1967 CHEVROLET CAMARO maintenance

BRAKES 5-14

Fig.
23—Removing or Installing Cover Lower Mounting Screws
Fig.
24—Removing or Installing Trim Seal

8. Remove front cable from lever assembly using long

nose pliers as shown in Figure 25. Remove lever

from vehicle.

Installation

1.^
Install front cable in lever assembly using long

nose pliers as shown in Figure 25. Slide slack

cable through hole and place lever assembly in

position.

2.
Place forward mounting bracket in position and

secure plate and lever assembly to underbody with

four mounting bolts.

3.
Secure parking brake alarm switch to side of lever

assembly with washer and screw (fig. 24).

4.
Install trim seal on lever (fig. 24).

5. Insert the end of the trim seal into the slot in the

cover and slide the cover forward and down into

position.

6. Place the retainer in position. Secure retainer and

cover to underbody with six screws. It is necessary

to push the seat cushion down as shown in Figure 23

to gain access to the lower mounting screw hole on

each side.

7. Under vehicle, insert front cable stud through equal-

izer assembly and secure with nut.

8. Install return spring.

9. Adjust parking brake as outlined under Maintenance

and Adjustments in this section.

Front Cable

Removal

1.
Perform the complete parking brake lever removal

procedure above.

2.
Under vehicle, remove nut, washer, and bolt se-

. curing pulley to pulley bracket (fig. 22).

3.
Remove seal grommet from underbody cable hole.

4.
Pull front cable out of vehicle.

Installation

1.
Install seal grommet around front cable.

2.
Slide front cable into position through cable hole

and work seal grommet into installed position.

3.
Under vehicle, loop front cable around pulley wheel

and secure pulley wheel to bracket with bolt, washer,

and nut (fig..22).

4.
Perform the complete parking brake lever installa-

tion procedure above.
Removal

1.
Remove the cable clip retainers on the back side of

the frame rail from each of the rear brake cable

ends.

2.
Disconnect the cable at the rear wheel flange plate.

3.
Remove the cable ball out of the recess in .the brake

lever assembly clevis.

4.
Disconnect the cables at the equalizer connector and

remove the cables.

Installation

1.
Attach the rear cable balls on the rear cable ends

to the rear wheel recess in the brake lever assembly

clevis.

2.
Attach the cable assembly to the rear wheel flange

plate.

3.
Connect the cable assemblies along the frame rail

area.

4.
Insert the cable end through the equalizer and attach

to the equalizer connector.

5. Adjust as outlined under Maintenance and

Adjustments.

6. Lubricate the cables and all moving parts for

trouble-free operation—see Lubrication, Section 0.

Fig.
25—Removing or Installing Front Cable

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-17

mended shoe and lining assemblies. Otherwise,

serious fade or failure may occur.

1.
Inspect new linings and make certain there are no

nicks or burrs on bonding material on shoe edge

where contact is made with brake flange plate or

on any of the contact surfaces.

NOTE: Keep hands clean while handling brake

shoes.
Do not permit oil or grease to come in

contact with linings.

2.
If working on rear brakes, lubricate parking brake

cable.

3.
On rear brakes only, lubricate fulcrum end of park-

ing brake lever and the bolt with brake lube, then

attach lever to secondary shoe with bolt, spring

washer, lock washer and nut. Make sure that lever

moves freely.

4.
Before installation make certain the adjusting screw

is clean and lubricated properly.

NOTE: Loose adjustment may occur from an

adjusting screw that is not properly operating.

If the lubrication in the adjusting screw as-

sembly is contaminated or destroyed, the ad-

justing screw should be thoroughly cleaned and

lubricated.

5.
Connect brake shoes together with adjusting screw

spring, then place adjusting screw, socket and nut

in position.

CAUTION: Make sure the proper adjusting

screw is used ("L" for left side of vehicle,

"R"
for right side of vehicle). The star wheel

should only be installed with the star wheel

nearest to the secondary shoe and the adjusting

screw spring inserted to prevent interference

with the star wheel.
6. On rear wheels connect parking brake cable to lever.

7.
Secure the primary brake shoe (short lining—faces

forward) first with the hold-down pin and spring

using a pair of pliers. Engages shoes with the wheel

cylinder connecting links.

8. Install and secure the actuator assembly and second-

ary brake shoe with the hold-down pin and spring

using a pair of needle nose pliers. On rear wheels

position parking brake strut and strut spring.

9. Install guide plate over anchor pin.

10.
Install the wire link.

NOTE: Do not hook the wire link over the

anchor pin stud with the regular spring hook

tool. This may damage the cylinder boot seals.

Fasten the wire link to the actuator assembly ;

first, then place over the anchor pin stud by

hand while holding the adjuster assembly in the

full down position.

11.
Install actuator return spring.

NOTE: Do not pry actuator lever to install re-

turn spring. Ease it in place using the end of a

screw driver or other suitable flat tool.

12.
If old brake pull back (return) springs are nicked,

distorted or if strength is doubtful, install new

springs.

13.
Hook springs in shoes using Tool J-8049 by in-

stalling the primary spring from the shoe over the

anchor pin and then spring from secondary shoe

over the wire link end.

14.
Pry shoes away from backing plate and lubricate

shoe contact surfaces with a thin coating of brake

lube (fig. 29).

CAUTION:

facings.
Be careful to keep lubricant off

Fig.
29—Backing Plate Contact Surfaces
15.
After completing installation, make certain the actu-

ator lever functions easily by hand operating the

self-adjusting feature (fig. 30).

1.6. Follow the above procedure for all wheels.

17.
Adjust the service brakes and parking brake as

outlined under "Maintenance and Adjustments" in

this section.

Metallic Linings

Metallic brake linings which use special heat resistant

brake springs are available as an option. Service opera-

tions are the same as for standard brakes; however,

when new linings are installed, the linings should be

seated as described below.

NOTE: Brake shoes with metallic linings re-

quire specially finished brake drums (honed to a

20 micro-inch finish). Metallic linings are not

recommended for service replacement on ve-

hicles with standard brake drums that have not

been honed to specified finish.

Seating Metallic Linings

After the brakes have been adjusted, the following

recommended "lining seating" is as follows:

1.
Make six to eight stops from 30 MPH with moderate

pedal pressure to aid in seating and to mbdulate

any tendency to dive.

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 5-29

Fig.
42—Installing Caliper on Disc

Check that the hose does not touch other parts at

any time during suspension or geometry travel.

If contact does occur, remove the U-shaped retainer

and rotate the end of the hose in the support bracket

one or two points in a direction which will eliminate

hose contact. Reinstall the retainer and recheck

for hose contact. If it is satisfactory, place the

steel tube connector in the hose fitting and tighten

securely.

If rear brake caliper is being serviced, connect

brake line to caliper.

Bleed brakes as outlined in this section.

Install wheels and lower vehicle.

BRAKE DISC

Servicing of the disc brakes is extremely critical

due to tolerances required in machining of the brake

disc to insure proper brake operation. In manufacturing

the brake disc, tolerances of the rubbing surfaces for

flatness is .001 and for parallelism is .0005, while

lateral runout of the faces must not exceed .004 total.

The maintenance of these close controls of the shape of

the rubbing surfaces is necessary to prevent brake

roughness. In addition, the surface finish must be non-

directional and maintained at 30-50 micro-inches. This

control of the rubbing surface finish is necessary to

avoid pulls and erratic performance and promote long

lining life and equal lining wear of both left and right

brakes.

tight scoring of the disc surfaces not exceeding .015

in depth, which may result from normal use, is not

detrimental to brake operation.

When the total disc thickness is less than .965 for the

1"
thick disc or 1.215 for the 1-1/4" thick disc, it should

be replaced. Disc thicknesses less than this can permit

the shoes to come out of contact with the shoe abutments

and cause malfunction.

Because performance is not impaired by surface im-

perfection not exceeding .015 deep, refinishing of the

rubbing surface is not necessary.
Fig.
43—Dial Indicating Disc Runout

Since extremely accurate control of the finishing oper-

ation is necessary for proper performance and excess

metal removal can cause malfunction, refinishing of the

rubbing surface is not recommended.

Checking Procedure (Fig. 43)

Front

Tighten the adjusting nut of the wheel bearing until all

play has been removed. It should be just loose enough

to allow the wheel to turn. Clamp a dial indicator to the

caliper so that its button contacts the disc at a point about

1 inch from the outer edge. When the disc is turned, the

indicator reading should not exceed .002 inches. If runout

exceeds this amount the hub and disc assembly should

be replaced. Due to the close tolerances involved it is

not recommended that the front discs be machined or

serviced separately.

After checking the runout, readjust, the wheel bearings

as outlined in Section 3 of this manual.

Rear—Corvette Only

Check the rear wheel bearing end play, as outlined in

Section 4 of this manual. Then dial indicate the disc face.

If lateral runout of the disc exceeds the bearing end play

by .003 inches, the disc should be refaced (not to exceed

.040 inches) or replaced.

Removal

1.
Raise vehicle and remove wheel and tire assembly.

/ 2. Remove brake caliper as outlined in this section.

3.
Drill out the five rivets attaching the disc to the hub

or spindle.

4.
Remove brake disc from vehicle.

5. Complete the removal of the five rivets from the

hub or spindle.

Installation

1.
Install the disc to the hub or spindle aligning the lug

bolts with the holes in the disc.

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
6-3

(ROUND) Y~~fll^H

CENTRIFUGAL
A ^k

ADVANCE--jflgKpl

MECHANISM
UB|

CAM
KSK^2

LUBRICATOR
VlSMi

REPLACEMENT
^BK

-^ADJUST
SQUARELY

AND
JUST

TOUCHING
LOBE

OF
CAM
/ROTOR

HBB
__

I^BH^F
?
(SOUARE)

^K^ I /—
CAM

jKft^J / LUBRICATOR

H^T^
CAUTION!

QV NEVER
OIL

•L-^
CAM LUBRICATOR-

REPLACE
WICK

WHEN
NECESSARY
LATERAL

MISALIGNMENT
PROPER

LATERAL ALIGNMENT

Fig.
4- Distributor (V8)

CAUTION: Use extreme care
-when
using tap to

prevent cross threading. Also crank engine sev-

eral times to blow out any material dislodged

during cleaning operation.

7. Install spark plugs with new gaskets and torque to

specifications.

NOTE:
The following are some of the

greatest causes of unsatisfactory spark plug

performance.

•
Installation of plugs with insufficient torque to

fully seat the gasket.

•
Installation of the plugs using excessive torque

which changes gap settings.

•
Installation of plugs on dirty gasket seal.

•
Installation of plugs into corroded spark plug hole

threads.

8^ Connect spark plug wiring.

Service
Ignition System

1.
Remove distributor cap, clean cap and inspect for

cracks, carbon tracks and burned or corroded ter-

minals. Replace cap where necessary.

2.
Clean rotor and inspect for damage or deterioration.

Replace rotor where necessary.

3.
Replace brittle, oil soaked or damaged spark plug

wires.
Install all wires to proper spark plug. Proper

positioning of spark plug wires in supports is impor-

tant to prevent cross-firing.

4.
Tighten all ignition system connections.

5. Replace or repair any wires that are frayed, loose or

damaged.
Us
CORRECT
LATERAL MISALIGNMENT BY

j BENDING
FIXED CONTACT SUPPORT

[NEVER
BEND BREAKER LEVER

Fig.
5 - Point Alignment

Magnetic
Pulse(Breakerless)
Distributor

There are no moving parts in the ignition pulse ampli-

fier, and the distributor shaft and bushings have perma-

nent type lubrication, therefore no periodic maintenance

is required for the magnetic pulse ignition system. Refer

to Section 6Y for an analysis of problems and/or repair

procedures encountered on the Transistorized (Magnetic

Pulse) ignition system.

Standard
(Breaker Point) Distributor
(Figs.
3 or 4)

1.
Check the distributor centrifugal advance mechanism

by turning the distributor rotor in a clockwise direc-

tion as far as possible, then releasing the rotor to

see if the springs return it to its retarded position.

If the rotor does not return readily, the distributor

must be disassembled and the cause of the trouble

corrected.

2.
Check to see that the vacuum spark control operates

freely by turning the movable breaker plate counter-

clockwise to see if the spring returns to its retarded

position. Any stiffness in the operation of the spark

control will affect the ignition timing. Correct any

interference or binding condition noted.

3.
Examine distributor points and clean or replace if

riecessary.

DO
NOT SUCK

IN
TOO MUCH

ELECTROLYTE

TAKE
READING

AT
EYE LEVEL

Fig.
6 - Testing Specific Gravity of Battery

CHEVROtET
CHASSIS SERVICE MANUAL

SECTION 6K

ENGINE COOLING

INDEX

Page

General Description . . . 6K-1

Maintenance and Adjustments 6K-1

Coolant Level 6K-1

Coolant System Checks 6K-1

Periodic Maintenance 6K-2

Cleaning 6K-2

Reverse Flushing 6K-2

Radiator 6K-2
Page

Cylinder Block and Cylinder Head 6K-2

Hot Water Heater 6K-2

Fan Belt . 6K-2

Adjustment ....". 6K-2

Thermostat . 6K-2

Replacement 6K-2

Water Pump. . . . 6K-3

Removal 6K-3

Installation 6K-3

GENERAL DESCRIPTION

A pressure cooling system is provided for on all

models by a pressure type radiator cap (fig. 1). The

pressure type radiator cap used is designed to hold a

pressure above atmospheric pressure in the cooling

system. Excessive pressure is relieved by a valve within

the cap that opens to radiator overflow.

The water pump is a ball bearing, centrifugal vane

impeller type. It requires no care other than to make

certain the air vent at the top of the housing and the drain

holes in the bottom do not become plugged with dirt or

grease. Removal and installation of the water pump is

covered in this section. For overhaul procedures of the

water pump refer to Section 6K of the Passenger Chassis

Overhaul Manual.
For radiator, refer to Section 13 of this manual For

radiator shroud, refer to Section 11 of this manual.

Fig.
I—Pressure Radiator Cap

MAINTENANCE AND ADJUSTMENTS

Coolant Level

The radiator coolant level should only be checked when

the engine is cool, particularly on cars equipped with air

conditioning. If the radiator cap is removed from a hot

cooling system, serious personal injury may result

The cooling system fluid level should be maintained

one inch below the bottom of the filler neck of the radia-

tor when cooling system is cold, or at the bottom of the

filler neck when the system is warm. It is very impor-

tant that the correct fluid level be maintained. The seal-

ing ability of the radiator cap is affected when the cooling

level is too high.

All passenger car cooling systems are pressurized

with a pressure cap which permits safe engine operation

at cooling temperatures of
up
to 247°F.

When the radiator cap is removed or loosened, the

system pressure drops to atmospheric, and the heat

which had caused water temperature to be higher than

212°F, will be dissipated by conversion of water to

steam. Inasmuch as the steam may form in the engine

water passages, it will blow coolant out of the radiator

upper hose and top tank, necessitating coolant replace-

ment Engine operating temperatures higher than the

normal boiling point of water are in no way objectionable

so long as the coolant level is satisfactory when the

engine is cooL

Upon repeated coolant loss, the pressure radiator cap

and seat should be checked for sealing ability. Also, the
cooling system should be checked for loose hose con-

nections, defective hoses, gasket leaks, etc.

Coolant System Checks

1.
Test for restriction in the radiator, by warming the

engine up and then turning the engine off and feeling

the radiator. The radiator should be hot at the top

and warm at the bottom, with an even temperature

rise from bottom to top. Cold spots in the radiator

indicate clogged sections.

2.
Water pump operation may be checked by running the

engine while squeezing the upper radiator hose. A

pressure surge should be felt Check for a plugged

vent-hole in pump.

NOTE:
A defective head gasket may allow ex-

haust gases to leak into the cooling system.

This is particularly damaging to the cooling

system as the gases combine with the water to

form acids which are particularly harmful to

the radiator and engine.

3.
To check for exhaust leaks into the cooling system,

drain the system until the water level stands just

above the top of the cylinder head, then disconnect

the upper radiator hose and remove the thermostat

and fan belt. Start the engine and quickly accelerate

several times. At the same time note any appreci-

able water rise or the appearance of bubbles which

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE COOLING 6K-2

are indicative of exhaust gases leaking into the coolr

ing system.

Periodic Maintenance

Periodic service must be performed to the engine cool-

ing system to keep it in efficient operating condition.

These services should include a complete cleaning and

reverse flushing as well as a reconditioning service.

In the course of engine operation, rust and scale ac-

cumulate in the radiator and engine water jacket. The

accumulation of these deposits can be kept to a minimum

by the use of a good rust inhibitor but it should be

remembered that an inhibitor will not remove rust al-

ready present in the cooling system.

Two common causes of corrosion are: (1) air suction--

Air may be drawn into the system due to low liquid level

in the radiator, leaky water pump or loose hose con-

nections; (2) exhaust gas leakage—Exhaust gas may be

blown into the cooling system past the cylinder head

gasket or through cracks in the cylinder head and block.

Cleaning

A good cleaning solution should be used to loosen the

rust and scale before reverse flushing the cooling

system. There are a number of cleaning solutions avail-

able and the manufacturer's instructions with the particu-

lar cleaner being used should always be followed.

An excellent preparation to use for this purpose is GM

Cooling System Cleaner. The following directions for

cleaning the system applies only when this type cleaner

is-used.

1.
Drain the cooling system including the cylinder block

and then close both drain plugs.

2.
Remove thermostat and replace thermostat housing.

3.
Add the liquid portion (No. 1) of the cooling system

cleaner.

4.
Fill the cooling system with water to a level of about

3 inches below the top of the overflow pipe.

5. Cover the radiator and run the engine at moderate

speed until engine coolant temperature reaches 180

degrees.

6. Remove cover from radiator and continue to run the

engine for 20 minutes. Avoid boiling.

7. While the engine is still running, add the powder

portion (No. 2) of the cooling system cleaner and

continue to run the engine for 10 minutes.

8. At the end of this time, stop the engine, wait a few

minutes and then open the drain cocks or remove

pipe plugs. Also remove lower hose connection.

CAUTION: Be careful not to scald your hands.

NOTE:
Dirt and bugs may be cleaned out of

the radiator air passages by blowing out with air

pressure from the back of the core.

Reverse Flushing

Reverse flushing should always be accomplished after

the system is thoroughly cleaned as outlined above.

Flushing is. accomplished through the system in a direc-

tion opposite to the normal flow. This action causes the

water to get behind the corrosion deposits and force

them out.

Radiator

1.
Remove the upper and lower radiator hoses and re-

place the radiator cap,

2.
Attach a lead-away hose at the top of the radiator.
3.
Attach a new piece of hose to the radiator outlet

connection and insert the flushing gun in this hose.

4.
Connect the water hose of the flushing gun to a water

outlet and the air hose to an air line.

5. Turn on the water and when the radiator is full, turn

on the air in short blasts, allowing the radiator to

fill between blasts of air.

CAUTION: Apply air gradually as a clogged

radiator will stand only a limited pressure.

6. Continue this flushing until the water from the lead-

away hose runs clear.

Cylinder Block and Cylinder Head

1.
With the thermostat removed, attach a lead-away

hose to the water pump inlet and a length of new hose

to the water outlet connection at the top of the engine.

NOTE:
Disconnect the heater hose when re-

verse flushing engine.

2.
Insert the flushing gun in the new hose.

3.
Turn on the water and when the engine water jacket

is full, turn on the air in short blasts.

4.
Continue this flushing until the water from the lead-

away hose runs clear.

Hot Water Heater

1.
Remove water outlet hose from heater core pipe.

2.
Remove inlet hose from engine connection.

3.
Insert flushing gun and flush heater core. Care must

be taken when applying air pressure to prevent

damage to the core.

Fan Belt

Adjustment

1.
Loosen bolts at Delcotron slotted bracket.

2.
Pull Delcotron away from engine until desired ten-

sion reading is obtained with a strand tension gauge.

Refer to Section 6, "Engine Tune-Up".

3.
Tighten all Delcotron bolts securely.

Thermostat

The thermostat consists of a restriction valve actuated

by a thermostatic element. This is mounted in the hous-

ing at the cylinder head water outlet above the water

pump,
thermostats are designed to open and close at

predetermined temperatures and if not operating properly

should be removed and tested as follows.

Replacement

1.
Remove radiator to water outlet hose.

2.
Remove thermostat housing bolts and remove water

outlet and gasket from thermostat housing (fig. 2).

3.
Inspect thermostat valve to make sure it is in good

condition.

4.
Place thermostat in hot water 25° above the temper-

ature stamped on the thermostat valve.

5. Submerge the valve completely and agitate the water

thoroughly. Under this condition the valve should

open fully.

6. Remove the thermostat and place in water 10° below

temperature indicated on the valve.

7. With valve completely submerged and water agitated

thoroughly, the valve should close completely.

8. If thermostat checks satisfactorily, re-install, using

a new housing gasket.

9. Refill cooling system.

CHEVROLET CHASSIS SERVICE MANUAL