Buick LeSabre 1965 Service Manual page 788

ACCESSORIES OPTIONAL HEATER-AIR CONDITIONER SYSTEM 1 1 - 5 5
Figure 11-66. If the discharge
pressure exceeds approximately
440 psi, the relief valve opens
automatically to relieve the pres-
sure and closes again when the
pressure decreases.
Opening of the relief valve will be
accompanied by a loud popping
noise, and perhaps the ejection of
some oil with the refrigerant.
Any condition that causes this
valve to open should be corrected
immediately.
m. Oil Drain Screw
An oil drain screw is located on
the under side of the compressor
shell. This screw is used just for
draining and adding oil. It is not
an oil test outlet as the oil level
cannot be checked while the com-
pressor is installed on the engine
due to the design of the compres-
sor. It is not necessary to check
compressor oil unless a large
amount of oil has been lost. This
could happen only with a sudden
breaking of a line or some other
serious break in system. If there
has been a major loss of oil, the
compressor should be removed
and drained and oil added as out-
lined under Checking Compressor
Oil and Adding Oil, paragraph
11-15, subparagraph " j " .
n. Shell
The shell of the compressor has
a mounting flange on the front end
and four threaded screws welded
to the outside at the rear. An oil
sump is formed into the bottom
of the shell with a baffle plate
over the sump on the inside of
the shell.
The compressor serial number
is located on a plate on top of
the compressor. T h i s number
should be included in all Product
Information Reports, claims or
correspondence concerning the
O-RING
DISCHARGE
TUBE
BUSHING
Figure 11-67—Service Type
Discharge Tube
compressor. The compressor
part number is also shown on the
serial number plate.
o. Magnetic Clutch and
Pulley Assembly
The pulley assembly contains an
electrically controlled magnetic
clutch, permitting the compressor
to operate only when refrigerated
air is desired.
When the compressor clutch is
not engaged, the compressor shaft
does not turn, although the pulley
is still being turned by the com-
pressor belts.
The clutch armature plate, which
is the movable member of the
clutch drive plate assembly, is
attached to the assembly by
means of flat springs. The hub
of this assembly is pressed over
the compressor shaft and is
aligned with a square drive key
located in the keyway of. the com-
pressor shaft. This clutch drive
plate assembly is held in place
with a nut. See Figures 11-68
and 11-69.
A two-row ball bearing is pressed
into the hub of the pulley assem-
bly and held in p l a c e by a
bearing-to-pulley retainer wire.
The pulley assembly and bearing
is pressed over the front head of
the compressor and held in place
by a bearing - to - head retainer
ring.
The coil and housing assembly
has 3.85 ohms resistance at 80°
F. (surrounding temperature) and
should not demand more than 3.2
amperes at 12 volts D.C.
Three protrusions on the rear of
the coil housing fit into align-
ment holes in the front head of
the compressor. When the coil
and housing assembly is aligned
and engaged with the front head,
it is secured in place by the coil
and housing retainer ring. If re-
moved, it is important that the
coil and housing be reassembled
in their original position so that
the wiring harness connector may
be plugged on the coil terminals.
When the air conditioner controls
are set for cooling, current flow-
ing through the coil creates a
magnetic f o r c e which flows
through the pulley to draw the
armature plate rearward toward
the pulley. As the armature plate
moves toward the pulley, it con-
tacts the pulley face.
The design of the clutch and coil
is such that magnetic force locks
the armature plate and pulley to-
gether as one unit. Since the
armature plate hub is pressed on,
and keyed to the compressor
shaft, the shaft will then turn with
the pulley.
When the air conditioner controls
are turned off, the electric cir-
cuit to the compressor clutch is
open and the magnetic pull on the
clutch no longer exists.
The springs of the clutch drive
plate assembly will then pull the