
BUMPERS 14-2
placed in the tab of each bumper bracket. Dial the
adjustment washers in the tabs as required to posi-
tion the bumper at the correct mounted height
3.
Tighten all bolts securely, connect parking lamp wir-
ing, and lower vehicle.
REAR BUMPER ASSEMBLY (Fig. 2)
Removal
1.
Raise and support rear end of vehicle.
2.
Disconnect rear license plate lamp wiring.
3.
On Caprice models, disconnect back-up lamp wiring.
4.
Remove center face bar to frame attaching bolts lo-
cated behind license plate door.
5. Remove bolts from each side "attaching bumper
brackets and braces to frame.
6. Remove bumper from vehicle.
Fig.
1 -
Front Bumper Assembly
-
Chevrolet
FILLER
STAPLE
VIEW
B \ ^7 ^^ B
ALL EXCEPT STATION WAGON
Fig. 2 - Rear Bumper Assembly - Chevrolet
Disassembly
1.
Remove license plate lamp.
2.
On Caprice models, remove
assemblies.
Remove bolts
3.
back-up lamp
each bumper brace to
retaining
bumper.
4.
Remove bolts retaining each bumper bracket to
bumper and separate sections of face bar at joints.
5.
The license plate door (sedan models) and bumper
pads (station wagon models) may be removed by re-
moving the attaching parts shown in Figure 2.
Assembly
On Caprice models, attach both back-up lamps to cen-
ter face bar and tighten bolts firmly. Assemble the rear
bumper following the disassembly procedure in reverse
order. Except for back-up lamp attachments on Caprice
models, install all bolts loosely; do not tighten any bolts
until all bolts are installed.
Installation
1.
Position bumper assembly on vehicle aligning holes
in braces and mounting brackets with those in frame,
2.
Loosely install bolts, lock washers, and nuts includ-
ing center face bar to frame bolts behind license
plate door. Note that eight sided adjustment washers
(fig. 2) are placed in the tab of each bumper mounting
bracket. Dial the adjustment washers in the tabs as
CHEVROLET CHASSIS SERVICE MANUAL

BUMPERS 14-3
required to position the bumper at the correct
mounted height. ,
3.
Tighten all mounting bolts securely and connect li-
cense plate lamp wiring. On Caprice models, con-
nect back-up lamp wiring. Lower vehicle.
GENERAL DESCRIPTION-CHEVELLE
The new front bumper is of a one piece design with the
parking and turn signal lamp assemblies attached to each
outboard end of the bumper.
The rear bumper is also of a one piece design with
provisions for rear gas fill. The back-up lamp assem-
blies are attached near the center of the bumper.
SERVICE OPERATIONS
FRONT BUMPER ASSEMBLY
Removal
1.
Raise and support front of vehicle.
2.
Disconnect parking lamp wiring. -
Fig.
3 - Front Bumper Assembly - Chevelle
Disassembly
1.
Remove bolts attaching braces and brackets to
bumper.
2.
Remove bolts from each parking lamp assembly and
remove parking lamps from bumper.
Assembly
Attach both parking brake lamp assemblies to front
bumper and tighten bolts firmly. Assemble the front
bumper parts by following the disassembly procedure in
reverse order. Except for the parking lamp attachments,
install all bolts loosely; do not tighten any bolts until all
bolts are installed.
Installation
1.
Position the front bumper on the frame horns align-
ing holes in brackets and braces with those in the
frame.
2.
Loosely install bolts, lock washers, and nuts. Note
that eight sided adjustment washer (fig. 3) is placed
in the tab of each mounting bracket. Dial tjie adjust- .
ment washers in the tabs as required to position the
bumper at the correct mounted height.
3.
Tighten all mounting bolts securely, connect the
parking lamp wiring, and lower front of vehicle.
3.
Remove bolts retaining the bumper brackets and
braces to the frame.
4.
Remove bumper assembly from vehicle.
ADJUSTMENT
WASHER
Fig.
4-Rear Bumper Assembly - Chevelle
REAR BUMPER ASSEMBLY (Fig. 4)
Removal
1.
Raise rear end of vehicle.
2.
Disconnect rear license plate lamp and back-up lamp
wiring.
3.
Remove bolts, located behind license plate door, at-
taching face bar reinforcement to frame.
4.
Remove four bolts retaining bumper brackets and
braces to frame.
5. Remove bumper from vehicle.
Disassembly
1.
Remove license plate lamp and back-up lamps from
bumper.
2.
Remove brackets and braces at each end of bumper.
3.
Remove license plate door.
4.
Remove rivets attaching bracket at center of bumper.
Assembly
Attach license plate lamp and back-up lamp assemblies
to bumper; tighten bolts firmly. Assemble the bumper
parts by following the disassembly procedure in the re-
verse order. Except for the license plate lamp and back-
up lamp attachments, install all bolts loosely; do riot
CHEVROLET CHASSIS SERVICE MANUAL

BUMPERS 14-4
tighten any bolts until all bolts have been installed.
Installation
1.
Position bumper bracket and brace on the frame
aligning holes in frame with those in bracket and
brace.
2.
Loosely install bolts, lock washers and nuts. Note
that eight sided adjustment washers (fig. 4) are
placed at the inside surface of each rear frame
channel. Dial washers as required to position
bumper at correct height.
Tighten all mounting bolts securely, connect back-up
lamp and license plate lamp wiring, and lower rear
of vehicle.
GENERAL DESCRIPTION-CHEVY II
The front and rear bumpers are of a one piece design
with the parking and turn signal assemblies attached to
each outboard end of the front bumper.
SERVICE OPERATIONS
FRONT BUMPER ASSEMBLY (Fig. 5)
Removal
1.
Raise front end of vehicle.
2.
Disconnect parking lamp wiring.
3.
Remove bolts retaining bumper brackets and braces
to frame.
4.
Remove bumper assembly from vehicle.
Disassembly
1.
Remove bolts securing parking lamp assemblies and
remove parking lamps from vehicle.
2.
Remove bolts attaching braces and bumper brackets
to bumper face bar.
Assembly
Referring to Figure 5, assemble brackets and braces
and install parking lamps to face bar. Install all bolts
loosely—do not tighten any bolts until all bolts have been
installed.
Installation
1.
Position assembled bumper on frame extensions,
aligning holes in extension with holes in brackets and
braces.
2.
Install bolts, lock washers, and nuts; tighten
securely.
3.
Connect parking lamp wiring and lower front end of
vehicle.
REAR BUMPER ASSEMBLY (Fig. 6)
Removal
1.
Disconnect license plate lamp wire at connector.
2.
Raise vehicle from floor. From forward side and
underside of rear crossmember, remove mounting
bolts retaining the bumper brackets to the vehicle.
3.
Remove bumper assembly from vehicle.
Disassembly
1.
Remove license plate lamp.
2.
Remove, bolts attaching each bracket to bumper.
Check condition of seal; replace if necessary.
Assembly
1.
Position brackets on face bar as shown in Figure 6
and install mounting bolts; tighten nuts securely.
2.
Install license plate lamp.
Instalfation
1.
Position bumper assembly on vehicle, aligning tapped
holes in bracket with- slotted holes in rearward face
of rear crossmember and install bolts loosely.
2.
Align slotted hole in bracket with tapped hole in
lower flange of rear crossmember and install bolt
loosely.
3.
Adjust entire bumper assembly so that the distance
Fig.
5 - Front Bumper Assembly - Chevy
Fig.
6 - Rear Bumper Assembly - Chevy
CHEVROLET CHASSIS SERVICE MANUAL

BUMPERS 14-7
only and the distance between inner upper brace and
frame filled in with shims. Bolts may then be installed
to secure brace to frame.
REAR LICENSE PLATE HOUSING
The rear license plate housing may be removed from
the vehicle by removing the license plate and removing
the retaining screws as shown in Figure 9.
Fig.
9- Rear License Plate Housing
GENERAL DESCRIPTION-CAMARO
The Camaro front and rear bumpers are of a single
piece wrap around design. The front license plate bracket
functions as a bumper support between the valance panel
and bumper. Holes in the underside of bumpers, slightly
inboard of lower bumper bracket bolt, provide for new
jack load rest stud for jacking purposes.
SERVICE OPERATIONS
FRONT BUMPER ASSEMBLY (Fig. 10)
Removal
1.
Raise and support front end of vehicle.
2.
Remove bolts securing bumper support brackets to
frame.
3.
Remove bolts, one on each side at fender extension
panels, securing bumper to outer bumper bracket.
4.
Remove screws and nuts securing license plate
bracket to valance panel and remove bumper from
vehicle.
Disassembly
1.
Remove bolts attaching two support brackets to
bumper.
2.
Remove screw and nut securing license plate bracket
to bumper.
Assembly
Assemble the front bumper following the disassembly
procedure in reverse order. Install all bolts loosely; do
not tighten any bolts until all bolts are installed.
Installation
1.
Position assembled bumper on frame horns aligning
holes in bumper brackets with those in frame.
2.
Loosely install bolts, lock washers, and nuts. .Note
3.
the eight sided adjustment washers (fig. 10) are
placed in the tab of each bumper bracket. Dial the
adjustment washers in the tabs as required to posi-
tion the bumper at the correct mounted height.
Tighten all bolts securely and lower vehicle.
REAR BUMPER ASSEMBLY (Fig. 11)
Removal
1.
Raise and support rear end of vehicle.
2.
Remove bolts securing bumper brackets to frame
and rear fenders.
3.
Remove screws securing license plate bracket to
body and remove bumper from vehicle.
Disassembly
1.
Remove bolts securing four support brackets to
bumper.
2.
Remove rivets securing license plate bracket to
bumper.
Assembly
Assemble the rear bumper following the disassembly
procedure in reverse order. Install all bolts loosely; do
not tighten any bolts until all bolts are installed.
CHEVROLET CHASSIS SERVICE MANUAL

BUMPERS 14-8
Ifistaliotion
1.
Position assembled bumper on frame and body align-
ing holes in bumper brackets with those in frame.
2.
Loosely install all bolts, lock washers and nuts. In-
sure bumper is in correct mounted position.
3.
Tighten all bolts securely and lower vehicle.
Fig.
10 - Front Bumper Assembly - Camaro
Fig.
11 - Rear Bumper Assembly - Camaro
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

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