Chevrolet 10 Series 1970, Service Manual

Page: 636 / 671

ACCESSORIES 15-6
CONTROL VALVE
CLUTCH SPRING
LOCKNUT
ORIFICE TUBE &
DNNECTOR ASSEMBLY
SIDE VIEW SECTION
ENGINE V A C U U M
CONNECTOR
V A C U U M VALVE
LO CK-IN C A M
SOLENOID PLUNGER
AIR FILTER
END VIEW SECTION
M AG NET
SPEED DISC
FIELD PLATE
HAIRSPRING
SOLENOID & CLUTCH
H O U S IN G ASSEMBLY
SPEED SWITCH
M A G N ET H O U S IN G
ASSEMBLY
FROM
TRANSM ISSION
SOLENOID COIL
TO SPEEDOMETER
F ig . 8 — R egu lator - Cross S e c tio n
SERVO
SERVICE
— If the S ervo unit is found to be d efe c tiv e , r e ­
placem ent is req u ired . N ote the condition o f the hoses
and rep lace any which a re cracked o r d eteriora ted .
ADJUSTMENT
— ust the bead chain so that it is as tight
as p ossib le without holding the th rottle open when the
ca rb u retor is set at its low est idle th rottle position.
When connecting the bead chain (engine stopped) manually
set the fast id le cam at its low est step and connect the
chain so that it does not hold the idle screw o ff the cam.
If the chain needs to be cut, cut it three beads beyond the
bead which pulls the linkage.
REGULATOR
M A IN T E N A N C E
A d e fe c tiv e regu lator, that is one which
is not sim ply out o f adjustment, must be replaced. D ur­
ing replacem en t, check the hoses which connect to
the regu la tor and rep la ce any which a re cracked o r
d eterio ra ted .
ADJUSTMENT
One regu la tor adjustment is possib le: Engagem ent-
C ru isin g Speed Z e ro in g (to rem o ve any d ifferen ce b e ­
tween engagement and cru isin g speed).
NOTE: No regu la to r adjustment should be
made, h ow ever, until the follow in g item s have
been checked o r se rv ic e d .
1. Bead chain p ro p e rly adjusted.
2. A ll hoses in good condition, p ro p e rly attached, not
leaking, not pinched o r kinked.
3. E le c tr ic and vacuum re le a s e sw itches p ro p e rly
adjusted.
E N G A G E M E N T -C R U IS IN G SPEED ZER O IN G
I f the cru isin g speed is lo w e r than the engagem ent
speed, loosen the o r ific e tube locknut (see fig . 8) and
turn the tube outward; if higher, turn the tube inward.
Each 1/4 turn w ill a lte r the en gagem en t-cru isin g speed
d iffe re n c e one mph. Tighten the locknut a fte r adjustment
and check the system operation at 60 M PH .
ELECTRICAL SYSTEM CHECK OUT
1. Check fuse and connector.
2. Check e le c tr ic brake switch as fo llo w s: Unplug con­
n ector at switch. Connect ohm m eter at points A and
B on brake switch. The oh m m eter must indicate in­
fin ity when the pedal is d ep ressed and continuity
when pedal is relea sed . The cru ise re le a s e brake
switch (e le c tr ic ) is adjusted as is the standard stop
light brake switch. R eplace e le c t r ic brake switch if
needed.
3. Check engagem ent switch and connecting w irin g as
follow s: Unplug engagement sw itch connector (brown,
blue, black) at e le c tr ic a l w irin g harness connector
and p e rfo rm the fo llo w in g tests. (See fig . 9).
T e s t #1 - Connect ohm m eter between term in a l #1
(brown w ir e ) and term in a l #2 (blue w ir e ). Continuity
shall be maintained until sw itch is d ep ressed a ll the
way in.
T e s t #2 - Connect oh m m eter between term in al #1
CHEVROLET TRUCK SERVICE MANUAL