AC Compressor Clutch

Remove and replace the AC compressor clutch assembly on a 1970 AMC Rebel Machine with 390ci V8 engine.

Warnings

Tools required

Parts

• AC compressor clutch assembly × 1 — Use OEM specification for York or Tecumseh compressor
• Clutch coil (if equipped separately) × 1 — Use OEM specification
• Snap ring (shaft retaining) × 1 — Use OEM specification
• Shims for air gap adjustment × 1 — Assorted thickness 0.015-0.030 inch

Preparation

1. Park vehicle on level ground and engage parking brake
2. Disconnect negative battery cable to prevent accidental clutch engagement
3. Allow engine to cool completely if recently operated
4. Verify compressor clutch failure by checking for physical damage, bearing noise, or electrical continuity at clutch coil
5. Take photos of belt routing and electrical connections for reference

Procedure

1. 1

   Remove drive belts
   Loosen the alternator and power steering pump adjustment bolts. Pivot accessories toward engine block to create slack in drive belts. Remove all belts that contact the AC compressor pulley. Note the belt routing for reinstallation.
2. 2

   Disconnect clutch coil electrical connector
   Locate the wire connector at the compressor clutch coil. Disconnect the electrical connector by pulling it straight off the coil terminal. On some applications, remove the small retaining screw securing the wire terminal to the coil.
3. 3

   Remove clutch hub snap ring
   Use snap ring pliers to remove the large snap ring securing the clutch hub to the compressor shaft. The snap ring sits in a groove on the compressor shaft forward of the clutch hub. Carefully expand the ring and lift it off the shaft, being careful not to scratch the shaft surface.
4. 4

   Remove clutch hub and drive plate
   With the snap ring removed, grasp the clutch hub assembly and pull it straight off the compressor shaft. If the hub is tight on the shaft, use a two or three jaw puller positioned behind the hub. Do not strike the hub with a hammer as this may damage the compressor shaft seal. Remove the drive plate shims from behind the hub and keep them together for air gap measurement.
5. 5

   Remove pulley and bearing assembly snap ring
   Locate the outer snap ring that retains the pulley and bearing assembly to the compressor nose. This snap ring sits in a groove on the compressor housing. Use snap ring pliers to compress and remove this retaining ring.
6. 6

   Remove pulley and bearing assembly
   With the outer snap ring removed, grasp the pulley firmly and pull it straight off the compressor nose. The pulley assembly includes the bearing and outer housing. If stuck, use a puller positioned behind the pulley. Inspect the bearing for roughness or noise by spinning it by hand.
7. 7

   Remove clutch coil
   The electromagnetic coil is retained to the compressor housing by screws or bolts around its perimeter. Remove all fasteners securing the coil assembly. Carefully pull the coil straight off the compressor nose. Note any shims or spacers behind the coil for reinstallation.
8. 8

   Clean mounting surfaces
   Use a wire brush to clean the compressor shaft, nose, and all mounting surfaces. Remove any rust, debris, or old lubricant. Inspect the shaft for scoring or damage. Check the shaft seal for leakage. Clean the mating surface on the new clutch components.
9. 9

   Install new clutch coil
   Position the new electromagnetic coil over the compressor nose with wire terminal oriented in the original position. Install any original shims behind the coil. Install and tighten the coil retaining fasteners evenly in a cross pattern. Verify coil is seated flush against the compressor housing.
10. 10

    Install pulley and bearing assembly
    Slide the new or cleaned pulley and bearing assembly over the compressor nose and coil. Push it firmly into position until it seats against the shoulder. Install the outer snap ring in its groove, ensuring it is fully seated around the entire circumference. Verify the pulley spins freely without binding.
11. 11

    Install clutch hub with initial air gap setting
    Place the original shim pack on the compressor shaft. Slide the clutch hub and drive plate assembly onto the shaft, pressing it firmly against the shims. Install the shaft snap ring in its groove, ensuring full engagement. The air gap between clutch surfaces must be checked and adjusted.
12. 12

    Check and adjust clutch air gap
    Using feeler gauges, measure the gap between the pulley face and the clutch drive plate at three points around the circumference. The air gap should be 0.015 to 0.030 inches (consult specific compressor specifications). If gap is incorrect, remove hub snap ring and add or remove shims as needed. Each 0.010 inch shim changes gap by approximately 0.010 inch. Recheck gap after adjustment.
13. 13

    Reconnect clutch coil electrical connector
    Attach the electrical connector to the clutch coil terminal. If equipped with a screw-type terminal, secure the wire terminal with its retaining screw. Verify the connection is clean and tight. Test coil resistance with multimeter if available (typical reading 3-5 ohms).
14. 14

    Reinstall drive belts
    Route drive belts according to original configuration or reference photos. Position belts on compressor pulley and all other pulleys. Adjust alternator and power steering pump positions to achieve proper belt tension. Belt should deflect approximately 1/2 inch under moderate thumb pressure at the longest span.

Reassembly

1. Reconnect negative battery cable
2. Verify all fasteners are tight and electrical connections are secure
3. Double-check drive belt routing and tension before starting engine

Verification

• Start engine and turn AC controls to maximum cooling
• Listen for clutch engagement click and verify clutch hub pulls in against pulley face
• Check for abnormal noise from compressor or clutch bearing
• Verify clutch disengages when AC is turned off
• Confirm cooling system begins to produce cold air (system must be properly charged)
• Inspect for proper belt operation without slippage or squealing

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