Compressor Clutch: Service and Repair

The content of this article reflects the changes called out by TSB 26-12-00.

The refrigerant system can remain fully-charged during compressor clutch, pulley, or coil replacement. The compress or clutch can be serviced in the vehicle.

REMOVAL
1. Disconnect an isolate the battery negative cable.
2. Remove the serpentine drive belt.
3. Unplug the compressor clutch coil wire harness connector.
4. Remove the clutch plate and the clutch shims. If necessary, tap the clutch plate lightly with a plastic hammer to loosen it.

CAUTION: Do not pry between the clutch plate and the clutch pulley to remove the plate. Failure to observe this caution may result in damage to the compressor clutch assembly.

5. Remove the compressor clutch pulley retaining snap ring with snap ring pliers.
6. Remove the clutch pulley assembly from the compressor. A 3 jaw puller can be used to remove pulley. Shaft protector # MC-91211 must be used to protect compressor shaft from damage. Do not allow puller's center screw to bear on compressor shaft. If necessary, tap the clutch pulley lightly with a plastic hammer to loosen it.
7. Remove the screw and retainer from the clutch coil lead wire harness on the compressor front housing.
8. Unplug the compressor clutch wire harness connectors from the thermal limiter switch.
9. Note the alignment of the clutch field coil assembly on the compressor before removing it for correct reinstallation.

Clutch/Pulley/Coil Remove/Install - Typical:

10. Remove the snap ring that secures the clutch field coil assembly to the compressor front housing.
11. Remove the clutch field coil assembly from the compressor front housing

INSPECTION
Examine the friction surfaces of the clutch pulley and the front plate for wear. The pulley and front plate should be replaced if there is excessive wear or scoring.

If the friction surfaces are oily, inspect the shaft and nose area of the compressor for oil. If excessive oil is present, the shaft seal is leaking and the compressor must be replaced.

Check the clutch pulley bearing for roughness or excessive leakage of grease. Replace the bearing, if required.

INSTALLATION
1. Position the back of the clutch field coil against the compressor front housing. Be certain that the locating pin on the back of the coil lines up with the indentation on the compressor front housing. This ensures the proper orientation of the coil and the wire harness.
2. Install the clutch field coil snap ring (bevel side outward) with snap ring pliers. Be certain that the snap ring is properly seated into 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 front housing of the compressor.

3. Install the clutch coil lead wire harness retaining clip on the compressor front housing and tighten the retaining screw.
4. Plug in the compressor clutch wire harness connectors to the thermal limiter switch.
5. Position the clutch pulley assembly onto the compressor.

CAUTION: Do not mar or contaminate the clutch pulley friction surface.

6. Install the clutch pulley assembly snap ring (bevel side outward) with snap ring pliers. Be certain that the snap ring is properly seated in the groove.
7. Place a trial stack of shims, 0.07 mm (0.027 inch) thick, on the compressor shaft.

Aligning Clutch Plate Splines - Typical:

8. Note the machined mating splines on the compressor shaft and in the clutch plate hub.
9. Align the mating splines and install the clutch plate on the compressor shaft.
10. Install the external front rotor snap ring with snap ring pliers. The bevel side of the snap ring must be facing outward. Press the snap ring to make sure it is properly seated in the grove.

Check Clutch Air Gap - Typical:

11. With the front clutch plate assembly tight against the shims, measure the air gap between the clutch plate and the pulley face with a feeler gauge. The air gap should be from 0.35 to 0.65 mm (0.013 to 0.025 inch). If the proper air gap is not obtained, add or subtract shims until the desired air gap is obtained.
12. Install the compressor shaft nut. Tighten the nut to 17.7 Nm (13 ft. lbs).
13. The shims may compress after tightening the compressor shaft nut. Check the air gap in four or more places to verify that the air gap is still correct. Spin the pulley for a final check.
14. Reverse the remaining removal procedures to complete the installation.

Clutch Break-In
After a new compressor clutch has been installed, cycle the compressor clutch approximately twenty times (five seconds on, then five seconds off). During this procedure, set the heater-A/C control to the recirculation mode (Max-A/C), the blower motor switch in the highest speed position, and 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.