Remove and replace the upper control arm on a 1966 Chevrolet Corvette with 327ci V8, including disconnecting ball joint and removing mounting bolts from frame.

Warnings

Tools required

Parts

• Upper control arm assembly × 1 — Use OEM specification or aftermarket equivalent
• Upper ball joint (if not included with control arm) × 1 — Use OEM specification
• Upper control arm shaft nuts × 2 — Reuse if in good condition
• Ball joint castle nut × 1 — Reuse if threads are good
• Cotter pin × 1 — 1/8 inch diameter

Preparation

1. Park vehicle on level, solid surface and engage parking brake
2. Place wheel chocks behind rear wheels
3. Loosen front wheel lug nuts while vehicle is on ground
4. Raise front of vehicle with floor jack at factory frame jacking point
5. Place jack stands under front frame rails behind lower control arms
6. Lower vehicle onto jack stands and verify stability
7. Remove front wheel completely

Procedure

1. 1

   Support lower control arm
   Position floor jack under lower control arm near ball joint to support suspension load. Raise jack until it just makes contact but does not lift the vehicle. This maintains spring tension during disassembly and prevents sudden movement.
2. 2

   Remove ball joint cotter pin and castle nut
   Remove the cotter pin from the upper ball joint castle nut using pliers or side cutters. Unscrew the castle nut from the ball joint stud but leave it threaded on 2-3 turns to catch the spindle when the taper releases.
3. 3

   Separate upper ball joint from spindle
   Using a ball joint separator (pickle fork or press-type tool), break the taper connection between the upper ball joint stud and the steering spindle. Strike the separator firmly with a hammer if using pickle fork type, or apply steady pressure if using press type. Once taper releases, remove castle nut completely and lift ball joint stud out of spindle.
4. 4

   Mark shim locations
   Before removing control arm, note the position and number of alignment shims at each mounting bolt location (front and rear). The front and rear positions may have different shim stacks. Mark or photograph their locations to maintain approximate alignment during reassembly.
5. 5

   Remove front upper control arm shaft nut
   Remove the two front cross-shaft attaching bolts (or nuts on the shaft studs) securing the upper control arm cross shaft to the frame crossmember. Keep track of all alignment shims and washers, noting their exact locations.
6. 6

   Remove rear upper control arm shaft nut
   Repeat the process for the rear upper control arm mounting nut. Remove the nut, washers, and note all shim positions. If nuts are seized, apply penetrating oil and allow to soak before applying additional force.
7. 7

   Remove upper control arm shaft bolts
   With the cross-shaft attaching bolts removed and the shims captured, lower the upper control arm and cross shaft assembly away from the frame crossmember. Do not lose or scramble the alignment shim stacks.
8. 8

   Remove upper control arm
   With both shafts removed, carefully lower the upper control arm away from the frame brackets. Maneuver it clear of the suspension components and spindle. Inspect frame bracket bushings for wear or damage while arm is removed.
9. 9

   Inspect and prepare new control arm
   Compare new upper control arm to old unit to verify correct application. Inspect ball joint boot for damage and ensure grease fitting is present and clear. If ball joint is separate, install it to the control arm per manufacturer instructions before installation.
10. 10

    Install new upper control arm
    Position new upper control arm into frame brackets. Insert front control arm shaft through frame bracket and arm bushings, ensuring proper alignment. Install shims in their original positions (or per alignment specifications if known). Thread on washers and nut finger-tight. Repeat for rear shaft.
11. 11

    Connect ball joint to spindle
    Raise the upper control arm ball joint stud into the steering spindle hole. Install castle nut and tighten to the factory specification (verify exact value in the 1963-1967 Corvette Shop Manual before final torque). The nut should draw the taper tight into the spindle. Align castle nut slots with hole in ball joint stud and install new cotter pin, bending ends to secure.
12. 12

    Torque control arm mounting nuts
    Before final torque, support the suspension at ride height by raising a jack under the lower control arm/spindle until the suspension is loaded to its normal ride position. Then torque the upper control arm cross-shaft attaching bolts to the factory specification (verify exact value in the 1963-1967 Corvette Shop Manual). Do not final-torque while the suspension hangs at full droop as this will bind the bushings.
13. 13

    Final inspection and reassembly
    Remove floor jack from under lower control arm. Verify all fasteners are secure and cotter pin is properly installed. Reinstall wheel, hand-tighten lug nuts. Raise vehicle slightly, remove jack stands, and lower vehicle to ground. Torque wheel lug nuts to the factory specification in a star pattern (verify exact value in the 1963-1967 Corvette Shop Manual).

Reassembly

1. Always install a new cotter pin on the ball joint castle nut
2. Torque all suspension fasteners with vehicle at ride height, not at full droop
3. Original shim configuration provides starting point for alignment but professional alignment is required after control arm replacement
4. Grease upper ball joint through fitting after installation if equipped

Verification

• Verify cotter pin is properly installed and bent through ball joint castle nut
• Confirm both upper control arm shaft nuts are torqued to specification
• Check that upper ball joint moves smoothly without binding when turning steering wheel
• Verify no unusual noises when bouncing front suspension
• Schedule wheel alignment immediately after repair to verify camber and caster settings

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