Chevrolet DB90 Series, Руководство по обслуживанию

Страница: 21 / 242

Sec. 1-15
CAB AND BODY MOUNTINGS
AIR OPERATED WINDSHIELD WIPERS
DUAL WIPER CONTROL VALVES
A ll model v e h ic le s with a ir operated wind­
sh ield w ip ers are equipped with dual control valves
a s shown in sch em atic (fig. 5).
The control knob at left op erates left w iper
and control knob at right op erates right w iper.
To operate w ip ers, turn w iper control knobs
counterclockw ise toward run p osition . V ariable
speed air powered w iper m otors w ill operate w ip­
e r s . To stop w ip ers, turn knobs clock w ise to park
p o sitio n . If blades do not park properly m om entar­
ily , turn knob or knobs clo ck w ise against spring
tension beyond park position . B lades w ill park.
NOTE: Speed of the w iper m otors is controlled
by the control v a lv es.
To check control valve, connect a ir supply
lin e to "IN" port and turn control on. If air flows
from the "RUN" port only the control is operating
p roperly. If air flow s from the "PARK" port as
w ell as the "RUN" port, the rubber slid e valve is
defective, and the control valve can be se r v ic e d as
d escrib ed in 1970 Heavy Duty Truck S ervice
Manual ST 135-70, Section 1A, page 1-21.
NOTE: When using Valve S ervice Kit, a s s e m ­
b le new p r e -g r e a se d valve to backing plate and
p la ce valve cavity in c o r rect position to re c e iv e
control stem . Lubricate with Silicone G rease Type
G E-SS-4067 or D C -4.
IMPORTANT: B e su re to rep lace old slid e
valve (fig. 6) with new valve of the sam e th ick n ess.
WIPER MOTOR AIR LINES
(Refer to F igure 7)
A ir lin e s for m odels covered in th is supple­
ment are of nylon type lin e s with b r a ss fittin gs.
Nylon ferru le design or m etal ball s le e v e design
is available for s e r v ic e .
WIPER BLADE REPLACEMENT
(R efer to F igure 8)
1. Hold f illis te r head sc r e w with screw d riv er
and rem ove lock nut. R em ove sc rew which is
threaded into w iper arm and rem ove blade. R e­
v e r s e procedure to in sta ll.
IMPORTANT: Turning the fillis te r head block
attaching sc r e w too far into the w iper arm w ill
bend the blade arm and cau se blade to bind and
w ipe erra tic a lly .
NOTE: Curved w indshield w iper blade is de­
sign ed to accept a r e fill in ser t for s e r v ic e r e ­
placem ent.
AIR OPERATED WIPER MOTOR
SERVICING (CONV. CAB MODELS)
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 ssem b led and repaired. For repair inform ation
s e e "Troubleshooting and Repair of Wiper System "
la te r in this sectio n .
WIPER MOTOR REPLACEMENT
R em oval
1. D isconnect lin e s at m otor.
2. R em ove the four m otor mounting p la te -to -
cowl b olts and nuts.
3. Move m otor forw ard from cow l, then through
cow l opening, disconnect tra n sm issio n link from
m otor crank arm . The link attached to the right
m otor is retained with two sm a ll nut a s s e m b lie s .
The left m otor is connected to link with a spring
clip and flat w ash er. R em ove w iper motor.
Installation
NOTE: B efore in stallin g m otor, rem ove any
old sea lin g compound from around m otor mounting
su r fa c e s, then apply bead of new compound to s u r ­
fa c e s . Install m otor in the r e v e r se sequence of the
"Removal" procedure.
TRANSMISSION AND LINKAGE
REPLACEMENT
NOTE: A c c e s s to tra n sm issio n s and linkage
can be obtained from under dash panel at left sid e
and by rem oving ash tray panel at the right sid e .
The linkage connection at the m otor crank arm s is
AIR LINE LEFT RIGHT
STRAINER PARK LINE PARK LINE
Figure 5 —Dual W iper Control V a lv e Schematic
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT