Chevrolet 70 Series 1970, Service Manual

Page: 158 / 841

CAB AND BODY MOUNTINGS 1-127
9. U sing leak d etector (J-6084) (fig. 24), check
com p lete sy ste m for lea k s as explained la ter under
"Checking For L eaks."
SERVICE STATION METHOD
The (J-8393) D eluxe P ortable A ir Conditioner
S e r v ic e Station su p p lies a ll evacuating and ch arg­
ing equipment a sse m b le d into a com pact portable
unit.
1. Be certain c o m p resso r hand sh u t-off v alves
a re c lo sed to gauge fittin g s (counterclockw ise).
2. B e certain a ll v a lv e s on charging station
a re c lo sed .
3. Connect high p r e s s u r e gauge lin e (with J -
9459 attached) to c o m p r e sso r high p r e s s u r e gauge
fitting or to co r e rem over Tool (J-22132-01) (if
used).
4. Turn high p r e s s u r e hand sh u t-o ff valve one
turn clo ck w ise, and high p r e ssu r e control (
2
) one
turn cou n terclock w ise (open). Crack open low p r e s ­
su re control (
1
) and allow refrig era n t gas to h iss
from low p r e s s u r e gauge lin e for th ree seco n d s,
then connect low p r e s s u r e gauge line to low p r e s ­
su re gauge fittin g on co m p r e sso r . P la c e (J-5420)
adapter on h o se, then attach adapter to gauge fitting
or fitting c o r e rem o v er tool.
F illin g Charging C ylinder
1. Open control valve on refrig era n t container.
2. Open valve on bottom of charging cylinder
allow ing refrigeran t to en ter cylinder.
3. B leed charging cylin d er to valve (behind
control panel) only as required to allow r e fr ig e r ­
ant to en ter cylin d er. When refrig era n t re a ch es
d e sir e d charge le v e l (3% or 4^ lb s.), c lo s e valve at
bottom of charging cylin d er and be certain cylinder
b leed valve is c lo se d se c u r e ly .
NOTE: W hile fillin g the cylinder, it w ill be
n e c e s s a r y to c lo s e the bleed valve p erio d ica lly to
allow boiling to su b sid e so that refrigeran t le v e l
in the charging cy lin d er can be accu rately read.
Charging The S ystem
U sing S er v ice Station J-8393
1. With charging station in sta lled a s p r e v i­
ou sly d escrib ed , rem ove low p r e ssu r e gauge lin e
at c o m p r e sso r .
2. Crack open high (No. 2) and low (No. 1)
p r e s s u r e control v a lv es on station, and allow r e ­
frigeran t gas to purge from sy ste m . Purge slow ly
enough so that o il does not esca p e from sy ste m
along with refrigeran t.
3. When refrigeran t flow nearly sto p s, connect
low p r e s s u r e gauge lin e to co m p r e sso r .
4. Turn on vacuum pump and open vacuum con­
tr o l valve (No. 3).
5. With s y s te m purged a s d irecte d p rev io u sly ,
run pump until 26-28 inches of vacuum is obtained.
Continue to run pump for 15 m inutes after the s y s ­
te m rea ch es 26-28 in ch es vacuum.
NOTE: in a ll evacuating p roced u res, the s p e c i­
fication of 26-28 inches of m ercury vacuum is used .
T h ese fig u res a re only attainable at o r near sea
le v e l. For each 1,000 fee t above se a le v e l w here
th is operation is being perform ed , the sp e c ific a ­
tion s should be lo w ered by one inch.
For Example: 5,000 ft. elevation only 21 to 23
in ch es vacuum can norm ally be obtained.
6
. If 26-28 in ch es vacuum (co rrected to se a
lev el) cannot be obtained, c lo s e vacuum control
valve (No. 3) and shut off vacuum pump. Open r e ­
frigeran t control valve (No. 4) and allow som e r e ­
frigeran t to enter sy ste m . L ocate and rep air a ll
le a k s.
7. A fter evacuating fo r 15 m inutes, add V2-Vo.
o f refrigeran t to sy ste m a s d escrib ed in Step
6
p r e v io u sly . P urge th is ^ -lb . and r e -ev a cu a te for
15 to 30 m inutes. T his second evacuation is to be
certain that a s much contam ination is rem oved
from the sy ste m as p o ssib le .
8
. Only a fter evacuating as d irected p rev io u sly
sy ste m is ready for charging. Note reading on
sigh t g la s s of charging cylinder. If it does not con­
tain a su fficien t amount for a full charge, f ill to
the proper le v e l.
9. C lo se low p r e s s u r e valve on charging s ta ­
tion. Fully open station refrig era n t control valve
(No. 4) and allow a ll liquid refrigeran t to enter
sy ste m . When full charge of refrigeran t has en ter­
ed sy ste m , turn o ff refrig era n t control valve (No.
4) and c lo s e both hand sh u t-off v a lv e s.
10. If fu ll charge of refrigeran t w ill not enter
sy s te m , c lo s e high p r e s s u r e control and r e fr ig e r ­
ant control v a lv e s. Start engine and run at slow
id le w ith co m p resso r operating. Crack refrigeran t
control valve (No. 4) and low p r e s s u r e control on
station. Watch low sid e gauge and keep gauge below
50 p s i by regulating refrig era n t control valve.
C losin g valve w ill low er p r e s s u r e . This is to p r e ­
vent liquid refrigeran t from reaching the com ­
p r e s s o r w hile the c o m p resso r is operating. When
required charge has entered sy ste m , c lo s e r e fr ig ­
erant control valve and c lo s e low p r e ssu r e control.
11. S ystem is now charged and should be p e r ­
form ance te ste d b efore rem oving gauges.
ADDING REFRIGERANT
(SMALL AMOUNT)
The follow ing procedure should be used in add­
ing s m a ll am ounts of refrig era n t that may have
been lo s t by lea k s, or w hile opening sy ste m for
se r v ic in g the co m p r e sso r . B e fo re adding r e fr ig e r ­
ant to rep la ce that lo s t by le a k s, check co m p resso r
o il le v e l and add o il if n e c e ssa r y . See "Adding O il”
la te r .
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL