Torsion Bar

Complete removal and replacement of the front suspension torsion bar(s) on a 1966 Corvette, including disassembly of related suspension components and proper preload adjustment.

Warnings

Tools required

Parts

• Torsion bar (left or right as needed) × 1 — Use OEM specification or equivalent rated bar
• Torsion bar bushings (crossmember) × 1 — Use OEM specification
• Torsion bar arm seals × 1 — Use OEM specification
• Lower control arm shaft bushings (if worn) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake.
2. Chock rear wheels securely.
3. Loosen front wheel lug nuts while vehicle is on ground.
4. Raise front of vehicle with floor jack at front crossmember jacking point.
5. Place jack stands under frame rails behind front suspension crossmember.
6. Lower vehicle onto jack stands ensuring stable support.
7. Remove front wheels completely.
8. Apply penetrating oil to all suspension fasteners to be removed and allow to soak for 15-20 minutes.
9. Measure and record ride height from ground to bottom of lower control arm at ball joint for reference during reassembly.

Procedure

1. 1

   Mark torsion bar adjustment position
   Before removing tension, measure the exact position of the torsion bar adjusting bolt. Use a tape measure to record the distance from the end of the adjusting bolt to the torsion bar adjuster arm, or count and record the number of threads visible beyond the adjuster arm nut. Mark the adjuster arm position with a scribe or marker for reference during reinstallation. This measurement is critical for maintaining proper ride height.
2. 2

   Install torsion bar removal tool
   Position the torsion bar removal tool (Kent-Moore J-7450 or equivalent) onto the torsion bar adjusting arm. The tool should seat firmly against both the crossmember and the adjusting arm. Ensure the tool's threaded shaft is centered on the adjusting arm before proceeding. Verify the tool is stable and properly aligned.
3. 3

   Load torsion bar tool
   Using the breaker bar, turn the torsion bar tool's center screw clockwise to apply pressure to the adjusting arm. Tighten the tool until it takes up all slack and you feel resistance. The adjusting arm should be slightly compressed against the tool. Do not overtighten - you only need enough pressure to unload the adjusting bolt.
4. 4

   Remove torsion bar adjusting bolt
   With the tool supporting the load, use a wrench to remove the torsion bar adjusting bolt and lock nut from the adjusting arm. The bolt should come out freely since the tool is supporting the spring tension. Remove the adjusting bolt completely and set aside. Count the number of turns required to remove it for reference.
5. 5

   Release torsion bar tension
   Very slowly turn the torsion bar tool's center screw counterclockwise to gradually release the stored tension in the torsion bar. Release tension in small increments, approximately 1/4 turn at a time. The adjusting arm will slowly move as tension is released. Continue until all tension is released and the adjusting arm is fully relaxed. Remove the torsion bar tool.
6. 6

   Disconnect strut rod from lower control arm
   Locate the strut rod connection at the front of the lower control arm. Remove the 2 nuts and bolts securing the strut rod bracket to the lower control arm. The strut rod will remain attached to the front crossmember. Push the strut rod forward and out of the way to provide clearance for torsion bar removal.
7. 7

   Remove lower shock absorber mounting
   Locate the lower shock absorber mounting bolt at the lower control arm. Remove the single nut and bolt securing the shock absorber to the lower control arm. The shock will remain hanging from the upper mount - secure it out of the way with wire or a bungee cord to prevent damage.
8. 8

   Disconnect lower ball joint
   Remove the cotter pin from the lower ball joint castle nut. Loosen but do not fully remove the castle nut - leave it threaded on 2-3 turns to protect the threads. Using a ball joint separator (pickle fork or tie rod puller), break the taper loose between the ball joint stud and the steering knuckle. Once the taper is broken, remove the castle nut completely and separate the lower control arm from the steering knuckle. Support the steering knuckle assembly with wire to prevent strain on the brake hose.
9. 9

   Remove lower control arm pivot shaft
   Locate the lower control arm pivot shaft at the front crossmember. The shaft runs through the crossmember and is secured by 2 bolts with nuts (one on each side of the crossmember). Remove both nuts and bolts completely. Note that these bolts also secure the control arm shaft in the crossmember bushings. Tap the shaft with a rubber mallet to break it free if necessary, then slide the entire lower control arm and shaft assembly rearward out of the crossmember to provide access to the torsion bar.
10. 10

    Remove torsion bar from crossmember
    The torsion bar extends rearward from the lower control arm through the crossmember. From underneath the vehicle, locate the torsion bar where it passes through the crossmember bushing. Note the orientation markings on the end of the bar (typically stamped 'L' for left or 'R' for right). Using a rubber mallet, carefully tap the front end of the torsion bar (at the lower control arm end) to drive it rearward through the crossmember. The bar should slide out through the rear of the crossmember. If the bar is stuck, apply penetrating oil and use gentle tapping. Remove the bar completely from the vehicle.
11. 11

    Inspect and clean torsion bar mounting points
    With the torsion bar removed, inspect the crossmember bushing for wear, cracking, or deterioration. Inspect the lower control arm hex socket where the torsion bar seats for damage or deformation. Use a wire brush to clean all rust, dirt, and old grease from the crossmember bushing bore, the lower control arm hex socket, and the torsion bar adjuster arm area. Inspect the torsion bar adjusting arm rubber seal and replace if torn or deteriorated.
12. 12

    Prepare and install new or replacement torsion bar
    Verify the replacement torsion bar is correct for the side being serviced (left or right marking). Apply a generous coating of white lithium grease or chassis grease to the entire length of the torsion bar, paying special attention to the hex ends. Apply grease inside the crossmember bushing and the lower control arm hex socket. Insert the torsion bar into the crossmember from the rear, pushing it forward through the bushing. Align the hex end with the hex socket in the lower control arm and push the bar fully forward until it seats completely in the lower control arm. The bar should be fully engaged in both the crossmember bushing and the control arm socket.
13. 13

    Reinstall lower control arm pivot shaft
    Position the lower control arm with the torsion bar attached back into the front crossmember. Slide the control arm pivot shaft through the crossmember bushings and through the control arm eyes. Install both pivot shaft bolts and nuts finger tight only. Do not torque these fasteners yet - they must be torqued at ride height. Ensure the control arm moves freely through its arc of travel.
14. 14

    Reconnect lower ball joint to steering knuckle
    Position the steering knuckle over the lower ball joint stud. Install the castle nut and tighten to specification (typically 50-60 ft-lb for this application, but verify with shop manual). Install a new cotter pin through the castle nut and ball joint stud. Bend the cotter pin ends to secure. The ball joint taper should be fully seated in the steering knuckle.
15. 15

    Reconnect strut rod and shock absorber
    Position the strut rod bracket back onto the lower control arm. Install the 2 bolts and nuts securing the strut rod to the lower control arm and tighten finger tight only - these will be torqued at ride height. Reconnect the lower shock absorber mount to the lower control arm. Install the bolt and nut and tighten to specification (typically 15-20 ft-lb).
16. 16

    Install torsion bar adjustment tool and preload bar
    Install the torsion bar removal tool onto the adjusting arm as in Step 2. Turn the tool's center screw clockwise to compress the adjusting arm until you can reinstall the torsion bar adjusting bolt. Thread the adjusting bolt back into the adjusting arm to the approximate position recorded in Step 1 (using your thread count or measurement). Install the lock nut finger tight. Slowly release tension on the tool by turning the center screw counterclockwise, allowing the torsion bar to take up the load. Remove the tool once all tension is released.
17. 17

    Set preliminary ride height adjustment
    Using your initial measurements from preparation, adjust the torsion bar adjusting bolt to achieve approximately the same ride height as before. Turn the adjusting bolt clockwise to increase ride height or counterclockwise to decrease it. This is a preliminary setting - final adjustment will be made after the vehicle is at curb weight. Tighten the lock nut against the adjuster arm to hold the setting.
18. 18

    Reinstall wheel and lower vehicle to ride height
    Reinstall the front wheel and tighten lug nuts in a star pattern to specification (verify with the 1966 Corvette Chassis Service Manual, typically around 65-75 ft-lb). Raise the vehicle slightly with the floor jack to remove weight from the jack stands. Remove jack stands from under the frame. Slowly lower the vehicle until the tires contact the ground but the suspension is not fully loaded. Bounce the front end several times to settle the suspension.
19. 19

    Torque suspension fasteners at ride height
    With the vehicle at normal ride height and weight on the suspension, torque all suspension fasteners that were loosened. Torque the lower control arm pivot shaft bolts to specification (typically 65-75 ft-lb). Torque the strut rod mounting bolts to specification (typically 30-35 ft-lb). This ensures bushings are not pre-loaded in a twisted state.
20. 20

    Final ride height adjustment and wheel torque
    Measure ride height from level ground to the bottom of the lower control arm at the ball joint. Compare to the measurement taken during preparation. Adjust the torsion bar adjusting bolt as needed to achieve proper ride height (typically 7-8 inches from ground to lower control arm ball joint centerline for stock ride height). Make adjustments in small increments, bouncing the suspension after each adjustment. Once ride height is correct, torque the wheel lug nuts to final specification (80-90 ft-lb) in a star pattern.

Reassembly

1. All suspension fasteners must be torqued to specification at ride height to prevent bushing bind and premature wear.
2. Both sides should have equal ride height measurements when complete. If replacing only one bar, compare to the opposite side.
3. After 50-100 miles of driving, recheck ride height and make fine adjustments if needed as the bar seats.
4. Check all fasteners for proper torque after the first test drive.

Verification

• Measure ride height on both sides - should be within 1/4 inch of each other and match factory specifications.
• Bounce each front corner of the vehicle - suspension should rebound smoothly without binding or unusual noises.
• Verify all suspension fasteners are torqued to specification and no loose hardware remains.
• Test drive vehicle at low speed and verify steering returns to center properly and no pulling occurs.
• Inspect for any fluid leaks around shock absorbers after test drive.
• After 50 miles, re-torque wheel lug nuts and recheck ride height measurements.

More procedures for this vehicle