This procedure covers the removal and replacement of the AC compressor clutch assembly on a 1966 Chevrolet Corvette with 327ci V8 engine, including belt removal, electrical disconnect, and clutch hub service.

Warnings

Tools required

Parts

• AC compressor clutch assembly × 1 — Use OEM specification for Harrison compressor
• Compressor drive belt × 1 — Use OEM specification
• Clutch coil (if faulty) × 1 — Use OEM specification for Harrison compressor

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine to cool completely
3. Disconnect battery negative terminal
4. Verify AC system is off and depressurized (clutch should be disengaged)
5. Inspect compressor for oil leaks that would indicate shaft seal failure
6. Take photos of belt routing and electrical connections for reference

Procedure

1. 1

   Remove compressor drive belt
   Locate the compressor drive belt on the front of the engine. On the 1966 Corvette 327, the AC compressor is typically mounted low on the passenger side of the engine. Using a pry bar or adjustable wrench on the tensioner, release belt tension and slip the belt off the compressor pulley. Remove belt from all pulleys and set aside.
2. 2

   Disconnect clutch coil electrical connector
   Locate the single wire electrical connector attached to the compressor clutch coil. This connector typically has a bullet-style or spade terminal. Disconnect the wire from the coil terminal and move it aside to prevent interference. Note the routing for reinstallation.
3. 3

   Remove clutch hub retaining nut
   The clutch hub is secured to the compressor shaft with a retaining nut in the center of the pulley assembly. Using the appropriate clutch hub holding tool or pin spanner to prevent the hub from rotating, remove the retaining nut. This nut typically has 7/16" hex or requires a specialized spanner. Turn counterclockwise to remove. Keep the nut and any washers in a safe location.
4. 4

   Remove clutch hub assembly
   With the retaining nut removed, use a clutch hub puller to remove the clutch hub from the compressor shaft. Thread the puller into the hub's threaded center hole and tighten the center screw to draw the hub off the shaft. The hub is press-fit onto the shaft with a key or drive slot. Apply steady pressure until the hub releases. Remove the hub and inspect the shaft keyway for damage.
5. 5

   Remove clutch coil retaining snap ring
   With the clutch hub removed, you now have access to the clutch coil assembly. Locate the snap ring that retains the clutch coil in the pulley/rotor assembly. Using snap ring pliers, carefully remove this snap ring from its groove in the compressor front housing. Keep the snap ring in a safe location for reinstallation.
6. 6

   Remove pulley and bearing assembly
   The pulley/rotor assembly is held to the compressor front head by 3 bolts. Using the appropriate socket, remove these 3 bolts and carefully pull the pulley assembly straight off the compressor nose. The bearing is typically pressed into the pulley. Inspect the bearing for roughness or noise by spinning it by hand. If bearing is worn, the entire pulley assembly should be replaced.
7. 7

   Remove and inspect clutch coil
   The electromagnetic clutch coil sits inside the pulley assembly. Carefully remove the coil from the pulley housing. Inspect the coil for physical damage, burning, or broken wires. Using a multimeter, check coil resistance across the terminals. A typical Harrison compressor clutch coil should read between 3.0 and 4.0 ohms. If reading is infinite (open circuit) or significantly outside this range, replace the coil.
8. 8

   Clean and inspect all components
   Clean the compressor shaft, pulley bearing surfaces, and all mating surfaces with a wire brush and shop towels. Remove any rust, dirt, or old lubricant. Inspect the compressor shaft for scoring or wear. Inspect the clutch hub friction surface for glazing, cracks, or excessive wear. Check the pulley rotor face for heat damage or warping. Replace any damaged components.
9. 9

   Install new or serviced clutch coil
   Place the new or tested clutch coil into the pulley housing, ensuring proper seating and orientation. The wire terminal should be positioned for easy access once installed. Ensure the coil sits flush in its recess in the pulley assembly.
10. 10

    Install pulley and bearing assembly
    Carefully align the pulley/rotor assembly onto the compressor front head, ensuring the coil wiring is routed properly and not pinched. Install the 3 retaining bolts and tighten in a cross pattern to ensure even seating. Since no torque specification is provided, tighten securely to approximately 10-15 ft-lbs, being careful not to overtighten and strip the aluminum housing threads.
11. 11

    Install clutch coil snap ring
    Using snap ring pliers, install the clutch coil retaining snap ring into its groove in the compressor housing. Ensure the snap ring is fully seated in the groove around its entire circumference. This secures the coil assembly.
12. 12

    Install clutch hub assembly
    Clean the compressor shaft and the inside bore of the new or serviced clutch hub. Align the keyway or drive slot in the hub with the key or slot on the compressor shaft. Carefully slide the hub onto the shaft, ensuring proper engagement. The hub should slide on with moderate resistance. If equipped with a key, ensure it is properly seated in the shaft keyway before installing the hub.
13. 13

    Install and torque clutch hub retaining nut
    Install any washers and the clutch hub retaining nut onto the compressor shaft threads. Using the hub holding tool to prevent rotation, tighten the retaining nut. Since no torque specification is provided, tighten securely to approximately 15-20 ft-lbs, ensuring the hub is fully seated against the shaft shoulder.
14. 14

    Measure and verify clutch air gap
    Using a feeler gauge, measure the air gap between the clutch hub friction surface and the pulley rotor face at 3 equally spaced points around the circumference. The air gap should be 0.015" to 0.030" on Harrison compressors. If the gap is too large, check for proper hub installation and shaft condition. If gap is too small, the clutch may drag. This measurement is critical for proper clutch engagement.
15. 15

    Reconnect electrical connector and install drive belt
    Reconnect the clutch coil electrical wire to the terminal on the coil. Ensure a secure connection. Route the belt according to the original routing diagram, placing it around the compressor pulley last. Apply tension using the appropriate tensioner or adjustment method. Belt should have approximately 1/2" deflection when pressed firmly at the longest span between pulleys. Reconnect battery negative terminal.

Reassembly

1. Ensure clutch air gap is within specification before final belt installation
2. Verify all electrical connections are secure and properly routed away from moving components
3. Double-check that snap ring is fully seated and all fasteners are tight
4. Confirm drive belt is properly seated on all pulleys and tensioned correctly

Verification

• Start the engine and observe the compressor pulley. It should rotate freely without noise or wobble.
• Turn on the AC system and verify clutch engagement. You should hear an audible click and see the clutch hub engage with the pulley.
• With AC running, listen for any abnormal noises from the compressor area indicating bearing failure or improper installation.
• Check for proper cooling system operation. AC should blow cold air within 2-3 minutes of engagement.
• Turn AC off and verify clutch disengages cleanly without continued rotation of the hub.
• Recheck drive belt tension after 15-20 minutes of operation, as new belts may seat and stretch slightly.

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