1995 ISUZU TROOPER Workshop Manual

COMPRESSOR OVERHAUL 1 D - 1
SECTION 10
COMPRESSOR OVERHAUL
CONTENTS
General Description . . . . . . . . . . . . . . . . . . . . . 1 D-1
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
D-2
General Information . . . . . . . . . . . . . . . . . . . . 1 D-3
Compressor Oil . . . . . . . . . . . . . . . . . . . . . . 1 D-3
Service Procedures . . . . . . . . . . . . . . . . . . . . . 1D-5
Magnetic Clutch Assembly . . . . . . . . . . . . . 1 D-5
Main Data and Specifications . . . . . . . . . . . . . 1 D-8
General Specifications . . . . . . . . . . . . . . . . . 1 D-8
Torque Specifications . . . . . . . . . . . . . . . . . 1 D-8
Special Tools . . . . . . . . . . . . . . . . . . . . . . . . . . 1D-9
GENERAL DESCRIPTION
When servicing the compressor, keep dirt or foreign
material from getting on or into the compressor
parts and system. Clean tools and a clean work area
are
important for proper service. The compressor
connections and the outside of the compressor
should be cleaned before any "On-Vehicle" repair,
or before removal of the compressor. The parts must
be kept clean at all times and any parts to be
reassembled
should be cleaned with Trichloro­
ethane, naphtha, kerosene, or equivalent solvent,
and
dried with dry air. Use only lint free cloths to
wipe parts.
The
operations described below are based on bench
overhaul
with compressor removed from the
vehicle, except as noted. They have been prepared
in
order of accessibility of the components. When
the compressor is removed from the vehicle for
servicing, the oil remaining in the compressor
should be discarded and new compressor oil added
to the compressor.
Magnetic clutch assembly repair procedures require
that the system be discharged of refrigerant. (Refer
to Section 1 B for "REFRIGERANT RECOVERY".)
Compressor malfunction will appear in one of four
ways: noise, seizure, leakage or low discharge
pressure. Resonant
compressor noises are not
cause for alarm; however, irregular noise or rattles
may indicate broken parts or excessive clearances
due to wear. To check seizure, de-energize the
magnetic clutch and check to see if the drive plate
can be rotated.
If rotation is impossible, the com­
pressor is seized. Low discharge pressure may be
due to a faulty internal seal of the compressor, or a
restriction in the compressor.
Low discharge pres­
sure
may also be due to an insufficient refrigerant
charge
or a restriction elsewhere in the system.
These possibilities
should be checked prior to
servicing the compressor. If the compressor is
inoperative,
but is not seized, check to see if current
is being supplied to the magnetic clutch coil
terminals.
This vehicle is equipped with five-vane rotary com­
pressor.
The
compressor has vanes built into a rotor which is
mounted on a shaft.
When the shaft rotates, the vanes built into the
cylinder block assembly are opened by centrifugal
force.
This changes the volume of the space formed by the
rotor and cylinder, resulting in the intake and
compression of the refrigerant gas. The discharge
valve and the
valve stopper, which protects the
discharge valve, are
built into the cylinder block
assembly. There is no suction valve but a shaft seal
is
installed between the shaft and head; a trigger
valve, which applies back pressure to the vanes, is
installed in the cylinder block and a refrigerant gas
temperature sensor is installed in the front head.
The specified
quantity of compressor oil is contained
in
the compressor to lubricate the various parts
using
the refrigerant gas discharge pressure.
The thermo sensor is installed to the front head of
the compressor to protect it by stopping its
operation when the refrigerant gas is insufficient or
when the temperature get abnormally high.
•OFF ..... 160 ±soc (320.0 ± 9.0°F)
•ON ..... 135 ±soc (275.0 ± 9.0°F)
The oil used in the HFC-134a system compressor
differs from that used in R-12 systems.
Also, compressor
oil to be used varies according to
the compressor model. Be sure to avoid mixing two
or more different types of oil.
If the wrong oil is used, lubrication will be poor and
the compressor will seize or malfunction.
The specified
amount of the compressor oil is
150cc (5.0 fl.oz.).

1 D-2 COMPRESSOR OVERHAUL
Fig. 1 D-1
DIAGNOSIS
ITEM PROBLEM POSSIBLE CAUSES CORRECTION
1
Noise from compressor 1. Defective rotor Replace compressor
2. Defective shaft Replace compressor
2 Noise
from magnetic 1. Defective bearing Replace magnetic clutch
clutch
face 2. Defective clutch Replace magnetic clutch
3. Clearance
between drive plate and pulley Replace magnetic clutch
not standard or adjust
the clearance
3
Insufficient cooling 1. Defective gasket Replace
compressor
2. Defective rotor Replace compressor
3. Defective trigger valve Replace compressor
4 Not rotating 1. Defective rotor Replace compressor
2. Defective shaft Replace compressor
3. Rotating parts seized due to insufficient oil Replace compressor
5 Oil and/or gas leakage 1. Defective seal Replace compressor
2. Defective 0-ring Replace
•

COMPRESSOR OVERHAUL 10-3
GENERAL INFORMATION
COMPRESSOR OIL
OIL SPECIFICATION
• The HFC-134a system requires a synthetic
(PAG) compressor oil whereas the R-12 system
requires a
mineral compressor oil. The two oils
must never be mixed.
• Compressor (PAG) oil varies according to com­
pressor model. Be sure to use oil specified for
the model of compressor.
• Always use HFC-134a Vane Rotary Type Com­
pressor Oil
(AIPDN Part No. 2-90188-301-0)
HANDLING OF OIL
• The oil should be free from moisture, dust,
metal powder, etc.
• Do not mix with other oil.
•
The water content in the oil increases when
exposed to the air. After use, seal oil from air
immediately.
(HFC-134a Vane Rotary Compressor Oil absorbs
moisture very easily.)
•
The compressor oil must be stored in steel
containers, not in plastic containers.
COMPRESSOR OIL CHECK
The oil used to lubricate the compressor is circul­
ating with the refrigerant.
Whenever replacing any component of the system
or a large amount of gas leakage occurs, add oil to
maintain the original amount of oil.
Oil Capacity.
Capacity
total in system 150cc (5.0 fl.oz.)
Compressor (Service
parts)
charging amount 15 0cc (5
·0
fl.oz.)
Checking and Adjusting for Used Compressor
1. Perform Oil return operation.
(Refer to "Oil Return Operation" in this section.)
2. Discharge and recover refrigerant and remove
the compressor.
3. Drain the compressor oil and measure the
extracted oil with a measuring cylinder (Fig. 1 D-
2).
Fig. 1D-2
4. If the amount of oil drained is much less than
90cc (3.0 fl.oz.), some refrigerant may have
leaked out. Conduct leak tests on connections of
each system, and if necessary, repair or replace
faulty parts.
5. Check the compressor oil for contamination.
(Refer to "Contamination of Compressor Oil" in
this section.)
6. Adjust oil level following the procedure below
(Fig. 1 D-3).
Collected Amount
more than 90cc
(3.0 fl.oz.)
Charging Amount
same as collected amount
less than 90cc (3.0 fl.oz.) 90cc (3.0 fl.oz.)
7. Install the compressor, then evacuate, charge
and
perform oil return operation.
8. Check system operation.
When it is impossible to perform oil return oper­
ation, the compressor oil should be checked in the
following order:
1. Discharge and recover refrigerant and remove
the compressor.
2. Drain the compressor oil and measure the
extracted oil with a measuring cylinder.
3. Check the oil for contamination.
4. If more than 90cc (3.0 fl.oz.) of oil is extracted
from the compressor, supply same amount of
oil to the compressor to be installed.
If
the amount of oil extracted is less than 90cc
(3.0 fl.oz.),
recheck the compressor oil in the
following order:
5. Supply 90cc (3.0 fl.oz.) of oil to the compressor
and install it onto the vehicle.