smooth up any slight scores by polishing with fine

emery cloth. Heavy or extensive scoring will cause

excessive brake lining wear and it will probably be

necessary to rebore in order to true up the braking

surface.

An out-of-round drum makes accurate brake shoe

adjustment impossible and is likely to cause excessive

wear of other parts of brake mechanism due to its

eccentric action.

A drum that is more than .008" out-of-round on the

diameter is unfit for service and should be rebored.

Out-of^round, as well as taper and wear can be ac-

curately measured with an inside micrometer fitted

with proper extension rods.

If drum is to be rebored for use with standard size

brake facings which are worn very little, only enough

metal should be removed to obtain a true smooth braking

surface.

If drum has to be rebored more than .020" over the

standard diameter, it should be rebored to .060" diameter

oversize and the brake facing should be replaced with

.030"
oversize facings.

A brake drum must not be rebored more than .060"

over the maximum standard diameter, since removal

of more metal will effect, dissipation of heat and may

cause distortion of drum. Chevrolet brake facing is

not furnished larger than .030" oversize and this will

not work efficiently in drums bored more than .060"

oversize.

Brake drums may be refinished either by turning or

grinding. Best brake performance is obtained by turning

drums with a very fine feed. To insure maximum lining

life,
the refinished braking surface must be smooth and

free from chatter or tool marks, and run-out must not

exceed .005" total indicator reading.

Cleaning

New brake drums in parts stock are given a light.

coating of rust proofing oil to prevent the formation of

rust on the critical braking surfaces during the time

that the drums are in storage.

This rust proofing oil must be carefully removed

before the drum is placed in service to prevent any

of this oil from getting on the brake shoe facings, which

might cause an extreme brake grab condition.

It is recommended that a suitable volatile, non-toxic,

greaseless type solvent be used to clean the oil from the

braking surface of the new brake drums before they are

•placed in service to insure the cleanest possible surface.

Gasoline or kerosene should not be used as there is

danger that a portion of the diluated oil substance may

be left on the braking surface that may later cause

difficulty.

Installation

1.
Make brake adjustment as outlined in this section.

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES
5-24

DISC BRAKES

INDEX

Page

General Description
. 5-24

Maintenance
and
Adjustments
5-24

Bleeding Hydraulic System
5-24

Parking Brake Adjustment
-
Corvette
5-24

Component Replacement
and
Repairs
5-25
Page

Brake Shoes
. . . . . 5-25

Brake Caliper
5-26

Brake Disc
5-29

Main Cylinder.
5-30

Parking Brake Shoes
-
Corvette
5-30

GENERAL DESCRIPTION

Four wheel disc brakes
are
standard equipment
on

the
1967
Corvette,
as in 1966. The
Corvette
may
also

be equipped with heavy duty disc brakes which include

new front calipers, shoes, linings,
and
rear pressure

regulator valve. This heavy duty option
is
used
in

conjunction with
a
vacuum power unit. Front wheel disc

brakes
are
installed
as
optional equipment
on
Chevrolet,

Chevelle, Camaro,
and
Chevy
II
models.

The disc brake,
(fig. 35),
consists
of a
fixed caliper,

rotating disc, splash shield,
and
mounting bracket.
The

caliper assembly contains four pistons and two shoe
and

lining assemblies with
the
lining riveted
to the
steel

shoes.
A
seal
and
dust boot
are
installed
on
each piston,

with
a
piston spring
in the
caliper cylinder bore beneath

each piston.
A
retaining pin extends through each caliper

half
and
both shoes
to
hold
the
shoes and linings
in
posi-

tion
in the
caliper.
On
Corvette heavy duty disc brakes,

two retaining cotter pins
are
used
at
each end
of the

caliper
to
secure
the
shoes
and
linings. Machined
sur-

faces within
the
caliper prevent
the
shoe
and
lining
assembly from rotating with
the
brake disc when pres-

sure
is
applied.

The disc, which
has a
series
of air
vent louvers
to

provide cooling,
is
mounted
on the
front wheel-hub.

The caliper straddles
the
disc and mounts
on a
mounting

bracket attached
to the
steering knuckle with
two
bolts.

The Corvette heavy duty option includes
a
pressure

regulator valve mounted
in the
rear brake line just

below
the
main cylinder. Chevrolet, Chevelle, Camaro,

and Chevy
n
models with disc brakes have
a
pressure

regulator valve mounted
in the
front brake line just

below
the
main cylinder. The valve controls
the
hydraulic

pressure
to the
front
or
rear brakes,
as
applicable,

resulting,
in the
correct pressure balance between
the

front
and
rear hydraulic systems. This valve guards

against premature .lock-up
of
front
or
rear wheels when

brakes
are
applied.

Maintenance, adjustment,
and
service operations which

are
not
included
in
this section
are the
same
as for

the Duo-Servo type brakes.

MAINTENANCE
AND
ADJUSTMENTS

BLEEDING HYDRAULIC SYSTEM

The operation
of
bleeding
the
disc brake hydraulic

system
is the
same
as for
Duo-Servo system outlined

in
the
front
of
this section. Note
the
exceptions below

and refer
to
bleeding procedures under Duo-Servo

brakes.

1.
When pressure bleeding equipment
is
used,
the

correct pressure setting
for
bleeding disc brakes

is 10-2.0
lbs. on
Corvette,
and 40 lbs. on all
other

models.

2.
The
front calipers contain
one
bleeder valve.
The

rear calipers
on
Corvette contain two bleeder valves

(one inboard
and one
outboard) which necessitates

the removal
of the
rear wheels
for
bleeding.

3.
Tapping
the
caliper with
a
rawhide mallet
as the

fluid
is
flowing
out may
assist
in
obtaining
a
good

bleeding
job.

4.
On
Chevrolet, Chevelle, Camaro
and
Chevy
II, the

spring loaded
end of the
pressure regulator valve

(fig.
36)
must
be
held (valve
in
open position) while

bleeding. This
is
done
by
depressing
and
holding

in
the
plunger
in the
end
of
the valve either
by
hand,

by taping,
or by
clamping.
PARKING BRAKE-CORVETTE

Adjustment

1.
Raise rear
end of
vehicle
and
place
on
jack stands.

2.
Remove rear wheels.

3/
Loosen brake cables
at the
equalizer until
the
park-

ing brake levers move freely
to the "off"
position

with slack
in the
cables.

4.
Turn
the
disc until
the
adjusting screw can
be
seen

through
the
hole
in the
disc.

5. Insert
an
adjusting tool
or
screw driver through
the

hole
in the
disc
and
tighten
the
adjusting screw
by

moving your hand away from
the
floor
on
both
the

left and right sides
(fig. 37).

6. Tighten until
the
disc will
not
move, then back
off

ten
(10)
notches.

7. Apply
the
parking brake four
(4)
notches from inside

the
car.

8. Tighten
the
brake cables
at the
equalizer
to
produce

a light drag with
the
wheels mounted.

9. Fully release
the
parking brake handle
and
rotate

the rear wheels.
No
drag should be evident with
the

handle released.

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-30

CAUTION: Be sure the emergency brake ad-

justing, holes of the spindle and disc are in

alignment.

2.
Install the brake caliper and shoes as outlined in

this section.

3.
Bleed the brakes as outlined in this section.

4.
Install wheel and tire assembly and lower vehicle.

MAIN CYLINDER

The service operations for the main cylinder are the

same as for Duo-Servo main cylinder. Refer to service

procedures under Duo-Servo Brakes.

PARKING BRAKE SHOES

Corvette (Fig. 44)

Removal

1.
Remove tire and wheel assemblies and brake disc

as outlined in this section.

2.
Remove retractor spring at the top of the shoes.

Remove hold down springs on primary and secondary

shoes.

3.
Remove shoes by pulling them away from the anchor

pin.

4.
Remove the adjusting screw spring and adjusting

screw from the shoes.

Installation

1.
Put light coat of lubriplate on pads, backing plate,

and the threads of the adjusting screw.

2.
Attach adjusting screw spring to the bottom hole in

each shoe.

3.
Insert the star wheel between the shoes. (On left

hand brakes, the star wheel goes next to the rear

shoe; on right hand brakes, the star wheel goes next

to
the.
forward shoe).

4.
Install the shoes on the backing plate by spreading

them and placing them around the anchor pin.

5. Install the hold down springs on the hold down nails.
Fig.
44-Exploded View of Parking Brake Shoes

1.
Parking Brake Shoe

2.
Hold Down Spring and Cap

3. Hold Down Pin

4. Actuating Lever

5. Retractor Spring
6. Backing Plate

7. Parking Plate

8. Hold Down Spring and Cap

9. Adjusting Screw Spring

0, Adjusting Screw Assembly

6. Install retractor spring on one shoe and stretch to

other shoe.

CAUTION: Make sure that the lever assembly

which spreads the shoes is located so that the

notches on the lever fit against the shoes.

7. Install disc and caliper as outlined in. this section.

8. Bleed brakes as outlined in this section.

9. Adjust the parking brake as outlined in this section.

10.
Install wheels and lower vehicle.

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES
5-31

POWER BRAKES

INDEX

General Description 5-31

Maintenance
and"
Adjustments 5-31

Inspection . ... 5_31

Lubrication 5-31

Bleeding Instructions . . . 5.31

Air Cleaner Service . . . , 5.31
Page

Component Replacement 5-31

Power Brake Cylinder ......* 5-31

Removal . . 5-31

Disassembly and Assembly See Overhaul Manual

Installation . . . . 5-31

GENERAL DESCRIPTION

The Power Brake Unit is a self-contained hydraulic

and vacuum unit, utilizing manifold vacuum and atmos-

phere pressure for its power.

This unit permits the use of a low brake pedal as well

as less pedal effort than is required with the conventional

(nonpower) hydraulic brake system. Only two external
line connections are necessary -
one
a vacuum connection

from manifold to check valve located on front shell; the

other, a hydraulic connection from the main cylinder

outlet directly into the hydraulic system. The unit is

mounted on the engine side of the fire wall and directly

connected to the brake pedal.

MAINTENANCE AND ADJUSTMENTS

INSPECTIONS

1.
Check vacuum line and vacuum line connections as

well as vacuum check valve in front shell of power

unit for possible vacuum loss.

2.
Inspect all hydraulic lines and connections at the

wheel cylinders and main cylinder for possible

hydraulic leaks.

3.
Check brake assemblies for scored drums, grease

or brake fluid on linings, worn or glazed linings,

and make necessary adjustments.

4.
Check brake fluid level in the hydraulic reser-

voirs.
The reservoirs should be filled to the levels

shown in Figure 8.

5. Check for loose mounting bolts at main cylinder and

at power section.

6. Check air cleaner filter in power piston extension

and replace filter if necessary.

7. Check brake pedal for binding and misalignment

between pedal
-and
push rod.

LUBRICATION

The power brake unit is lubricated at assembly and
needs no further lubrication other than maintaining

normal reservoir fluid level. The reservoir should be

filled as described in this section.

BLEEDING INSTRUCTIONS

The power system may be bled manually or with a

pressure bleeder as outlined in this section. Use only

GM
Supreme 11 Brake Fluid or equivalent. Do not use the

power assist while bleeding. The engine should not be

running and the vacuum reserve should be reduced to

zero by applying the brake several times before starting

the bleeding procedure.

AIR CLEANER SERVICE

Servicing of the air cleaner is recommended and the

element replaced when restriction becomes severe

enough to affect power brake response. At any other

time, if cleaning of the filter is felt necessary, it should

be shaken free of dirt or washed in soap and water and

thoroughly dried.

COMPONENT REPLACEMENT

POWER BRAKE CYLINDER

Removal

1.
Remove vacuum hose from vacuum check valve.

2.
Disconnect hydraulic lines at main cylinder.

Disconnect push rod at brake pedal assembly.

Remove nuts and lock washers securing power unit

to fire wall, and remove power unit from engine

compartment.
3.

4.

NOTE:
Chevy

to fire wall.
has a three stud attachment

Repair procedures for the power cylinder are outlined

in the Brake Section of the Overhaul Manual-for service
of the main cylinder refer to applicable portion of

"Standard Brakes" in this manual.

Installation

1.
Mount the power brake assembly in place and install

the attaching nuts and lock washers.

2.
Attach vacuum line to check valve.

3.
Secure hydraulic lines to main cylinder.

4.
Attach push rod to brake pedal assembly, and check

operation of stop light.

5. Bleed brakes as outlined in this section.

CAUTION: After replacing the unit on the vehi-

cle,
start the engine and allow vacuum to build

up before applying the brake.

CHEVROLET CHASSIS SERVICE

ENGINE
6-8

Check
and
Adjust Ignition Timing
(Fig. 13)

1.
Disconnect
the
distributor spark advance hose
and

plug
the
vacuum source opening.

2.
Start engine
and run at
idle speed
(see
tune
up
chart).

3.
Aim
timing light
at
timing
tab.

NOTE:
- The
markings
on the
tabs
are in 2°

increments
(the
greatest number
of
markings
on

the
"A"
side
of the "O"). the "O"
markings
is

TDC
of
#1 cylinder
and all
BTDC settings fall
on

the
"A"
(advance) side
of "O".

4.
Adjust
the
timing
by
loosening
the
distributor clamp

and
,
rotating
the
distributor body
as
required, then

tighten
the
clamp.

5.
Stop engine
and
remove timing light
and
reconnect

the spark advance hose.

Adjust Idle Speed
and
Mixture
(Fig. 14)
(Except when

equipped with
Air
Injection Reactor System)

1.
As a
preliminary adjustment, turn idle mixture

screws lightly
to
seat
and
back
out 2
turns.

CAUTION:
Do not
turn idle mixture screw

tightly against seat
or
damage
may
result.

2.
With engine running
at
operating temperature (choke

wide open) adjust idle speed screw
to
bring idle

speed
to
specified
rpm
(automatic transmission
in
drive, manual transmission
in
neutral).

3.
Adjust idle mixture screw
to
obtain highest steady

idle speed
(1/4
turn
out
from lean roll).

4.
Repeat Steps
2 and 3 as
needed
for
final adjustment.

5.
Shut down
the
engine, remove gauges
and
install
air

cleaner.

Adjust Idle Speed
and
Mixture
(Fig. 14)
(With
Air

Injection Reactor System)

The recommended adjustment procedure
for Air
Injec-

tion Reactor System equipped engines
is as
follows:

1.
As a
preliminary adjustment, turn idle mixture

screws lightly
to
seat
and
than back
out 3
turns.

CAUTION:
Do not
turn idle mixture screw

tightly against seat
or
damage
may
result.

2.
With engine running
at
operating temperature, choke

wide open,
and
parking brake applied, adjust idle

specified idle speed (automatic

"drive"-manual transmission
in
to

in
screw

transmission

"neutral").

;3.
Adjust idle mixture screw (turn
in) to
"lean roll"

position; then turn screw
out 1/4
turn
(1/4
turn rich

from "lean roll").
The
definition
of
"lean roll" point

is
a 20 to 30 rpm
drop
in
engine speed, obtained
by

leaning
the
idle mixture.

4.
Repeat Steps
2 and 3 as
needed
for
final adjustments.

ADDITIONAL CHECKS
AND
ADJUSTMENTS

Testing Crankcase Ventilation Valve
(Fig. 15) 0

1.
Connect tachometer
and
vacuum gauge
as for
idle

speed
and
mixture adjustment.

2.
Set
parking brake, start engine
and
adjust idle speed

and mixture.

3.
Disconnect ventilation hose
at
valve, block opening
of

valve
and
read engine
rpm
change.

4.
A
change
of
less than
50 rpm
indicates
a
plugged

ventilation valve
-
replace
the
valve.

Cylinder Balance Test
(Fig. 16)

It
is
often difficult
to
locate
a
weak cylinder.
A com-

pression test,
for
example, will
not
locate
a
leaky intake

manifold,
a
valve
not
opening properly
due to a
worn

camshaft,
or a
defective spark plug.

With
the
cylinder balance test,
the
power output
of one

cylinder
may be
checked against another, using
a set of

grounding leads. When
the
power output
of
each cylinder

is
not
equal,
the
engine will lose power
and run
roughly.

Perform
a
cylinder balance test
as
follows:

1.
Connect
the
tachometer
and
vacuum gauge.

2.
Start engine
and run at 1500 rpm.

3.
Ground large clip
of
grounding leads
and
connect
in-

dividual leads
to all
spark plugs except
the
pair being

tested.

Divide
the
firing order
in
half
and
arrange
one
half

over
the
other.
The
cylinders
to be
tested together
ap-

pear
one
over
the
other.

L4 Firing Order
V8 Firing Order

1-8-4-3-6-5-7-2

1-6, 8-5, 4-7, 3-2

1-3-4-2
= 1-3

4-2

L6 Firing Order

1-5-3-6-2-4
=
=
1-4. 3-2

1-5-3

6-2-4
1-6, 5-2, 3-4
1-8-4-3

6-5-7-2

4.
Operate engine
on
each pair
of
cylinders
in
turn
and

note engine
rpm and
manifold vacuum
for
each pair.

A variation
of
more than
1
inch
of
vacuum
or 40 rpm

between pairs
of
cylinders being tested indicates that

the cylinders
are off
balance.

Battery

The battery should
be
checked with special testing

equipment
and to the
equipment manufacturers specifica-

tions.
See
Section 6Y
for
complete information
on
battery

tests.

Ignition

The following additional ignition checks
may be
made

with
any of
several pieces
of
equipment available
for un-

covering
the
source
of
engine difficulties.
The
specific

operating instructions
of the
equipment manufacturer

should
be
followed:

Cranking voltage

Ignition switch

Distributor resistance

Secondary resistance

Ignition output
and
secondary leakage

Cranking Voltage
(Fig. 17)

1.
Disconnect coil primary lead
at the
coil negative

terminal
to
prevent engine from firing during

cranking.

2.
Connect voltmeter between primary terminal
of coi|

(resistance wire side)
and
ground.

3.
Operate starting motor.

CHEVROLET CHASSIS SERVICE MANUAL

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