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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 r e -
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 A N D 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
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