A/C Compressor Clutch - Repeat Failures
87chrysler4Models
1985 & 1986 Domestic Vehicles
Subject
A/C Clutch Failure
Index
AIR CONDITIONING
Date
June 2, 1986
No.
24-02-86
P-2031
This bulletin is issued to clarify the application of the A/C clutch and pulley, and supply additional diagnostic information on A/C clutch failures. There are two types of clutches and pulleys available for service. The new style "stepped" pulley is to be used ONLY with the new style "stepped" clutch coil assembly.
SYMPTOM/CONDITION
Repeat failure of the air conditioning clutch and pulley assembly. The failure will appear to be a burned out condition that occurs for no apparent reason, after all specifications were correct at the time of installation. The clutch contact area will generally have a bluish or burned metal appearance, with no indication of compressor shaft seal oil leakage.
CORRECTIVE ACTION
Carefully inspect the FAILED pulley assembly prior to discarding it, to verify that it is either a "stepped" or "nonstepped" pulley assembly. If the pulley assembly is a "stepped" pulley, it should have had a "stepped" clutch coil assembly installed behind it.
If inspection reveals that a "stepped" pulley assembly has been installed over a "non-stepped" clutch coil assembly, this is probably what caused the failure.
The IMPROVED STEPPED CLUTCH AND COIL design was developed to increase the application pressure and reduce slipping of the A/C clutch when it is engaged. Using the "stepped" clutch assembly with the "non-stepped" clutch coil reduces the clutch apply pressure which causes the assembly to fail.
FIGURE 1:
The "non-stepped" pulley assembly will NOT fit over the "stepped" coil assembly; however, the "stepped" pulley assembly WILL fit over the "nonstepped" coil assembly.
DO NOT USE THE "STEPPED" PULLEY ASSEMBLY IN COMBINATION WITH THE "NON-STEPPED" CLUTCH COIL ASSEMBLY (FIGURE 1).
A/C CLUTCH FAILURE DIAGNOSIS
A/C Clutch Noisy
1. Using your hands or suitable tool between the front of the compressor and the clutch coil assembly, determine if the coil assembly is loose.
2. If the clutch is loose, remove the assembly and determine that the snap ring was installed properly, and seated in the groove.
3. If the snap ring was installed correctly and the clutch assembly is still loose, check the alignment pin in the compressor. If the alignment pin hole in the coil assembly is elongated, or the pin is loose, replace the compressor front cover and the clutch/coil assemblies.
4. When installing the new parts, make sure that the snap ring is installed with the beveled edge facing out or away from the compressor. Positioning of the snap ring is important. Be sure that the "eyes" of the snap ring are NOT lined up with the coil retaining pin, they MUST be positioned either to the right or left of the pin.
NOTE: BE SURE THE NEW COIL ASSEMBLY IS TIGHT TO THE COMPRESSOR. IF THE COIL IS LOOSE AT THE TIME OF INSTALLATION, ENGINE VIBRATIONS WILL CAUSE THE COMPRESSOR FRONT CASE TO WEAR AWAY AND THE CLUTCH FAILURE WILL REPEAT.
A/C CLUTCH SLIPPING OR BURNED
1. Using Miller Tool C-4563 on the clutch pulley, rotate the compressor shaft. If the compressor will NOT rotate, it has seized, and will have to be replaced.
2. If the compressor can be rotated, remove the pulley assembly and inspect the friction surfaces.
3. If the friction surfaces are oily, or show signs of contamination, inspect the compressor shaft seal area for a leak. Remove the "felt" from the nose of the compressor and inspect for oil. A small amount of oil on the back of the felt is acceptable. If the felt is saturated with oil, the shaft seal has failed and MUST BE REPLACED.
4. If the compressor shaft seal is OK, locate and correct the source of the oil contamination (compressor head bolt, front cover porosity, fuel pump gasket, valve cover gasket, refrigerant line, head gasket, etc.).
5. If the friction surfaces are dry, the coil is probably partially shorted and will have to be replaced.
2. Using a feeler gauge inserted between the front plate and the pulley face, measure the clearance. It should be 20-35 thousanths of an inch around the entire surface of the clutch.
3. If the clearance is NOT correct, it MUST be corrected by installing the proper shims between the coil assembly and the front plate. (Refer to the shop manual for shim installation.)
A/C CLUTCH DOES NOT OPERATE
1. Connect a jumper from the battery to the clutch and check for operation. If the clutch does NOT operate, it is open circuit and will have to be replaced.
2. If the clutch DOES operate, check to see that the current draw does not exceed 5 amperes. If the current draw DOES exceed 5 amperes, the clutch is shorted and must be replaced.
3. Reconnect the clutch to the vehicle wiring, and install jumpers across the low pressure cut-out switch and the clutch cycling switch.
4. Push the A/C button and place the fan switch in "high blow."
5. Start the vehicle and allow for time delay.
6. If the clutch does NOT engage, check the system fuse, the push button switch, or the clutch/fan relay.
7. If the clutch does engage, remove the jumpers one at a time and reconnect the wiring to the switch. If the clutch disengages when the jumper is removed for the switch, the switch is defective and must be replaced. If the clutch engages with the low pressure cut-out switch jumpered, check for low charge and correct. If the charge is not low, replace the low pressure cut-out switch.
NOTE: ANY TIME THE CLUTCH IS ENGAGED, THE A/C FAN MUST BE RUNNING. IF IT DOES NOT COME ON, THE FAN, FAN RELAY, OR WIRING ARE DEFECTIVE AND MUST BE CORRECTED.
CLUTCH BURNISHING PROCEDURE
After a new clutch and pulley assembly has been installed, cycle the clutch at least 20 cycles at 5 second intervals. For example: 5 seconds on, five seconds off 20 times.
POLICY: Information only