Chevrolet 10 Series 1970, Service Manual

Page: 55 / 671

HEATER AND AIR CONDITIONING 1A-25
c. If a new s e rv ic e com p resso r is being installed,
drain a ll o il fro m it and rep la ce only the amount
sp ecified in Steps 3a and 3b above.
d. If a fie ld rep aired com p resso r is being installed,
add an additional 1 fluid oz. to the com p ressor.
4. In the event that it is not p ossib le to idle the com ­
p r e s s o r as outlined in Step 1 to e ffe c t o il return to
it, p ro ceed as fo llo w s:
a. R em ove the co m p ressor, drain, m easure and
d isca rd the o il.
b. If the amount drained is m ore than 1-1/2 fluid
oz. and the system shows no signs o f a m ajor
leak, add the same amount to the replacem ent
com p resso r.
c. I f the amount drained is le s s than 1-1/2 oz. and
the system appears to have lo st an e x c essive
amount o f o il, add 6 flu id oz. o f clean r e fr ig e r a ­
tion o il to replacem ent com p ressor, 7 fluid oz. to
a re p a ire d co m p ressor.
I f the o il contains chips o r other fo reig n m a­
te r ia l, rep lace the re c e iv e r-d e h y d ra to r and flush
o r rep lace a ll component parts as n ecessary. Add
the fu ll 11 fluid oz. o f new r e frig e ra tio n o il to the
replacem ent com p ressor.
5. Add additional o il in the follow in g amounts fo r any
system components being replaced.
E v a p o r a t o r .............................................. 3 fluid oz.
C o n d e n s e r................................................ 1 fluid oz.
R e c e iv e r-D e h y d ra to r.............................. 1 fluid oz.
NOTE: When adding o il to the co m p ressor, it
w ill be n ecessa ry to tilt the re a r end o f the
com p resso r up so that the o il w ill not run out
o f the suction and discharge ports.
Do not set
the co m p ressor on the shaft end.
COMPONENT REPLACEMENT AND MINOR REPAIR
ALL SYSTEMS
PREPARING SYSTEM FOR
REPLACEMENT OF C O M P O N E N T PARTS
A ir conditioning, like many other things, is fa ir ly sim ple
to s e rv ic e once it is understood. H ow ever, there are
certain p rocedu res, p ra c tic e s and precautions that should
be follow ed to prevent costly re p a irs , personal injury
o r damage to equipment. F o r this reason it is strongly
recom m ended that the p recedin g inform ation in this s e c ­
tion be studied thoroughly b efo re attempting to s e rv ic e
the system .
G reat em phasis must be placed upon keeping the s y s ­
tem clean. Use plugs o r caps to close system com ­
ponents and hoses when they a re opened to the atm os­
phere. Keep your w ork a rea clean.
In rem ovin g and rep lacin g any part which req u ires
unsealing the re frig e ra n t c ircu it the follow in g operations,
which a re d escrib ed in this section, must be p erfo rm ed
in the sequence shown.
1. P u rge the system by re lea sin g the re frig e ra n t to the
atm osphere.
2. Rem ove and rep lace the d efective part.
3. Evacuate and charge the system .
CA U TIO N : A lw ays w ea r p ro tective goggles
when working on re fr ig e r a tio n system s. G oggles
J-5453 are included in the set o f a ir conditioning
sp ecial to o ls.
A ls o , bew are o f the danger o f
carbon monoxide fum es by avoiding running the
engine
in closed o r im p ro p e rly ventilated
g a ra ges.
FOREIGN MATERIAL IN THE SYSTEM
W henever fo re ig n m a teria l is found in the system , it
must be rem oved b efo re re sto rin g the system to o p era ­
tion.
In the case o f com p resso r m echanical fa ilu re, p e r ­
fo r m the follow in g operations:
1. R em ove the com p ressor.
2. Rem ove the re c e iv e r-d e h y d ra to r and discard the unit.
3. Flush the condenser to rem ove fo re ig n m a teria l
which has been pumped into it.
4. Disconnect the line fro m the re c e iv e r-d e h y d ra to r
at the inlet connection o f the expansion valve. Inspect
the inlet screen fo r the presen ce o f m etal chips o r
other fo re ig n m a teria l.
If the screen is plugged,
rep lace it. Reconnect the line to the expansion
valve.
5. Install a new re c e iv e r-d e h y d ra to r.
6. Install the replacem ent com p ressor.
7. Add the n ecessa ry quantity of o il to the system (one
fluid ounce because o f re c e iv e r-d e h y d ra to r r e p la c e ­
ment plus the quantity needed fo r the replacem ent
co m p ressor - see "Checking C om p ressor O il
C h arge" under "C hecking O il."
8. Evacuate and charge the system .
9. Check system perform an ce.
REFRIGERANT LINE CO N N EC TIO N S
“ O ” Rings
A lw ays rep lace the " O " rin g when a connection has
been broken. When replacin g the "O " ring, fir s t dip it
in clean re frig e ra tio n o il. Alw ays use a backing wrench
on "O " ring fittin gs to preven t the pipe fro m tw isting and
damaging the "O " ring.
Do not overtighten. C o rre c t
torque sp ecification s a re as fo llo w s :
M etal
Tube
O.D.
Th read and
Fitting
Size
Steel
Tubing
Torqu e*
Alum .
Tubing
To rq u e*
1/4 7/16 13 6
3/8 5/8 33 12
1/2 3/4 33 12
5/8 7/8
33 20
3/4 1-1/16 33 25
*F oot Pounds.
NOTE: W here steel to aluminum connections
are being made, use torque fo r aluminum tubing.
Hose Clamps
When hose clam p connections a re encounted, sp ecial
CHEVROLET TRUCK SERVICE MANUAL