1993 CHEVROLET DYNASTY oil

FIXED DISPLACEMENT COMPRESSORÐMODEL SD709P INDEX
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Compressor ............................. 38
Compressor Clutch/Coil Assembly ............ 38
Compressor Shaft Seal .................... 41 Cylinder Head/Valve Plate
.................. 44
Description ............................. 38
Refrigerant System Diagnosis ............... 45
DESCRIPTION
The Sanden compressor is a 7 piston design. Sys-
tem lubrication is provided by 135 ml 615 ml (4.6 oz.
6 0.5 oz.) of 500 viscosity refrigerant oil.
The clutch used on the compressor consists of 3 ba-
sic components:
² The pulley
² Front plate
² Field coil
The pulley and field coil are attached to the front
head of the compressor with tapered snap rings. The
hub is keyed to the compressor shaft and is retained
on the shaft with a self-locking nut. Special service
tools are required to remove and install the clutch
plate on the compressor shaft.
COMPRESSOR
The A/C compressor may be removed and posi-
tioned without discharging the refrigerant system.
Discharging is not necessary if removing the A/C
compressor clutch/coil assembly, engine, cylinder
head, or generator.
WARNING: REFRIGERANT PRESSURES REMAIN
HIGH EVEN THOUGH THE ENGINE MAY BE
TURNED OFF. BEFORE REMOVING A FULLY
CHARGED COMPRESSOR, REVIEW THE SAFETY
PRECAUTIONS AND WARNINGS SECTION IN THIS
GROUP. DO NOT TWIST OR KINK THE REFRIGER-
ANT LINES WHEN REMOVING A FULLY CHARGED
COMPRESSOR. SAFETY GLASSES MUST BE
WORN.
REMOVAL
(1) Disconnect negative cable from battery.
(2) Loosen and remove drive belts (refer to group
7, Cooling System) and disconnect compressor clutch
wire lead. (3) Remove refrigerant lines from compressor (if
necessary). (4) Remove compressor attaching nuts and bolts.
(5) Remove compressor. If refrigerant lines were
not removed, lift compressor/clutch assembly and tie
it to a suitable component. To install, reverse the removal procedure.
COMPRESSOR CLUTCH/COIL ASSEMBLY
The magnetic clutch consists of a stationary elec-
tro-magnetic coil and a rotating pulley and plate as-
sembly. The electromagnetic coil is retained on the com-
pressor with a snap ring and is dimpled to maintain
its position. The pulley and plate assembly are mounted on the
compressor shaft. When the compressor is not in operation, the pul-
ley free wheels on the clutch hub bearing. When the
coil is energized the plate is magnetically engaged
with the pulley and turns the compressor shaft.
REMOVAL
(1) Insert the 2 pins of the front plate spanner into
any 2 threaded holes of the clutch front plate (Fig.
1). Hold clutch plate stationary. Remove hex nut
with 19 mm (3/4 inch) socket.
(2) Remove clutch front plate using puller. Align
puller center bolt to compressor shaft (Fig. 2). Thumb
tighten the puller bolts into the threaded holes. (3) Turn center bolt clockwise with 19 mm (3/4
inch) socket until front plate is loosened. (4) Remove shaft key by lightly tapping it loose
with a slot screwdriver and hammer (Fig. 3). (5) Remove the external front housing snap ring
by using spread type snap ring pliers (Fig. 4).
Fig. 1 Hex Nut Removal
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(6) Insert the lip of the jaws of the rotor puller into
the snap ring groove exposed in the previous step
(Fig. 5). (7) Place rotor puller shaft protector over the ex-
posed shaft. (8) Install the puller plate and bolt (Fig. 6). 2 bolts
go through the plate and into the jaws. Finger
tighten bolts. (9) Turn puller center bolt clockwise using 3/4 inch
socket until rotor pulley is free. (10) Loosen coil lead wire from clip on top of com-
pressor front housing (Fig. 7). (11) Using spread type snap ring pliers, remove
snap ring and field coil (Fig. 8).
INSTALLATION
(1) Install the field coil with the snap ring. (2) Place coil lead wire under clip on top of com-
pressor front housing and tighten the retaining
screw. (3) Support the compressor on the 4 mounting ears
at the compressor rear. If a vise is being used, clamp
only on the mounting ears. Never clamp on the com-
pressor body. (4) Align rotor assembly squarely on the front
housing hub.
Fig. 2 Clutch Front Plate Removal
Fig. 3 Shaft Key Removal
Fig. 4 External Snap Ring Removal
Fig. 5 Install Shaft Protector
Ä HEATING AND AIR CONDITIONING 24 - 39

(5) Using Rotor Installer Set, place the ring part of
the set into the bearing cavity (Fig. 9). Make certain
the outer edge rests firmly on the rotor bearing inner
race. (6) Place the tool set driver into the ring (Fig. 10).
(7) With a hammer, tap the end of the driver while
guiding the rotor to prevent binding. Tap until the
rotor bottoms against the compressor front housing
hub. Listen for a distinct change of sound during the
tapping process. (8) Install external front housing snap ring with
spread type snap ring pliers. (9) Install front plate assembly.
² Check that original clutch shims are in place on
compressor shaft.
² Replace compressor shaft key.
² Align front plate key-way to compressor shaft key.
(10) Using shaft protector, tap front plate to shaft
until it has bottomed to the clutch shims (Fig. 11).
Listen for a distinct change of sound during the tap-
ping process.
Fig. 6 Install Puller Plate
Fig. 7 Loosen Coil Lead Wire
Fig. 8 Snap Ring and Field Coil Removal
Fig. 9 Rotor Installer Set
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Shaft seal replacement should be done on the
bench. Never use any old parts of the shaft seal
assembly. Rebuild the complete assembly. (4) Using either of the snap ring tools, insert the tool
points into the 2 holes of the felt ring metal retainer.
Lift the felt ring out (Fig. 3).
(5) Remove the clutch shim. Use O-ring hook and a
small screwdriver to prevent shim from binding on
shaft (Fig. 4). (6) Remove shaft seal seat retaining snap ring with
pinch type snap ring pliers (Fig. 5). (7) Remove the shaft seal seat, using seal seat tool
(Fig. 6). (8) Insert the Seal Remover and Installer Tool
against the seal assembly. Press down against the
seal spring and twist the tool until it engages the
slots of the seal cage (Fig. 7). Lift out seal assembly.
INSTALLATION
(1) Clean seal cavity thoroughly with a lint-free or
synthetic cloth and clean refrigerant oil. Then blow
out with dry pressurized vapor. (2) Make sure all foreign substances are thor-
oughly removed. (3) Insert Seal Sleeve Protector over compressor
shaft (Fig. 8).
Fig. 4 Clutch Shim Removal
Fig. 5 Snap Ring Removal
Fig. 2 Remove Clutch Front Plate
Fig. 3 Felt Ring Removal
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(4) Do not touch the new seal lapping surfaces. Dip
the mating surfaces in clean refrigerant oil before
proceeding. (5) Engage slots of Seal Remover and Installer to
new seal cage and insert seal assembly firmly into
place in the compressor seal cavity (Fig. 9). Twist
tool in opposite direction to disengage tool from seal
cage. Remove tool. (6) Coat seal retainer with clean refrigerant oil.
Use seal seat tool to install (Fig. 10). Press lightly
against seal. (7) Install snap ring. Beveled edge lies outward
from compressor. Flat side lies toward compressor. It
may be necessary to lightly tap the snap ring to se-
curely position it in its groove. (8) Replace clutch spacer shims.
(9) Tap new felt ring into place (Fig. 11).
(10) Align front plate key-way to compressor shaft
key. (11) Using shaft protector, tap front plate to shaft
until it has bottomed to the clutch shims. Listen for
a distinct change of sound during the tapping pro-
cess. (12) Replace shaft hex nut. Tighten the hex nut to
37 N Im (27 ft. lbs.) torque.
(13) Check air gap with feeler gauge (Fig. 12). The
specification is 0.406-0.787 mm (0.016-0.031 inch). If
Fig. 6 Shaft Seal Seat Removal
Fig. 7 Seal Assembly Removal
Fig. 8 Insert Seal Sleeve Protector
Fig. 9 Compressor Shaft Seal Installation
Ä HEATING AND AIR CONDITIONING 24 - 43

(3) Visually inspect all parts for damage.
(4) Separate the valve plate from the cylinder
block (Fig. 2).
INSPECTION
Visually inspect the rear valves and discharge re-
tainer for damage. Discard any component if any por-
tion is damaged.
CLEANING
If valve plate and/or cylinder head are to be reused,
carefully remove gasket materials using the gasket
scraper. Do not damage cylinder block or valve plate
surfaces.
INSTALLATION
When installing the cylinder head valve plate,
use the new gaskets in the parts kit. (1) Coat new valve plate gasket with clean refriger-
ant oil. (2) Install valve plate gasket by aligning valve plate
gasket to locating pin holes and oil orifice in cylinder
block. (For easy reference, the gaskets have a notch at
the bottom outside edge). (3) Install valve plate by aligning valve plate locat-
ing pins to the pin holes in the block and position valve
plate. (4) Install cylinder head and tighten bolts in order to
32 N Im (24 ft. lbs.) torque (Fig. 3).
REFRIGERANT SYSTEM DIAGNOSIS
Refer to the Refrigerant System Diagnosis chart in
this section.
Fig. 2 Valve Plate Removal
Fig. 3 Cylinder Head Bolt Torque Sequence
Ä HEATING AND AIR CONDITIONING 24 - 45

COMPONENT SERVICE PROCEDURES INDEX
page page
Air Distribution Duct ...................... 50
Air Distribution Duct ...................... 52
Ambient Switch .......................... 47
Blend-Air Door .......................... 64
Blower Motor ............................ 58
Blower Motor Wheel Assembly .............. 58
Blower Resistor Block ..................... 49
Condensate Drain Tube ................... 64
Condenser Assembly ...................... 57
Condenser Fan Control Switch .............. 47
Defroster Duct ........................... 51
Defroster Duct Adapter .................... 51
Defroster Ducts/Demister Ducts and Hoses ..... 52
Differential Pressure Cut-Out Switch Diagnosis . . 48
Evaporator Coil .......................... 64 Expansion Valve
......................... 55
Filter-Drier Assembly ...................... 57
Fin-Sensing Cycling Clutch Switch ............ 53
Heater Core ............................ 64
Heater Hoses ........................... 51
Heater-A/C Unit AssemblyÐRemoval and Installation ............................ 61
Heater-A/C Unit Recondition ................ 63
Low or Differential Pressure Cut-Off Switch ..... 54
Temperature Control CableÐAA,AP,AG and AJ Models ............................ 49
Temperature Control CableÐAC/AY Models .... 48
Vacuum ActuatorÐFresh/Recirc Door ......... 50
Vacuum ActuatorsÐMode Doors ............. 52
AMBIENT SWITCH
The ambient switch is a temperature sensor located
in front of the condenser behind the grille (Fig. 1).
The ambient switch prevents the compressor from
engaging in cold temperatures. The ambient switch
is a sealed factory calibrated unit. It must be re-
placed if defective.
AMBIENT SWITCH TEST
(1) Disconnect ambient switch wire connector.
(2) Using a suitable ohm meter or continuity
tester, test for continuity across the ambient switch
terminals. (a) At temperature above 10ÉC (50ÉF), the switch
circuit should be complete. (b) Chill the switch with ice to below 10ÉC (50ÉF)
and test for continuity. The switch circuit should
be open, with continuity not detected.
Replace ambient switch if defective.
REMOVAL AND INSTALLATION
(1) Remove the one attaching screw.
(2) Remove the sensor/bracket assembly from the
vehicle. To install, reverse the preceding operation.
CONDENSER FAN CONTROL SWITCH
The Fan Control Switch is located on the plumbing
discharge line at the A/C compressor (Fig. 2). The fan
control switch cycles the radiator/condenser fan on and
off by monitoring the compressor discharge pressure.
The radiator top tank temperature sensor can over ride
the function of the fan control switch. It can cycle the
radiator/condenser fan on and off depending on the
engine temperature.
FAN CONTROL SWITCH DIAGNOSIS
Review Safety Precautions and Warnings before pro-
ceeding. Connect a manifold gauge set to the refriger-
ant system service ports. Work area temperature can
not be below 21ÉC (70ÉF).
Fig. 1 Ambient Temperature Sensor SwitchÐTypical Mounting
Fig. 2 Condenser Fan Control Switch
Ä HEATING AND AIR CONDITIONING 24 - 47

WARNING: AVOID RADIATOR/CONDENSER FAN
BLADES WHEN WORKING IN THE RADIATOR
AREA. FAN IS CONTROLLED BY TEMPERATURE
AND CAN START ANY TIME IGNITION IS ON. PER-
SONAL INJURY CAN RESULT.
(1) Disconnect fan control switch wire connector.
(2) Using a suitable jumper wire, jump across ter-
minals in wire connector. (3) Connect a suitable continuity tester across fan
control switch terminals. (4) Start engine and set idle at 1300 rpm. The ra-
diator fan should run constantly. (5) Set the A/C controls to A/C and high blower.
(6) If the high pressure gauge reads below 1102
kPa (160 psi) there should be no continuity across
the switch terminals.
CAUTION: Do not allow engine to overheat when ra-
diator air flow is blocked.
(7) Block radiator air flow with a suitable cover to
increase the high side pressure to at least 1585 kPa
(230 psi). Electrical continuity should be detected
across the fan control switch terminals. (8) Remove cover from front of vehicle to allow
high side pressure to decrease. When pressure drops
below 1102 kPa (160 psi), continuity should cease. If fan control switch is defective, replace it.
REMOVAL AND INSTALLATION
CAUTION: Refrigerant removal is not necessary
when removing the Condenser Fan Control Switch.
However, a small amount of refrigerant will vent
from the switch port. Review the refrigerant han-
dling section of Safety Precautions and Warnings in
the General Information section of this Group.
(1) Disconnect wire connector from condenser fan
control switch. (2) Loosen and quickly rotate the switch counter-
clockwise and separate from the high pressure line
switch port. To install, reverse the preceding operation.
DIFFERENTIAL PRESSURE CUT-OUT SWITCH
DIAGNOSIS
The Differential Pressure Cut-Out (DPCO) Switch
(Fig. 3) monitors the liquid refrigerant pressure on
the liquid side of the system. The DPCO is located on
the expansion valve. The expansion valve is black in
color when a variable displacement compressor is
used. The DPCO turns off voltage to the compressor
clutch coil when liquid refrigerant pressure drops to
levels that could damage the compressor. The DPCO
is a sealed factory calibrated unit. It must be re-
placed if defective.
DPCO SWITCH DIAGNOSIS
The work area must not be below 10ÉC (50ÉF) to
test the compressor clutch circuit. (1) With gear selector in park or neutral, and park
brake set, start engine and allow to idle. (2) Raise hood and disconnect DPCO switch con-
nector boot. (3) Using a suitable jumper wire, jump across the
terminals inside wire connector boot. (4) If clutch does not engage, the wiring, fuse, re-
lay, ambient switch, or high pressure cut-off switch
can be defective. Refer to Group 8W, Wiring Dia-
grams. (5) If clutch engages, connect a suitable manifold
gauge set. Read low pressure gauge. At pressure 283
kPa (41 psi) and above, DPCO switch will complete
the clutch circuit. If the low pressure gauge reads be-
low 317 kPa (46 psi), the system is low on refrigerant
charge or empty due to a leak. Refer to Testing For
Refrigerant Leaks in the Refrigerant Service Proce-
dures section. (6) Install connector boot on switch and repeat step
number 3. If the clutch does not engage, replace the
DPCO switch.
TEMPERATURE CONTROL CABLEÐAC/AY MODELS
REMOVAL AND INSTALLATION
A Temperature Control Cable is used on non-ATC
heat or heater-A/C systems only. ATC (Automatic
Temperature Control) systems use an electrically op-
erated temperature control. Refer to the ATC section
of this Group. (1) Remove the A/C-Heater control panel assembly.
Refer to A/C-Heater Control Replacement in Group
8E Instrument Panel. Disconnect the cable attaching
flag from the A/C-heater control and remove the ca-
ble from control panel.
Fig. 3 Differential Pressure Cut-Out Switch
24 - 48 HEATING AND AIR CONDITIONING Ä