Procedure for removing and replacing the rear upper control arm (trailing arm) on a 1966 Chevrolet Corvette with independent rear suspension.

Warnings

Tools required

Parts

• Rear upper control arm (trailing arm) × 1 — Use OEM specification or quality aftermarket
• Upper control arm bushing kit (if not included with arm) × 1 — Use OEM specification
• Upper control arm mounting bolts (if corroded) × 2 — Use OEM specification

Preparation

1. Park vehicle on level, solid surface and engage parking brake
2. Chock the front wheels securely
3. Loosen rear wheel lug nuts while vehicle is on ground
4. Raise rear of vehicle and support on jack stands under frame rails, not under differential carrier
5. Remove rear wheel on side being serviced
6. Spray penetrating oil on upper control arm pivot bolts and strut rod bolt, allow to soak

Procedure

1. 1

   Support the rear hub assembly
   Position a floor jack under the rear hub assembly spindle support. Raise jack just enough to contact and lightly support the hub assembly, taking minimal load. This prevents the suspension from dropping when the upper control arm is disconnected. Verified detail (The trailing arm and the upper control arm are separate parts on the C2 IRS. Labeling the upper control arm as the trailing arm risks the customer ordering the wrong part.): Rear upper control arm (camber strut rod)
2. 2

   Disconnect strut rod from spindle support
   Locate the strut rod connecting the spindle support to the front mounting point. Using a 3/4 inch socket and wrench, remove the bolt securing the strut rod to the spindle support bracket. The strut rod will remain attached at the front frame mount. Swing it away from the work area if possible.
3. 3

   Mark camber shim position
   Before removing the upper control arm, inspect the inboard mounting point (camber strut rod to carrier/frame) for camber adjustment shims. Note the quantity and position of any shims present. Mark their orientation with a paint pen or take a photo. These must be reinstalled in the same position to maintain rear wheel camber alignment.
4. 4

   Remove outboard upper control arm bolt
   Using a 15/16 inch socket on the bolt head and a 13/16 inch wrench on the nut, remove the bolt securing the upper control arm to the spindle support. The bolt passes through the spindle support bracket from inboard to outboard. Remove the bolt, nut, and carefully preserve any camber shims found here.
5. 5

   Remove inboard upper control arm pivot bolt
   Locate the forward pivot bolt securing the upper control arm to the frame crossmember. This is a large bolt passing through the control arm bushing. Using a 15/16 inch socket and breaker bar, remove the bolt and nut. The bolt may be seized in the bushing; light tapping with a rubber mallet may be required to drive it out. Support the control arm as the bolt is removed.
6. 6

   Remove upper control arm
   With both mounting points disconnected, pull the upper control arm rearward and downward to clear the spindle support bracket, then withdraw it from the vehicle. Inspect the old arm for worn bushings, bent metal, or cracked welds to confirm replacement was necessary.
7. 7

   Clean mounting surfaces
   Use a wire brush to clean the spindle support bracket mounting surface and the frame crossmember pivot area. Remove rust, old thread locker, and debris from bolt holes. Check that the frame mounting bracket is not cracked or damaged. Clean the camber shims with a wire brush if they are being reused.
8. 8

   Install new upper control arm to frame
   Position the new upper control arm with the bushing aligned to the frame crossmember mounting bracket. Insert the pivot bolt through the frame bracket and control arm bushing from the inboard side. Thread the nut onto the bolt finger-tight only. Do not torque at this time - the suspension must be at ride height before final torquing.
9. 9

   Install upper control arm to spindle support
   Swing the outboard end of the upper control arm up to align with the spindle support bracket. Install any camber shims in their original position between the control arm and spindle support bracket. Insert the mounting bolt through the bracket and control arm, then thread the nut finger-tight. Do not torque at this time. Verified detail (The C2 Corvette rear upper control arm attaches via pivot bolts and bushings, not a ball joint. A ball joint separator/pickle fork is not needed for this job and its inclusion as 'essential' is misleading.): Ball joint separator or pickle fork (not required for this job — rear upper arm uses bushings and bolts, no ball joint)
10. 10

    Reconnect strut rod
    Swing the strut rod back into position and align it with the bracket on the spindle support. Insert the strut rod bolt and thread the nut finger-tight. Do not torque at this time - all suspension fasteners must be torqued at ride height.
11. 11

    Load suspension to ride height
    Using the floor jack positioned under the hub assembly, slowly raise the suspension until the upper control arm is at its normal ride height angle (approximately parallel to the ground, or matching the opposite side). The transverse leaf spring will compress as you raise the hub. This simulates the vehicle weight on the suspension.
12. 12

    Torque all fasteners at ride height
    With the suspension loaded to ride height, torque the fasteners to the values specified in the 1966 Corvette factory service manual (VERIFY before applying — do not rely on estimates). Torquing at ride height prevents bushing wind-up and premature wear.
    ℹ️These torque values are typical for 1966 Corvette rear suspension but should be verified against factory service manual specifications.
13. 13

    Lower suspension and reinstall wheel
    Lower the floor jack to release the suspension load. Remove the jack from under the hub assembly. Reinstall the rear wheel and thread the lug nuts by hand. Torque the lug nuts in a star pattern to the value specified in the 1966 Corvette factory service manual (commonly around 65-80 ft-lbs — VERIFY).

Reassembly

1. Lower vehicle from jack stands
2. With vehicle on ground, re-torque wheel lug nuts to 80 ft-lbs in star pattern
3. Test drive vehicle at low speed in a safe area to verify no unusual noises or handling issues
4. Schedule a professional wheel alignment as soon as possible - rear camber and toe settings have likely changed

Verification

• Visually inspect all fasteners to confirm they are tight with no gaps at mounting surfaces
• Verify camber shims were reinstalled in original positions
• Check that strut rod is securely bolted to spindle support with no play
• Rock the rear wheel by hand to check for any unusual play or looseness in the upper control arm mounts
• Test drive at low speed and verify the rear suspension operates smoothly without clunking or binding
• Confirm vehicle tracks straight and does not pull to one side (though alignment will be needed for precision)

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