Ball Joints - Upper and Lower

Replace the upper and lower ball joints on the front suspension of a 1972 Ford F-100 with 302 V8, restoring steering geometry and eliminating play in the control arm pivots.

Warnings

Tools required

Parts

• Upper ball joint (driver side) × 1 — Use OEM specification or Moog K772
• Upper ball joint (passenger side) × 1 — Use OEM specification or Moog K772
• Lower ball joint (driver side) × 1 — Use OEM specification or Moog K8695T
• Lower ball joint (passenger side) × 1 — Use OEM specification or Moog K8695T
• Cotter pins (1/8" diameter) × 4 — Assorted pack

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 the ground (do not remove).
4. Apply penetrating oil to all ball joint castle nuts and let soak for 15-30 minutes.
5. Raise front of vehicle and support frame rails with jack stands. Do not place stands under control arms or axle components.
6. Remove front wheels completely.

Procedure

1. 1

   Support lower control arm
   Position floor jack under the I-beam axle near the spindle end. Raise jack until it just contacts the beam and takes a slight load. The coil spring sits between the frame bracket and the I-beam axle, and this jack will control spring tension during disassembly. Keep jack in this position throughout the entire procedure.
2. 2

   Remove brake caliper
   Remove the two bolts securing the brake caliper to the spindle. Lift caliper off the rotor and suspend it from the frame using wire or a bungee cord. Do not let caliper hang by the brake hose as this can damage the hose internally.
3. 3

   Remove hub and rotor assembly
   Remove the dust cap from the center of the hub. Remove the cotter pin and spindle nut. Pull the hub and rotor assembly straight off the spindle. The outer bearing will come with it. Set assembly aside on a clean surface.
4. 4

   Disconnect upper ball joint from spindle
   Remove the cotter pin from the upper ball joint castle nut. Using a wrench, loosen but do not fully remove the castle nut (leave it threaded on 2-3 turns). Strike the spindle boss adjacent to the ball joint stud sharply with a ball peen hammer to break the taper loose. Once the taper releases and the stud pops free, remove the castle nut completely. If hammering does not release the taper after several attempts, use a pickle fork or ball joint separator.
5. 5

   Disconnect lower ball joint from spindle
   Remove the cotter pin from the lower ball joint castle nut. Leave the castle nut threaded on 2-3 turns. Strike the spindle boss at the lower ball joint location to break the taper free. The floor jack supporting the I-beam axle is preventing spring pressure from forcing the components apart. Once taper is broken, carefully lower the floor jack slightly to create clearance, then remove the castle nut. Pivot the spindle assembly upward and out of the way.
6. 6

   Remove upper ball joint from control arm
   On the Twin I-Beam suspension the upper ball joint is pressed into the axle boss (not riveted). Using the ball joint press with appropriate adapters, press the old upper ball joint out of the boss. Remove the old ball joint. Clean the bore with a wire brush. NOTE: Verify against factory service manual whether your specific axle uses press-in or riveted ball joints. Verified detail (The premise that the upper ball joint is riveted is likely incorrect for the Twin I-Beam design, which uses press-in ball joints. The open question should be whether it is press-in at all.): Confirm whether the 1972 Ford F-100 Twin I-Beam upper ball joint is press-fit into the axle boss (expected) or riveted, per the factory service manual. Verified detail (1972 F-100 twin I-beam front suspension typically uses 3 rivets for the upper ball joint, not 4. The openQuestions section even flags this uncertainty.): The upper ball joint is riveted to the upper control arm from the factory. Using a 1/4" or 5/16" drill bit, drill out the 3 rivet heads that secure the ball joint to the control arm.
7. 7

   Install new upper ball joint
   Position the new upper ball joint in the control arm. New ball joints come with bolts and nuts rather than rivets for installation. Insert the 3 bolts from the top side of the control arm through the ball joint. Thread nuts onto bolts from the bottom and tighten evenly to manufacturer specification. The ball joint must seat flush against the control arm. Verified detail (Consistent with step 6 error: the Twin I-Beam upper ball joint is a press-fit into the axle boss, not a bolt-in replacement into a control arm. The bolt/nut installation description is likely wrong for this platform.): Position the new upper ball joint in the axle boss. Using the ball joint press with appropriate adapters, press the new ball joint fully into the bore until the flange seats flush against the axle boss. NOTE: Confirm press-in vs. bolt-in method against the factory service manual for your specific axle.
8. 8

   Remove lower ball joint from control arm
   The lower ball joint is pressed into the lower boss of the I-beam axle. Position the ball joint press tool with the receiving cup on the bottom side of the axle boss and the pressing adapter on top of the ball joint. Tighten the press screw to force the old ball joint out of the axle bore. This requires significant force. Once removed, clean the bore in the axle boss with a wire brush.
9. 9

   Install new lower ball joint
   Position the new lower ball joint in the axle boss bore. Using the ball joint press, install the receiving cup on the bottom to support the axle boss and position the pressing adapter on top of the ball joint body. Tighten the press screw to draw the ball joint into the bore until it is fully seated. The ball joint flange must be flush with the axle boss surface. NOTE: Verify correct ball joint orientation against the factory service manual..
10. 10

    Reconnect spindle to ball joints
    Raise the floor jack under the lower control arm to bring the lower ball joint stud up through the spindle. Thread the castle nut onto the lower ball joint stud and tighten securely. Pivot the top of the spindle toward the upper ball joint and guide the upper ball joint stud through its hole. Thread the castle nut onto the upper ball joint stud and tighten securely. Both castle nuts should be torqued to specification, then tightened further as needed to align cotter pin holes.
11. 11

    Install cotter pins and reassemble hub
    Install new cotter pins through the castle nuts at both ball joints and bend tabs to secure. Slide the hub and rotor assembly back onto the spindle, ensuring the inner bearing is properly seated. Install the outer bearing, spindle washer, and spindle nut. Adjust wheel bearing preload per factory specification (typically tighten to 17-25 ft-lbs while rotating hub, then back off and retighten finger-tight plus 1/8 turn). Install cotter pin and dust cap.
12. 12

    Reinstall brake caliper
    Position the brake caliper over the rotor and align mounting holes. Install the two caliper mounting bolts and tighten securely. Ensure brake hose is not twisted or kinked.
13. 13

    Repeat for opposite side
    Perform steps 1-12 on the opposite front wheel, replacing both upper and lower ball joints following the same procedure. Maintain floor jack support under the lower control arm throughout.

Reassembly

1. Install front wheels and hand-tighten lug nuts.
2. Lower vehicle to ground and remove jack stands.
3. Torque wheel lug nuts to factory specification in a star pattern.
4. Remove wheel chocks.

Verification

• Start engine and turn steering wheel lock-to-lock several times to verify full range of motion without binding.
• Check for any unusual noises from the front suspension during steering movement.
• Test drive vehicle at low speed in a safe area and verify steering response is normal with no pulling or wandering.
• Visually inspect all ball joint connections for proper seating and secure cotter pins.
• Schedule front end alignment immediately, as ball joint replacement affects camber and caster settings.

More procedures for this vehicle