Strut Mount - Front

This procedure addresses replacement of the front suspension upper control arm pivot shaft bushings and mount assembly on a 1972 Ford F-100 with twin I-beam front suspension. Note: This vehicle uses a twin I-beam suspension system, not MacPherson struts.

Warnings

Tools required

Parts

• Upper control arm bushing kit (both sides) × 2 — Use OEM specification or Moog K6121
• Upper ball joint (if worn) × 2 — Moog K778 or equivalent
• Cotter pins (assorted) × 4 — 1/8" diameter

Preparation

1. Park vehicle on level, solid surface and engage parking brake firmly
2. Chock rear wheels securely on both sides
3. Loosen front wheel lug nuts 1/2 turn while vehicle is on ground
4. Raise front of vehicle with floor jack at center of front crossmember
5. Place jack stands under frame rails behind front wheels at solid mounting points
6. Lower vehicle weight onto jack stands, keeping jack in place as backup
7. Remove front wheels completely
8. Spray all suspension fasteners with penetrating oil and allow to soak for at least 15 minutes
9. Visually inspect upper ball joints for excessive wear or torn boots; plan to replace if questionable

Procedure

1. 1

   Mark alignment reference points
   Before disassembly, mark the position of the I-beam axle pivot bushing and any camber adjustment sleeve/bushing relative to its frame bracket, and mark the radius arm position. These marks help preserve approximate alignment. Take photos from multiple angles for reference. Note: final camber/caster on the Twin I-Beam is set with alignment tooling, not by re-indexing eccentric cams.
2. 2

   Support lower control arm
   Position a floor jack with a block of wood on the saddle directly under the lower control arm, just inboard of the coil spring seat. Raise the jack until it just contacts the control arm with light pressure. This will support the coil spring tension once the upper ball joint is disconnected. Do NOT raise the suspension at this point.
3. 3

   Disconnect brake hose bracket
   Locate the flexible brake hose where it connects to the frame or upper control arm. Remove the retaining clip or bolt securing the brake hose bracket to allow sufficient slack for upper control arm movement. Do NOT disconnect the brake line itself; simply free it from its mount.
4. 4

   Remove upper ball joint cotter pin and nut
   Locate the upper ball joint castle nut where the upper control arm connects to the steering knuckle. Remove and discard the cotter pin. Using a socket and breaker bar, remove the castle nut completely. Keep the nut if it is in good condition for potential reuse.
5. 5

   Separate upper ball joint from knuckle
   Using a ball joint separator (pickle fork) or tie rod separator, carefully drive the tool between the upper control arm and the steering knuckle to break the ball joint taper loose. Strike the tool firmly with a hammer until the ball stud releases from the knuckle. WARNING: The knuckle assembly will drop when released, which is why the floor jack must be supporting the lower control arm. If using a pickle fork, be aware this will likely damage the ball joint boot.
6. 6

   Compress coil spring (if necessary)
   If the upper control arm cannot swing clear of the frame with normal suspension droop, carefully install a coil spring compressor on the coil spring according to the tool manufacturer's instructions. Compress the spring only enough to provide clearance for upper control arm removal, typically 1-2 inches. Ensure the compressor is properly seated and tightened evenly before proceeding.
7. 7

   Remove upper control arm pivot shaft nuts
   Locate the large I-beam pivot bolt and nut securing the axle beam to its frame pivot bracket. Apply penetrating oil and remove the pivot nut, then drive out the pivot bolt. Support the beam before it is freed. Note the position of the camber adjustment sleeve/bushing (if fitted) so it can be reinstalled in the same orientation.er each nut.
8. 8

   Remove upper control arm assembly
   With the pivot shaft nuts removed, slide the pivot shaft out of the frame bracket toward the outboard side. You may need to tap the shaft with a rubber mallet or use a pry bar to work it free from the bushings and frame. Once the shaft is free, remove the upper control arm assembly including the shaft, eccentric cams, and washers. Keep all eccentric cams and washers in order.
9. 9

   Inspect and clean frame bracket
   With the upper control arm removed, thoroughly clean the frame bracket pivot holes using a wire brush and brake cleaner. Remove all rust, dirt, and old grease. Inspect the frame bracket for cracks, excessive wear, or elongated holes. Any structural damage requires frame repair before proceeding.
10. 10

    Remove old bushings from control arm
    The upper control arm pivot shaft has pressed-in bushings or may use the shaft itself as the bearing surface with bushings in the frame bracket. If bushings are pressed into the control arm eyes, use a hydraulic press with appropriate adapters to press out the old bushings. Alternatively, if the bushings are in the frame bracket, they will need to be pressed or driven out using a suitable driver.
11. 11

    Install new bushings
    Press new bushings into the upper control arm eyes or frame bracket (depending on design) using a hydraulic press or large C-clamp with appropriate sockets as drivers. Ensure bushings are pressed in straight and fully seated until flush with the control arm or bracket surface. Some bushings require lubrication before installation; follow the bushing manufacturer's instructions.
12. 12

    Reinstall upper control arm assembly
    Position the upper control arm back into the frame bracket with the pivot shaft, eccentric cams, and washers in their original orientation (reference your alignment marks and photos). Insert the pivot shaft through the frame bracket and control arm, aligning the eccentric cams with your reference marks. Thread both nuts onto the shaft ends by hand.
13. 13

    Reconnect upper ball joint to knuckle
    Swing the upper control arm downward and align the ball joint stud with the hole in the steering knuckle. You may need to raise or lower the floor jack supporting the lower control arm to align the taper. Once aligned, thread the castle nut onto the ball joint stud and tighten it snugly. Do not torque yet.
14. 14

    Remove spring compressor and settle suspension
    If a coil spring compressor was installed, carefully and evenly loosen and remove it now. Slowly raise the floor jack under the lower control arm to bring the suspension to normal ride height. This loads the bushings in their operating position before final torquing.
15. 15

    Torque all fasteners
    With the suspension at normal ride height (jack supporting vehicle weight through lower control arm): Torque the I-beam pivot bolt/nut and radius arm fasteners to factory specification (verify against a 1972 F-100 shop manual — these are large fasteners, typically over 100 ft-lb; exact specification required). Torque the ball joint (or king pin) castle nut to the factory specification for the 1972 F-100 Twin I-Beam (verify exact value against the shop manual before final torque). Install a new cotter pin through the castle nut and ball joint stud, bending the ends to secure. Reattach the brake hose bracket.

Reassembly

1. Reinstall wheels and hand-tighten lug nuts in a star pattern
2. Raise vehicle slightly to remove jack stands
3. Lower vehicle to ground carefully
4. Torque wheel lug nuts to 100-140 ft-lb in a star pattern with vehicle on ground
5. Repeat entire procedure for opposite side if required

Verification

• With vehicle on ground, bounce front end several times and listen for any unusual noises or looseness
• Visually inspect all fasteners to confirm proper installation and torque
• Check that brake hose has adequate slack through full steering travel without binding
• Verify cotter pins are properly installed and bent on ball joint nuts
• Test drive vehicle at low speed in a safe area, checking for unusual handling, vibration, or noise
• MANDATORY: Schedule professional wheel alignment immediately; vehicle is not safe for normal operation until alignment is verified

More procedures for this vehicle