Torsion Bar

Replacement of front torsion bar suspension components on a 1972 Ford F-100, including removal and installation of torsion bars, adjusting arms, and associated hardware.

Warnings

Tools required

Parts

• Torsion bar (left or right as needed) × 1 — Use OEM specification
• Torsion bar adjusting bolt kit × 1 — Use OEM specification
• Lower control arm bushings (if worn) × 2 — Use OEM specification
• Torsion bar crossmember bushings (if worn) × 2 — Use OEM specification
• Anti-seize compound × 1 — High-temperature rated

Preparation

1. Park vehicle on level surface and chock rear wheels securely
2. Measure and record ride height from ground to bottom of frame rail at multiple points for reference
3. Apply penetrating oil to torsion bar adjustment bolt, crossmember mounting bolts, and lower control arm pivot bolts. Allow to soak for at least 30 minutes
4. Raise front of vehicle with floor jack and support securely on jack stands under frame rails behind lower control arms
5. Remove front wheels for improved access
6. Mark torsion bar adjusting bolt position by counting exposed threads and marking adjustment arm position relative to crossmember

Procedure

1. 1

   Document torsion bar adjustment position
   Count and record the number of threads visible on the torsion bar adjusting bolt. Measure the distance from the adjusting arm to the crossmember. Use paint pen to mark the adjusting arm position relative to the crossmember bracket. These measurements are critical for restoring proper ride height after reassembly.
2. 2

   Release torsion bar tension
   Install torsion bar unloading tool onto the adjusting arm and crossmember bracket according to tool manufacturer instructions. Turn the tool slowly to transfer load from the adjusting bolt to the tool. Once load is transferred, the adjusting bolt should turn freely. Remove the adjusting bolt completely, then slowly release tension on the unloading tool in a controlled manner. Keep hands and body clear of the tool during release.
3. 3

   Remove lower shock absorber mounting
   Locate the lower shock absorber mounting bolt at the lower control arm. Remove the bolt and hardware securing the shock to the lower control arm. Allow the shock to hang freely or support it with wire to prevent strain on upper mounting.
4. 4

   Disconnect lower control arm from crossmember
   Locate the lower control arm rear pivot bolt at the torsion bar crossmember. Support the lower control arm with a floor jack to prevent sudden drop. Remove the pivot bolt nut and drive the bolt out using a hammer and punch if necessary. Lower the control arm slowly and allow it to hang from the upper ball joint.
5. 5

   Remove torsion bar adjusting arm
   With tension released, slide the adjusting arm off the rear end of the torsion bar. The arm should slide off with moderate effort. If stuck, use penetrating oil and light taps with a dead blow hammer. Note the orientation and any alignment marks on the arm splines for reassembly.
6. 6

   Mark torsion bar orientation
   Before removing the torsion bar, mark the front and rear ends clearly to identify which end faces forward and which side (left or right) the bar came from. Torsion bars have directional winding and are side-specific. Also mark the clocking position of the bar relative to the lower control arm socket using a paint pen across both components.
7. 7

   Remove torsion bar from lower control arm
   Working from the rear, slide the torsion bar rearward out of the lower control arm socket. The bar should slide out with moderate effort once all tension is released. If the bar is stuck, use a brass drift and hammer to tap it rearward. Do not use excessive force or damage to the bar ends or control arm socket may occur. Some bars have a retaining clip at the front that must be removed first.
8. 8

   Inspect and clean mounting points
   Thoroughly inspect the torsion bar crossmember bushings, lower control arm socket, and all mounting hardware for wear, cracking, or damage. Clean all splined surfaces and sockets with a wire brush. Inspect the removed torsion bar for cracks, deep corrosion pitting, or damage. Replace any worn components before reassembly.
9. 9

   Prepare new torsion bar for installation
   Verify the new torsion bar is correct for the side being serviced (left or right bars are not interchangeable). Clean the splined ends of the new bar with solvent and allow to dry. Apply a thin coat of anti-seize compound to all splined surfaces to aid future removal and prevent corrosion. Do not use excessive amounts as it may affect spline engagement.
10. 10

    Install torsion bar into lower control arm
    Align the front splined end of the torsion bar with the lower control arm socket. Match any clocking marks if installing the original bar. Slide the bar forward into the socket until fully seated. The bar should insert smoothly without forcing. If resistance is encountered, verify correct orientation and alignment of splines. Ensure any retaining clips are properly installed if equipped.
11. 11

    Install adjusting arm onto torsion bar
    Slide the adjusting arm onto the rear splined end of the torsion bar. Align the arm so the adjusting bolt hole points downward and matches the crossmember bracket position. The arm should slide on with hand pressure. If necessary, use a dead blow hammer to tap it into position. Do not force the arm onto incorrect splines.
12. 12

    Reconnect lower control arm to crossmember
    Raise the lower control arm into position using a floor jack. Align the control arm rear pivot with the crossmember mount. Insert the pivot bolt and install the nut. Tighten the pivot bolt nut to proper torque specification with vehicle weight on suspension (final torque after vehicle is lowered).
13. 13

    Reinstall lower shock absorber mounting
    Position the shock absorber to the lower control arm mounting point. Insert the mounting bolt and hardware. 52.0 lb-ft (70.0 Nm) Verified detail (Exact torque specification for lower shock absorber mounting bolt on 1972 Ford F-100): 52.0 lb-ft (70.0 Nm)
14. 14

    Apply initial tension to torsion bar
    Install the torsion bar unloading tool onto the adjusting arm and crossmember. Apply tension to the tool to compress the adjusting arm upward toward the crossmember bracket. While holding tension, thread the adjusting bolt into the crossmember until it contacts the adjusting arm. Continue turning the bolt while releasing tool tension to transfer load from tool to bolt. Remove the unloading tool once load is fully transferred to the adjusting bolt.
15. 15

    Set initial ride height adjustment
    Turn the adjusting bolt to approximately match the position documented during disassembly. Use the thread count and paint marks as reference. This is a preliminary setting only. Final ride height adjustment must be performed with vehicle at curb weight on level ground.

Reassembly

1. Reinstall front wheels and torque lug nuts to specification in a star pattern
2. Lower vehicle to ground and bounce front suspension several times to settle components
3. Measure ride height and compare to pre-disassembly measurements
4. Adjust torsion bar tension by turning adjusting bolt clockwise to raise or counterclockwise to lower ride height
5. Torque lower control arm pivot bolt to specification with vehicle weight on suspension
6. After 50-100 miles of driving, recheck ride height and retighten all fasteners

Verification

• Verify ride height matches pre-service measurements or manufacturer specifications (typically 2-3 inches from ground to lowest point of lower control arm at ball joint)
• Test drive vehicle and verify normal handling with no pulling, vibration, or unusual noises from front suspension
• Confirm both front wheels are at equal height when viewed from front of vehicle
• Schedule front end alignment to verify camber, caster, and toe settings after torsion bar service

More procedures for this vehicle