AC Clutch Coil

Remove and replace the AC compressor clutch coil on a 1966 Chevrolet Corvette with 327ci V8 engine, including drive belt removal and electrical connector service.

Warnings

Tools required

Parts

• AC compressor clutch coil × 1 — Use OEM specification for York or Frigidaire compressor
• AC compressor drive belt × 1 — Reuse if in good condition
• Electrical connector (if corroded) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake.
2. Disconnect negative battery cable to prevent electrical shorts during coil replacement.
3. Allow engine and AC compressor to cool completely if vehicle was recently operated.
4. Verify compressor type (York or Frigidaire) by inspecting compressor casting for identification markings.
5. Photograph or diagram the AC compressor drive belt routing for reference during reinstallation.

Procedure

1. 1

   Remove AC compressor drive belt
   Locate the AC compressor at the front of the engine; on the 1966 Corvette 327 it is typically mounted on the passenger side. Verify location on your vehicle. Loosen the compressor mounting bracket adjustment bolt and pivot bolt to create slack in the drive belt. Slip the belt off the compressor pulley, then off its remaining drive pulleys per the routing diagram you made during disassembly. Remove belt from engine bay. Remove belt from engine bay.
2. 2

   Disconnect clutch coil electrical connector
   Locate the electrical connector(s) attached to the clutch coil; configuration (single-wire case-grounded vs two-wire) varies between York and Frigidaire compressors, so verify before disconnecting. The connector is typically a spade-type terminal with a rubber boot. Pull the rubber boot back and carefully pull the connector straight off the coil terminal. If connector is corroded, gently work it free with a flat screwdriver, taking care not to damage the terminal.
3. 3

   Remove clutch pulley snap ring
   Using snap ring pliers, locate the snap ring that retains the clutch pulley assembly to the compressor nose. The snap ring sits in a groove on the compressor shaft, visible at the center of the clutch pulley. Carefully expand the snap ring and remove it from the groove. Control the snap ring to prevent it from springing away.
4. 4

   Remove clutch pulley and bearing assembly
   With the snap ring removed, grasp the clutch pulley firmly with both hands and pull it straight off the compressor shaft. The pulley assembly includes the bearing and will slide off as a unit. If tight, gently tap the back of the pulley with a rubber mallet while pulling outward. Set the pulley assembly aside on a clean work surface.
5. 5

   Remove clutch plate shim pack
   Behind the pulley assembly, you will find a series of thin shims that control clutch air gap. These shims are loose and will fall if not caught. Carefully remove and count all shims, keeping them in order. Note the total thickness or number of shims for reinstallation reference.
6. 6

   Remove clutch friction plate
   The clutch friction plate (driven plate) is splined to the compressor shaft and held by a snap ring. Using snap ring pliers, remove the snap ring from the shaft groove. Once the snap ring is removed, slide the friction plate off the splined compressor shaft. Inspect the friction surface for wear, glazing, or oil contamination.
7. 7

   Remove clutch coil retaining hardware
   The clutch coil is retained to the compressor nose by 3 screws or bolts arranged in a circular pattern. Using the appropriate socket or screwdriver, remove all 3 fasteners in a criss-cross pattern to prevent binding. Keep fasteners organized for reinstallation.
8. 8

   Extract clutch coil from compressor
   With fasteners removed, carefully pull the clutch coil straight off the compressor nose. The coil fits over a central hub and may require slight wiggling to free it. Inspect the coil mounting surface on the compressor nose for debris, corrosion, or damage. Clean with a wire brush if necessary.
9. 9

   Install new clutch coil
   Position the new clutch coil over the compressor nose hub, aligning the mounting holes with the threaded holes in the compressor body. Ensure the electrical terminal is positioned for easy access and clear of moving components. Seat the coil fully against the compressor nose face.
10. 10

    Install clutch coil retaining hardware
    Install the 3 retaining screws or bolts through the coil and thread them into the compressor body. Tighten in a criss-cross pattern to ensure even seating of the coil. Snug fasteners firmly but do not overtighten, as this can distort the coil housing and cause failure.
11. 11

    Install clutch friction plate
    Slide the clutch friction plate onto the splined compressor shaft with the friction surface facing outward (toward the pulley side). Ensure the plate is fully seated on the splines. Install the snap ring into the shaft groove to retain the friction plate, ensuring the snap ring is fully seated in the groove.
12. 12

    Install clutch plate shim pack
    Install the original shim pack over the compressor shaft, positioning them between the friction plate and the location where the pulley bearing will sit. Use the same number and thickness of shims that were removed. Proper shimming is critical for correct clutch air gap.
13. 13

    Install clutch pulley and bearing assembly
    Align the clutch pulley assembly with the compressor shaft and slide it onto the shaft, compressing the shims. Push the pulley assembly firmly until it bottoms against the shims. Install the snap ring into the shaft groove to retain the pulley assembly, ensuring the snap ring is fully seated.
14. 14

    Verify and adjust clutch air gap
    Using a feeler gauge, measure the air gap between the friction plate and the pulley face at 3 points around the circumference. The gap should be 0.015 to 0.030 inches. If gap is incorrect, remove pulley and snap ring, then add or remove shims as needed. Adjust shim quantity per the compressor manufacturer's service manual to achieve the specified gap; verify shim direction-of-effect for your specific York or Frigidaire unit before adding or removing shims.
15. 15

    Reconnect electrical connector and install drive belt
    Push the electrical connector firmly onto the clutch coil terminal until it seats completely. Position the rubber boot over the connection. Route the AC compressor drive belt according to the diagram made during disassembly. Pivot the compressor outward and tighten the adjustment bolt to achieve proper belt tension (approximately 1/2 inch deflection at mid-span with firm thumb pressure). Tighten the pivot bolt.

Reassembly

1. Reconnect negative battery cable.
2. Start engine and turn on AC system to verify clutch engagement. You should hear a distinct click when the AC is switched on, and the clutch should engage smoothly without squealing or chattering.
3. Verify drive belt tracking is correct and belt is not contacting any brackets or components.

Verification

• With engine running and AC off, verify that clutch pulley freewheels (spins) while compressor shaft remains stationary.
• Turn AC system on and verify clutch engages with an audible click. Friction plate should lock to pulley and rotate compressor shaft.
• Check for abnormal noises such as squealing, grinding, or rattling during clutch engagement and operation.
• Verify AC system operates and begins cooling within normal time frame, indicating compressor is being driven properly.
• Inspect clutch coil electrical connection for security and proper seating of rubber boot.

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