Compressor Clutch: Service and Repair

The refrigerant system can remain fully charged during compressor clutch, pulley or coil replacement. Although the compressor assembly must be removed from the mounting bracket, the compressor clutch can be service with the compressor in the vehicle.

REMOVAL
1. Disconnect and isolate the battery negative cable.
2. Raise and support the vehicle.
3. Remove the serpentine drive belt. Refer to Cooling System for the proper procedures.

Fig.40 A/C Compressor Remova/Install:

4. Disconnect the engine wire harness connectors from the compressor clutch coil connector and the high pressure cut out switch.
5. Loosen the four screws that secure the compressor to the lower front strut-to-engine bracket.
6. Remove all of the compressor mounting screws except the upper left (rear of the compressor) screw and tilt the front (pulley end) of the compressor downward far enough to access the clutch for removal. The upper left screw remains loosely installed to support the compressor during clutch service.

Fig.41 Compressor Shaft Bolt And Clutch Plate:

7. Remove the compressor shaft bolt. A band-type oil filter wrench or a strap wrench can be placed around the clutch plate to aid in bolt removal.

Fig.42 Clutch Plate And Shim(s):

8. Tap the clutch plate lightly with a plastic hammer and remove clutch plate and shim(s). Be certain not to lose the shim or shims.

CAUTION: Do not pry between the clutch plate unit and the pulley to remove the clutch plate from the compressor shaft as this may damage the clutch plate.

Fig.43 Remove Clutch Pulley Snap Ring:

9. Remove the external snap ring securing the pulley to the front cover of the compressor with snap ring pliers, and slide the pulley OFF of compressor.
10. Remove the screw that secures the clutch coil pigtail wire connector bracket and ground clip to the top of the compressor housing.

Fig.44 Remove Clutch Coil Snap Ring:

11. Remove the external snap ring securing the clutch coil to the front cover of the compressor with snap ring pliers, and slide the clutch coil off of the compressor.

INSPECTION
1. Examine the friction surfaces of the clutch pulley and the clutch plate for wear. The pulley and clutch plate should be replaced if there is excessive wear or scoring.
2. Examine the friction surfaces of the clutch pelley and the clutch plate for oil contamination. If the friction surfaces are oily, inspect the shaft and nose area of the compressor for oil. Remove the felt packing from around the compressor shaft in the compressor front cover. If the felt is saturated with oil, the shaft seal is leaking and the compressor will have to be replaced.
3. Check the clutch pulley bearing for roughness or excessive leakage of grease. Replace the bearing, if required.

INSTALLATION
1. Align the dowel pin on the back of the clutch coil with the hole in the compressor front cover, and position the clutch coil onto the compressor. Be certain that the clutch coil pigtail wires are properly oriented and routed so that they are not pinched between the compressor front cover and the clutch coil.

NOTE: A new snap ring must be used to secure the clutch coil to the compressor. The bevel side of the snap ring must face outward.

2. Install the external snap ring securing the clutch coil to the front cover of the compressor with snap ring pliers. Be certain that the snap ring is fully and properly seated in the groove.

CAUTION: If the snap ring is not fully seated in the groove it will vibrate out, resulting in a clutch failure and severe damage to the compressor front cover.

3. Install and tighten the screw that secures the clutch coil pigtail wire connector bracket and ground clip to the top of the compressor housing.

Fig.45 Install Clutch Pulley:

4. Install the pulley onto the front cover of the compressor. If necessary, tap the pulley gently with a block of wood placed on the pulley friction surface.

CAUTION: Do not mar the friction surfaces of the pulley.

5. Install the external snap ring (bevel side facing outward) securing the clutch pulley to the front cover of the compressor with snap ring pliers. Be certain that the snap ring is fully and properly seated in the groove.
6. If the original clutch plate and clutch pulley are to be reused, reinstall the original shim(s) on the compressor shaft against the shoulder. If a new clutch plate and/or clutch pulley are being used, install a trial stack of shims 2.54 mm (0.10 in.) thick on the compressor shaft against the shoulder.
7. Install the clutch plate onto the compressor shaft.
8. Install and tighten the compressor shaft bolt. A band-type oil filter wrench or a strap wrench can be placed around the clutch plate to aid in bolt tightening. Tighten the bolt to 17.5 Nm (155 in. lbs.).
9. If a new clutch plate and/or clutch pulley are being used, the air gap between the clutch plate and clutch pulley must be checked using the following procedure:
a. Attach a dial indicator to the compressor front cover so that the movement of the clutch plate can be measured.
b. With the dial indicator zeroed on the clutch plate, energize the clutch and record the measurement of the clutch plate movement.
c. The correct reading is 0.35 to 0.65 mm (0.014 to 0.026 in.). If the correct reading is not obtained, add or subtract shims until the desired reading is obtained.

NOTE: The shims may compress after tightening the compressor shaft bolt. Check the air gap in four or more places on the clutch plate to verify that the air gap is still correct. Spin the clutch pulley before making the final air gap check.

10. Install and tighten the four screws that secure the compressor to the Tower front strut-to-engine bracket.Tighten the screws to 28.3 Nm (250 in. lbs.).
11. Reconnect the engine wire harness connectors to the compressor clutch coil connector and the high pressure cut out switch.
12. Reinstall the serpentine drive belt. Refer to Cooling System for the proper procedures.
13. Lower the vehicle.
14. Reconnect the battery negative cable.

Clutch Break-in
After a new compressor clutch has been installed, cycle the compressor clutch about twenty times (five seconds ON, then five seconds OFF). During this procedure, set the heater-A/C control to the A/C mode, the blower switch in the highest speed position and hold the engine speed at 1500 to 2000 rpm. This procedure (burnishing) will seat the opposing friction surfaces and provide a higher compressor clutch torque capability.