Chevrolet 70 Series 1970, Service Manual

Page: 48 / 841

CAB AND BODY MOUNTINGS 1-17
P)
I ,
m - i
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8 NOTE: Ratchet p a w l spring removed in above view
1 C oil T erm in a ls
2. Solenoid Plunger
3 A ctuator P la te Tang
4 Cam F ollow er Upper Pin
5 R atchet Paw l
6
Cam F ollow er L ow er Pin
7 R atchet W heel
8
V alve A s s y . Mtg. S crew s
9 V alve A ssem b ly
10 R atchet Dog
11 Dog R etaining Screw
12 S olenoid C oil A sse m b ly
13 P iv o t P in
14 P isto n A ctuator P la te
15 R atchet W heel Spring
16 R atchet P aw l Spring
Figure 21—Washer Pump Mechanism
PUMP DISASSEMBLY AND ASSEMBLY
(R efer to F ig . 21)
1. Rem ove w asher pump cover.
2. Rem ove ratchet dog retaining sc r e w . Hold
sp rin g loaded solen oid plunger in p osition and
carefu lly lift the so len o id a ssem b ly and ratchet
dog off the fram e of the pump.
3. D isconnect ratchet pawl spring. R em ove
ratchet pawl retaining ring and slid e ratchet pawl
off cam follow er shaft.
4. Move ratchet w heel spring out of shaft
groove and slid e ratchet w heel off shaft.
5. P u ll pump housing away from fram e until
housing grooves clea r fram e. R em ove actuator
p late from ratchet w heel and cam follow er sh afts.
6
. R em ove sc r e w s that attach valve assem b ly
to pump housing. Separate valve assem b ly from
pump housing.
NOTE: O bserve direction of p ipes b efore r e ­
m oving pipe a ssem b ly from pump housing.
7. To a sse m b le , r e v e r s e "R em oval"procedure
NOTE: During r e a sse m b ly , be su re gask et b e ­
tween housing and valve p late is properly p o sitio n ­
ed in the housing and valve p la te g ro o v es. A lso , be
su re trip le O -rin g is properly in sta lled between
valve body and pipe a ssem b ly . H ose connections
on pipe a ssem b ly should be pointed in sam e d ir e c ­
tion a s origin al p osition.
AIR-OPERATED WINDSHIELD WIPERS
(SERIES 90 CON VENTIONAL CAB)
Dual air-o p era ted m otors are used on a ll
S e r ie s 90 conventional cab m odels. Figure 22
illu str a te s dual w iper m otors with th eir r e sp ectiv e
linkage. The left w iper m otor is equipped with a
sp eed control device (fig. 23) which can be adjusted
to balance the w iper sp eed of m otors.
The sy ste m a ir p r e s s u r e is supplied through
a protection valve which is mounted at the brake
s y s te m foot application valve. This valve autom at­
ic a lly shuts off the a ir p r e ssu r e to w iper sy ste m
in the event brake sy ste m p r e s s u r e drops below
60 to 70 p s i. M aintenance inform ation on valve is
covered in "AIR BRAKES" (SEC. 5B) of th is manual.
P er io d ic se r v ic in g is not required other than
m aking su re that a ll mounting parts are tight and
that a ir lin e s and line connections a re leak -p roof.
If inspection in d icates a faulty w iper m otor
unit, the unit can be readily rem oved from v eh icle,
d isa sse m b le d and rep aired . For rep air inform ation
s e e "Wiper Motor Repair" la ter in th is sectio n .
SERVICING
MOTOR BALANCING SPEED ADJUSTMENT
(R efer to F ig . 23)
The sp eed of either the right o r left w iper
m otor can be regulated by adjusting the balancing
valve which is located at the le ft w iper m otor.
W hile making adjustm ent, v e h ic le 's a ir p r e ssu r e
should be 85-100 p s i. Make adjustm ent a s follow s:
1. Wet the w indshield, then sta rt w ip ers in
m otion.
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL