Chevrolet 1977 light duty truck, Service Manual

Page: 95 / 861

W h e n m ak in g evaporator core connections, use
new " O " rings coated with clean refrigeration oil.
9. Evacuate, charge and check system operation.
E V A P O R A T O R CORE
R eplacem ent (Fig. IB -5 5 )
1. Purge the system o f refrigerant.
2. Follow Steps l -8 o f " A / C Air D istributor Duct-
R eplacem ent".
3. Disconnect evaporator inlet and outlet connec­
tions. C a p or plug open connections at once.
4. Remove the blower-evaporator support bracket
to d oor pillar and forward engine housing screws and
lower the blow er-evaporator assembly. Disconnect the
electrical connections, pull d ra in hose through the dash
panel an d rem ove the blow er-evaporator as an assembly.
5. Remove the expansion valve sensing bulb
clam ps and disconnect the line from the evap o rato r core.
Disconnect the expansion valve inlet and outlet lines and
rem ove the expansion valve. C a p or plug all open
connections at once.
6. Remove the evap o rato r core line clamp screws.
Remove the core to case attaching screws and remove the
ev a p o ra to r core assembly.
7. To install a new core, reverse Steps 1-6 above.
T ra n s fe r the core screen to the new core. NOTE: Add
three ounces o f new re frigeration oil to a new core. Use
new " O " rings, coated with clean refrigeration oil, when
connecting all re frig eran t lines. T ran sfer thermister to
the new evaporator.
N O T E : Make sure the expansion valve sensing
bulb makes good contact with the core connector
block.
8. Evacuate, charge and check system operation.
A IR IN LE T VALVE ■ G M O DEL
Replacem ent (Fig. IB -5 6 )
Follow Steps 1-10 o f "Fleater Air D istrib u to r and
Extension Duct Extension Duct R e p la c e m e n t" procedure.
11. Remove duct assembly. Disconnect vacuum
hose.
12. Remove vacuum valve.
13. To reassemble. Reverse Steps 1-12.
T E M P E R A T U R E DOOR CABLE - G M ODEL
Replacement
Follow Steps 1-10 o f " H e a te r Air D istributor and
Extension Duct R eplacem ent" procedure.
11. Disconnect tem perature door control cable at
heater case.
12. Disconnect tem perature door control cable at
control.
13. Make up new cable.
14. To reassemble. Reverse Steps 1-13.
C O N TR O L
Replacement (Fig. IB -5 7 )
1. Disconnect the battery ground cable.
2. Remove the h ea d la m p switch control knob.
3. Remove the instrum ent panel bezel.
4. Rem ove the control to in s tru m e n t panel
attaching screws.
5. Remove the tem perature cable eyelet clip and
m ounting tab screw.
6. Pull the control through the instrum ent panel
opening as follows: First pull the lower right mountin
tab through the opening, then the upper tab and finally
the lower right tab.
7. Disconnect electrical and vacuum connections
and remove the control assembly.
Fig. 1B-56 - Air Inlet Valve (G Model C60 System)
Fig. IB -5 7 -C o n tro l (G Model C60 System)