GMC 1982 Light Duty Truck, Service Manual

Page: 69 / 1435

IB -26 AIR CONDITIONING
O N VEHICLE SERVICE
EV A C U A TIN G A N D C H A R G IN G PROCEDURES
M ETA L TUBE
O UTSIDE
D IA M E T E R
T H R E A D AND
F IT T IN G SIZE
STEEL
T U B IN G
TO RQ UE
L B . F T . N m
a l
D
m i n
O W S
r
COPPER
TU BING
TORQUE
LB. FT. N m
N O M IN A L
TORQUE
W RENCH SPAN
1/4
7/16 10-15 14-20 6-7 7-9 5/8
3/8 5/8 30-35 41-48 11-13 15-16 3 /4
1/2 3/4
30-35 41-48 16-20 20-27 7/8
5/8
[ I -
30-36 4 1 4 8 21-27
29-37
1 1 /ie
....... 3/4
1 1/18 30-36 41-48
28-33 38-46
P R E C A U TIO N A R Y SERVICE MEASURES
Before any service is attem p te d which requires opening
of refrig eran t lines or com ponents, the person doing the
work should be thoroughly fam iliar with the inform ation
under P R E C A U T IO N S IN H A N D L IN G R e frig e ra n t-12,
P R E C A U T IO N S IN H A N D L IN G R E F R IG E R A N T
L IN E S A N D F IT T IN G S M A IN T A IN IN G C H E M IC A L
S T A B IL IT Y IN T H E R E F R IG E R A T IO N S Y S T E M ,
A N D R E F R IG E R A N T C H A R G IN G P R E C A U T IO N S
and should follow very c a re fu lly th e D IS C H A R G IN G ,
E V A C U A T IN G , O IL A D D IT IO N A N D C H A R G IN G
T H E R E F R IG E R A N T S Y S T E M instructions given on the
following pages for the unit being serviced.
Sealing caps should be removed from subassem blies
ju st prior to m aking connections for final assem bly. Use a
sm all am ount of clean 525 viscosity refrigerant oil on all
tube and hose joints. Always use new " O " rings dipped in
the clean 525 viscosity re frig eran t oil when assem bling
joints. T he oil will aid in assem bly and help provide a leak-
proof joint. W hen tightening joints, use a second wrench to
hold stationary part of connection so th a t a solid feel can be
attain ed . This will indicate proper assembly.
T ighten all tubing connections, as shown in torque
C h a rt 1B-8. Insufficient or excessive torque when tightening
can result in loose joints or deform ed joint parts. E ither
condition can result in refrig eran t leakage.
D IS C H A R G IN G E V A C U A T IN G A D D IN G OIL A N D
C H A R G IN G PROCEDURES FOR CCOT A / C
SYSTEMS
T he refrig eran t system m ay be D ischarged, Evacuated
and C h a rg e d using J -2 3 500-01 a ir cond itio n in g service
C harging S tatio n or the J-5725-04 M anifold and G age Set,
and 420 m l-14 oz. disposable cans of R efrig e ra n t-12.
C harging lines from the C harging S tation or M anifold
and G age Set require the use of gage adapters to connect to
the system service fittings. A stra ig h t gage A dapter J-5420
and a 90° angle gage A d ap ter J-9459 are available (See
A /C Special Tools).
Always w ear goggles and w rap a clean cloth around
fittings and connections w hen doing w ork th a t involves
opening the refrigeration system. If liquid refrig eran t comes
into contact with the skin or eyes injury can result.
• Before rem oving and replacing any of the air
conditioning refrig e ratio n lines or com ponents, the
system m ust be com pletely discharged of R egrigerant-
1 2
.
• Always use service valve and pressure gage sets during
evacuation and charging procedures.
• Do not charge while com pressor system is hot.
• Always discharge system at low-side service fitting and
perform the entire evacuate and charging procedure
through the low-side service fitting.
• Do not connect high pressure line or any line to the
high-side service fitting d u rin g d isch arg in g and
charging procedures.
C A U TIO N : N ever rem ove a g a g e line from its
a d a p te r w h e n line is connected to A /C system.
A lw a y s rem ove th e line a d a p te r from the service
fittin g to disconnect a lin e . Do not rem o ve
ch a rg in g hose a t g a g e set w h ile a tta c h e d to
service low -side fittin g . This w ill result in com plete
discharge of system d u e to th e depressed schrader
valve in service low -side fittin g a n d m a y cuase
personal injury d u e to escaping R e frig e ra n t-1 2.
D IS C H A R G IN G THE CCOT A / C SYSTEM
In replacing any of the air conditioning refrigeration
com ponents the system m ust be com pletely discharged of
R e frig e ra n t-12.
Always discharge system at low side service fitting.
1. W ith ignition turned O F F , remove protective cap from
L O W -S ID E service fitting and connect C h arg in g
Station J-2 3 500-01 G age Set as indicated in Figure
1 B-12.
If ch arg in g statio n J -2 3 500-01 is not being used,
discharge system by slowly connecting a gage hose to
low-side service fitting on A c c u m u la to r and
discharging into oil bottle (Fig. I B - 12). As hose is
S L O W L Y tig h ten ed down onto sc h ra d e r valve,
R efrig e ra n t-12 will be in to discharge from the system
into the container. If no discharge occurs, check for
missing or defective schrader depressor in hose fitting.
2. W ith the low-side of system fully discharged, check
high-side system fitting (on liquid line or muffler) for
rem aining pressure.
3. If pressure is found, attem p t to discharge high-side
using sam e p rocedure as used for low-side. (T his
condition indicates a restriction on the high-side and
the cause m ust be diagnosed and co rre cted before
evacuating and charging the system ).
4. W hen the system is com pletely discharged (no vapor
escaping with hose fully-tightened down), m easure,
record am ount and discard the collected refrigerant oil.
If this q u antity is 15 ml (1 /2 oz.) or more, this am ount
of new 525 viscosity refrigerant oil m ust be added to
system , plus any q u a n tity in rem oved p a rts before
evacuation and charging with R e frig e ra n t-12 (R efer to
C C O T R efrigerant Oil D istribution for specific q u an ­
tity of oil norm ally retained in rem oved parts).