Cadillac 60 Series 1963 Shop Manual page 435

13-54
HEATING AND AIR CONDITIONING
13. Run jam nut all the way up on threaded end
of vacuum head.
14. Hold valve in a vertical position and insert
spring and O-ring end of vacuum head into
threaded end of valve cover. Apply a downward
force on vacuum head to compress spring and en-
gage threads. Tighten vacuum head approximately
ten full turns.
15. Install suction throttling valve on car as de-
scribed in Note 44b or 45b.
16. Adjust suction throttling valve as described
in Note 47.
47. Suction Throttling Valve
Adjustment
The suction throttling valve must control evap-
orator pressure to a minimum of 30 psi, (27 psi,
rear evaporator unit 75 series cars) in order to
prevent freezing of the cooling coil. To adjust
valve, proceed as follows:
a. Front Suction Throttling Valve
Use Charging Station, J- 8393, for this operation.
1. Open valve 1 on Charging Station one turn
and momentarily open and close low pressure
gage valve to purge air from line. Then close
valve 1.
2. Install Gage Adapter, J-5420 on Charging
Station low pressure line.
3. Connect Charging Station low pressure gage
line to fitting on suction throttling valve.
NOTE: Disconnect vacuum hose from dia-
phragm on front of suction throttling valve, on
75 series only.
4. Start engine and operate at 2000 rpm with
Air Conditioner operating at maximum and fan
switch on low. On 60 and 62 series cars check to
assure that vacuum is being applied to the sec-
tion throttling valve diaphragm.
5. Operate system for five minutes and check
low pressure gage reading. Low pressure should
30 psi. If adjustment is necessary, perform steps
6 and 7. If adjustment is not needed, proceed to
step 8.
6. Loosen jam nut on suction throttling valve,
turn diaphragm clockwise to increase pressure or
counterclockwise to decrease pressure until 30
psi is obtained, Fig. 13-76.
NOTE: Three complete turns of the dia-
phragm will change pressure approximately
1 psi. Turn diaphragm one turn at a time al-
Fig. 13-76 Adjusting Suction Throttling Valve
lowing time for gage to settle. Repeat if neces-
sary. Gage will not indicate actual setting
immediately. It may be necessary to tap gage
to get reading.
7. Tighten jam nut until it is snug, using care
not to overtighten.
NOTE: Install vacuum hose on suction throt-
tling valve on 75 series cars.
8. Shut off engine and disconnect Charging Sta-
tion line. Replace cap on pressure fitting on suc-
tion throttling valve.
b. Rear Suction Throttling Valve
(75 Series Only)
1. Remove trim cover from shelf in luggage
compartment.
2. Remove plate from rear of evaporator to
gain access to suction throttling valve.
3. Perform steps 1 through 5, Section a.
4. Operate system for five minutes and check
low pressure gage reading. Low pressure should
be 27 psi. If adjustment is necessary, perform
steps 6 and 7, Section a. If adjustment i s not
needed, proceed to step 8.
5. Install access plate on rear evaporator and
r e p l a c e trim cover on s h e l f in luggage
compartment.