Chevrolet 10 Series 1970 Service Manual page 635

Fig. 7 — Release S w itches and Brackets
R egu lator th ereby b leedin g down the Servo tow ard
the rela x ed position.
Engagem ent Switch, " p u ll- in " and " h o ld -in " o f the
solenoid occu rs, re s p e c tiv e ly .
engaged to maintain the ca r speed at the tim e o f
Engagem ent Switch re le a s e .
9. D r iv e r d e s ir e s lo w e r cru isin g speed, p re s s e s En­
gagem ent Switch fu lly, w aits until ca r speed de­
The components of the C ru ise M a s te r system a re de­
signed to be rep la ced should they becom e in op erative.
The R egu lator is calib ra ted in such a manner during
m anufacturing that overhaul operations a re im p ra ctica l.
H o w ever, one adjustment m ay be made to the R egu lator
to c o r r e c t speed drop
engagem ent.
BRAKE. RELEASE SWITCHES
ELECTRIC
Service—
An in op erative
Switch replacem en t is identical to standard brake lam p
sw itch replacem en t.
A djustm ent—
The brake o r clutch sw itch plunger must
c le a r the pedal arm when the arm
m easu red at the switch (fig . 7).
V A C U U M
Service
— An in op erative (stick in g, plugged, o r leaking)
sw itch must be rep laced .
to brake sw itch replacem ent.
the sw itch is connected fir m ly
d e te rio ra te d .
A djustm ent
— The brake switch plunger must c le a r the
p edal arm when the arm is m oved 5/16 inch m easured at
the sw itch (fig. 7).
A s the d r iv e r re le a s e s the
The system is now
SERVICE OPERATIONS
o r in crease at the tim e o f
sw itch must be rep laced.
is m oved 1/4 inch
Switch rep lacem en t is s im ila r
Be certa in that the hose to
and is not cracked or
cre a s e s to d e sire d speed then r e le a s e s Sw itch--w hen
the Engagem ent sw itch is fu lly d ep ressed the s o le ­
noid is d e -e n e rg iz e d causing the vacuum sw itch to
b leed down the Servo to idle throttle position and the
" U " clip o f the a ir bleed va lve is re lea se d fro m the
rubber drum. The drum and d isc assem b ly is fre e
to rotate to a position which corresp on ds to veh icle
speed as the ca r slow s. When the d r iv e r re le a s e s
the Engagem ent Switch,
" h o ld s -in " in the norm al manner.
va lve is clutched to the rubber drum at the c a r speed
correspon din g to switch re le a s e . Vacuum is again
applied to the " T e e " fittin g and th rottle con trol is
assum ed by the R egu lator to maintain the c a r speed
at the tim e o f switch re lea se .
10. W ith system in operation, d r iv e r applies b ra k e s --
sim ulataneously the Vacuum R e le a se and E le c tr ic
R e le a s e Switches operate. The Vacuum Switch bleed s
a ir into the Servo.
S ervo and the th rottle returns to idle position. The
E le c tr ic R e le a se Switch cuts o ff pow er to the en tire
system and the solen oid is d e-e n erg ized .
d r iv e r re m o v e s his foot fro m the brake pedal the
E le c tr ic Switch again fee d s voltage to the Engagem ent
Switch and the Vacuum Switch seals the a ir b leed
line. The unit w ill not re -en g a g e since it r e c e iv e s
only a sm all cu rrent through the 40 ohm resistan ce
w ire . I f v eh ic le speed is below 30 M PH the system
may not be re-en g a g ed since the tang on the rubber
drum has opened the low lim it switch points in the
Regu lator.
ENG AG EM ENT SWITCH
SERVICE
The e n g a g e m e n t
replacem en t.
Rem oval
1. D isconnect b a ttery ground cable.
2. P r y the engagem ent button out o f the turn signal
knob with a sm a ll thin bladed s c r e w d r iv e r .
3. With a sm all hook o r long nosed p lie r s , rem ove the
switch retain in g ring.
4. R em ove stee rin g w heel to gain a c cess to turn signal
le v e r attaching screw .
signal le v e r fro m turn signal housing u tilizin g the
slack in the w irin g harness.
5. Push slack into turn signal le v e r
le v e r (attachment end). T h is w ill fo r c e switch out of
the other end o f the le v e r .
6. W ith a sm all so ld erin g iron, unsolder the w ire s and
r e s o ld e r them to the c o r r e c t term in a l o f the r e ­
placem ent switch. U se only rosin core sold er.
Installation
1. Once a new switch is in stalled, pull it back into the
le v e r by pulling on the harness at the le v e r slot.
2. R ein sta ll retaining rin g and button.
3. Push w ire slack into turn signal housing; rein sta ll
turn signal le v e r and ste erin g wheel.
4. Connect battery ground cable.
ACCESSORIES 15-5
the unit " pulls in "
The a ir bleed
The vacuum is reduced in the
I f the
is s e rv ic e d only
R em ove screw . Rem ove turn
slo t at base o f
CHEVROLET TRUCK SERVICE MANUAL
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