1993 DODGE TRUCK Service Repair Manual

24
- 20
HEATING
AND AIR
CONDITIONING

• (3) Turn
3
refrigerant manifold valves completely
clockwise
to
puncture
the
cans
and
close
the
mani­
fold valves.
(4) Purge
the air
from
the
charging line
by
loosen­
ing
the
charging hose
at the
manifold gauge
set and

turn
one of the
refrigerant valves counterclockwise. When
the
refrigerant
gas
starts escaping from
the

loose connection, tighten
the
hose.
(5) Fully open
all 3
refrigerant manifold valves
and place
the
cans
of
refrigerant into
a pan
contain­
ing 52°C (125°F) water.
The
water will warm
the

charging
can and aid in the
transfer
of the
charge
into
the
system.
(6) Start
the
engine
and
move
the
controls
to A/C

low blower position.
The electronic temperature cycling switch will pre­
vent
the
clutch from engaging until refrigerant
is
added
to the
system.
If the
clutch does engage,
re­

place
the
switch before proceeding
any
further. (7) Charge through
the
suction side
of the
system
by slowly opening
the
suction manifold valve. Adjust
the valve
as
necessary
so
charging pressure does
not
exceed
345
kPag
(50
psig). Maintain
the
temperature
of
the
water
in the pan by
adding warm water
as

necessary. (8) Adjust
the
engine speed
to a
fast idle
of
approx­
imately
1,300 RPM.
(9) When
all 3
cans
of
refrigerant
are
completely
empty, close
the
manifold gauge
set
valves
and re­

frigerant manifold valves. The maximum refrigerant charge
is 44 oz.

REFRIGERANT
LEAK REPAIR PROCEDURE

LOST CHARGE If
the
system
has
lost
all
charge
due to a
leak: (1) Evacuate
the
system.
(2) Charge
the
system with approximately
1
pound
of refrigerant. (3) Locate
all
leaks.
(4) Repair
all
leaks.
(5) Replace filter-drier bottle.

CAUTION:
Replacement
filter-drier
units
must
be

sealed
while
in
storage.
The
drier
used
in
these

units
absorbs
and
traps
moisture
quickly
upon
ex­

posure
to the
atmosphere.
When
installing
a
drier,

have
all
tools
and
supplies ready
for
quick
reas­

sembly
to
avoid keeping
the
system open
any
longer
than
necessary.

(6) Check system
oil
level. (7) Evacuate
and
charge
the
system.
LOW CHARGE If
the
system
has not
lost
all of its
refrigerant
charge; locate
and
repair
all
leaks.
If it is
necessary
to increase
the
system pressure
to
find
the
leak
(be­
cause
of an
especially
low
charge),
add 230 g (1/2 lb)

of refrigerant.
If
there
has
been
a
significant
oil
loss,
check
the
system
oil
level.
If
leak repair
was
possible
without discharging system
and an oil
level check
was
not
necessary,
use
procedure
for
correcting
low

refrigerant level.

CORRECTING
LOW
REFRIGERANT LEVEL
Since
the
refrigeration system
is
completely sealed,
the refrigerant level will
not be low
unless there
is a
leak
in the
system. Before adding refrigerant where
the
cause
of a low

level
is not
known,
the
system should
be
tested
for

leaks.
Assuming that leaks have been corrected without
discharging
the
system, proceed with partial charge.
Install
and
connect manifold gauge
set.
(1) Close both manifold gauge
set
valves. Open
manifold gauge
set
needle valve.
(2) Connect
the
suction gauge test hose
to the
suc­
tion service port
of the
compressor. Connect
the
dis­ charge gauge test hose
to the
discharge service port. (3) Connect
an end of
long test hose
to the
center
manifold outlet,
and
other
end to
refrigerant dispens­ ing manifold. (4) Close
the 2
dispensing manifold valves
and

open remaining dispensing manifold valve. Remove
protective
cap
from opened valve.

WARNING: NEVER
USE
THESE CANS
TO
CHARGE
INTO
THE
HIGH
PRESSURE SIDE
OF
THE
SYSTEM

(COMPRESSOR
DISCHARGE
PORT)
OR
INTO
A
SYSTEM
THAT
IS AT
HIGH
TEMPERATURE.
THE
HIGH
SYSTEM PRESSURES COULD
BE
TRANS­
FERRED
INTO
THE
CHARGING
CAN
CAUSING
IT

TO EXPLODE.

(5) Screw
a can of R-12 to the
opened manifold
valve.
Be
sure gasket
is in
place
and in
good condi­
tion. Tighten refrigerant
can and
manifold locking nut
to
ensure
a
good seal.
Do not
overtighten.
Tighten
to 9.5 N*m (7 ft. lbs.)
torque,
if
gasket
is in
good condition.
(6) Turn manifold valve (above
the
refrigerant
can)

completely clockwise
to
puncture
the can.
This closes
the valve
and
seals
the
refrigerant
in the can.

CAUTION:
Do not
heat refrigerant
12
above
52°C

(125°F).

(7) Place refrigerant
can in a
large
pan of
water
heated
to
52°C (125°F). Place
pan of
water containing
the refrigerant
can on an
accurate scale
so the
amount
of
refrigerant added
can be
weighed. Open
the refrigerant manifold valve.
(8) Purge
all air
from test hoses.
Air in the
system
will
be
trapped
in the
condenser causing abnormally
high discharge pressures
and
interfering with con­ densing
of the
refrigerant.

•

HEATING
AND AIR
CONDITIONING
24 - 21 (a) Loosen both test hoses at the manifold gauge
set. Tighten the hoses as soon as the air is purged. (b) Loosen charging hose connection at manifold
gauge set. This will purge air from the charging

hose.
Tighten connection as soon as air is purged.
(9) With vehicle windows open and hood up, oper­
ate engine at 1,300 RPM. (10) Place air conditioner control on A/C and place
the fan switch on high. (11) If necessary, block the condenser to maintain
a discharge pressure of 1 550-1 725 kPag (225-250

psig).
System must be charged through the evapora­
tor suction service ports as follows:
(a) Slowly open the suction service gauge valve.
Meter flow of refrigerant by adjusting the suction service gauge valve so the pressure registered at
the suction service gauge does not exceed 345 kPag

COMPRESSOR
J
(50
psig). Keep refrigerant container upright.
(b) Add refrigerant gas until there is no foam visi­
ble at the sight glass. As soon as all foam clears, note the weight registered on the refrigerant scale.
(c) Watch the refrigerant weighing scale and add
437 g (14 oz.) of refrigerant (equivalent to 1 can).
(d) Close the suction gauge valve.

CAUTION:
TOO
much
refrigerant
in the
system
can

cause
abnormally high discharge pressures. Care
must
be
used
so the
exact recommended amount
of
refrigerant
is
added
after
foam clears
in the
sight

glass.

(e) Close dispensing manifold valve. Remove test
hoses and adapters from the service ports of com­
pressor and install protective caps at service ports.

RVICE (SD-709)

INDEX

page

Compressor
21

Compressor
Shaft Seal
.................... 25
The A/C system uses a 7 piston design Sanden SD-
709 compressor. Designated the SD-709, the compres­
sor is mounted on the front right side of the engine
and is driven by a serpentine belt.
System lubrication is provided by 135cc ±15cc (4.6
cu. in. ±0.5 cu. in.) of 500 viscosity refrigerant oil.
The clutch used on the compressor consists of 3 ba­
sic components:
(1) The pulley.
(2) The front plate. (3) The field coil.
The pulley and field coil are attached to the front
head of the compressor with 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
REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Disconnect the clutch lead wire.
(3) Remove the discharge and inlet (suction) ser­
vice valves from the compressor. Plug or tape all the
openings.
(4) Refer to Group 7, Cooling System and remove
the drive belt(s). (5) Remove the bolts and lift the compressor from
the mounting bracket (Fig. 1).
page

Cylinder Head
/
Valve Plate
27
Magnetic
Clutch
22

Fig.
1
Compressor
Mounting

INSTALLATION
If a replacement compressor is being installed,
check the oil level. Add or subtract oil as necessary.
Install the magnetic clutch on the compressor.
(1) Install the compressor on the mounting bracket.
Tighten the bolts to 27 N*m (20 ft. lbs.) torque.
(2) Refer to Group 7, Cooling System and install
the drive belt(s).
(3) Check the belt tension.
@ New drive belt-800-900 N (180-200 lbs-f).
• Used belt-623-712 N (140-160 lbs-f).

24 - 22
HEATING
AND AIR
CONDITIONING

•
(4)
Remove the tape or plastic plugs from all the
suction and discharge openings and install the ser­
vice valves on the compressor.

(5)
Connect the clutch lead wire.
(6) Connect the negative cable to the battery.

(7)
Evacuate, charge and test the system for leaks.

MAGNETIC
CLUTCH
The magnetic clutch consists of a stationary electro­
magnetic coil and a rotating pulley and plate assembly. 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.
J8924-18

Fig.
3
Clutch
Front
Plate
REMOVAL

(1) Insert the 2 pins of the front plate spanner into
any 2 threaded holes of the clutch front plate (Fig.

2).
Hold clutch plate stationary. Remove hex nut. (2) Remove clutch front plate using puller. Align
puller center bolt to compressor shaft (Fig. 3). Thumb tighten the puller bolts into the threaded holes. (3) Turn center bolt clockwise until front plate is
loosened. (4) Remove shaft key by lightly tapping it loose
with a slot screw driver and hammer (Fig. 4).
(5)
Remove the external front housing snap ring
(Fig. 5).
J8924-19

Fig.
4 Shaft Key

J8924-20

Fig.
5 External
Snap Ring

HEATING
AND AIR
CONDITIONING
24 - 23

PULLER

SHAFT
PROTECTOR

JAWS
(10) Loosen coil lead wire from clip on top of com­
pressor front housing (Fig. 8). (11) Remove snap ring and field coil (Fig. 9).

J8924-21

Fig. 6 Shaft Protector

(6)
Insert the lip of the jaws of the rotor puller into
the snap ring groove exposed in the previous step (Fig. 6).
(7) Place rotor puller shaft protector over the ex­
posed shaft.
(8) Install the puller plate and bolt (Fig. 7). 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.
J8924-23

Fig. 8 Loosen Coil Lead Wire

FIELD

COIL
SNAP

RING
J8924-22
J8924-24

Fig. 9 Snap Ring and Field Coil
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.
Fig. 7 Puller Plate

24 - 24
HEATING
AND AIR
CONDITIONING

(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.
(5)
Using Rotor Installer Set, place the ring part of
the set into the bearing cavity (Fig. 10). Make cer­
tain the outer edge rests firmly on the rotor bearing
inner race.
(6) Place the tool set driver into the ring as shown
(Fig. 11).

J8924-25

Fig. 10 Rotor installer Set
J8924-26

Fig. 11 Rotor Installation (7) With a plastic hammer, gently 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.
(a) Check that original clutch shims are in place
on compressor shaft.
(b) Replace compressor shaft key.
(c) Align front plate keyway to compressor shaft
key.
(9) Install front plate assembly.
(10) Using shaft protector, gently tap front plate to
shaft until it has bottomed to the clutch shims (Fig.
12).
Listen for a distinct change of sound during the
tapping process.

J8924-27

Fig. 12 Front Plate to Shaft Installation
(11) Replace shaft hex nut. Tighten the hex nut to
37 N*m (27 ft, lbs.) torque.
(12) Check air gap with feeler gauge. The specifi­
cation is 0.406-0.787 mm (0.016-0.031 inch). If air
gap is not consistent around the circumference,
lightly pry up at the minimum variations (Fig. 13).
Lightly tap down at points of maximum variation.
The air gap is determined by the spacer shims.
When installing the original or a new clutch assem­
bly, try the original shims first. When installing a new clutch onto a compressor that previously did not
have a clutch, use 0.040, 0.020, and 0.005 shims from
the clutch accessory sack.
(13) If the air gap does not meet the specification
given, add or subtract shims as required.

•

HEATING
AND AIR
CONDITIONING
24 - 25

J8924-28
Fig.
13
Check
Air Gap

COMPRESSOR
SHAFT
SEAL

REMOWAL (1) Insert the 2 pins of the front plate spanner into
any 2 threaded holes of the clutch front plate (Fig.

2).
Hold clutch plate stationary. Remove hex nut. (2) Remove clutch front plate using puller. Align
puller center bolt to compressor shaft. Thumb tighten
the 3 puller bolts into the threaded holes.
(3) Turn center bolt clockwise until front plate is
loosened.
Shaft seal replacement should be done on the
bench. Never use any old parts of the shaft seal assembly. Rebuild the complete assembly. (4) Insert the snap ring tool points into the 2 holes
of the felt ring metal retainer and remove felt ring (Fig. 14). (5) Remove the clutch shim. Use O-ring hook and
a small screwdriver to prevent shim from binding on
shaft (Fig. 15).
(6) Remove shaft seal seat retaining snap ring
with pinch type snap ring pliers (Fig. 16). J8924-31

Fig.
16
Snap Ring
Fig.
14 Felt
Ring

24 - 26
HEATING
AND AIR
CONDITIONING

• (7) Remove the shaft seal seat, using seal seat tool
(Fig. 17).
J8924-32

Fig.
17 Shaft
Seal
Seat
(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. 18). Lift out seal assembly.

J8924-33

Fig.
18
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. 19).
J8924-34

Fig.
19 Insert
Seal Sleeve
Protector (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. 20). Twist
tool in opposite direction to disengage tool from seal
cage.
Remove tool.
Fig.
20
Seal Assembly

•

HEATING
AND AIR
CONDITIONING
24 - 27 (6) Coat seal retainer with clean refrigerant oil.
Use seal seat tool to install (Fig. 21). Press lightly against seal.

J8924-36

Fig.
21
Seal
Retainer
(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. 22).

J8924-37

Fig.
22 New
Felt
Ring

(10) Align front plate keyway to compressor shaft
key. (11) Using shaft protector, tap front plate to shaft
until it has bottomed to the clutch shims (Fig. 12).
Listen for a distinct change of sound during the tap­
ping process.
(12) Replace shaft hex nut. Tighten the hex nut to
37 N-m (27 ft. lbs.) torque.
(13) Check air gap with feeler gauge. The specifi­
cation is 0.406-0.787 mm (0.016-0.031 inch). If air
gap is not consistent around the circumference,
lightly pry up at the minimum variations. Lightly
tap down at points of maximum variation.
The air gap is determined by the spacer shims.
When installing the original or a new clutch assem­
bly, try the original shims first. When installing a new clutch onto a compressor that previously did not
have a clutch, use 0.040, 0.020, and 0.005 shims from
the clutch accessory sack.
(14) If the air gap does not meet the specification
given, add or subtract shims as required.

CYLINDER
HEAD
/
VALVE PLATE
REMOVAL
(1) Remove cylinder head bolts.
(2) Using a small hammer and a gasket scraper
separate the cylinder head from the valve plate (Fig.

23).
J8924-39

Fig.
23
Compressor
Cylinder Head