This procedure covers the removal and replacement of the front upper control arm on a 1970 AMC Rebel Machine, including ball joint separation and bushing considerations.

Warnings

Tools required

Parts

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

Preparation

1. Park vehicle on level surface and apply 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 frame rail or designated jacking point
5. Support vehicle securely on jack stands placed under frame rails behind front suspension
6. Remove front wheel and tire assembly
7. Spray all upper control arm fasteners with penetrating oil and allow to soak

Procedure

1. 1

   Support lower control arm
   Position a floor jack under the lower control arm to support the weight of the suspension and maintain pressure on the coil spring. Raise jack just enough to slightly compress the spring but do not lift the vehicle off the jack stands. This prevents the suspension from dropping when the upper ball joint is disconnected.
2. 2

   Remove upper ball joint cotter pin
   Locate the upper ball joint castle nut at the top of the steering knuckle. Straighten and remove the cotter pin from the castle nut. If the cotter pin is corroded, cut it with diagonal cutters and extract the pieces.
3. 3

   Loosen upper ball joint castle nut
   Using a 9/16 inch socket, loosen the upper ball joint castle nut but do not remove it completely. Leave the nut threaded on the stud several turns to prevent the control arm from separating violently when the taper breaks free.
4. 4

   Separate ball joint from spindle
   Insert a ball joint separator or pickle fork between the upper control arm and the steering knuckle. Strike the separator firmly with a hammer to break the tapered connection. Once the taper breaks free, remove the castle nut completely and separate the upper ball joint stud from the knuckle. Allow the knuckle assembly to pivot downward, supported by the lower control arm.
   ⚠The knuckle will drop suddenly when the ball joint releases. Ensure the floor jack is properly supporting the lower control arm.
5. 5

   Mark control arm position
   Before removing the control arm, use a scribe or paint pen to mark the position of the control arm shaft nuts relative to the mounting bracket. This will help preserve the existing alignment settings during reassembly. Note the number of threads showing on each shaft end and the orientation of any shims.
6. 6

   Remove front control arm shaft nut
   Using a 3/4 inch socket and breaker bar, remove the nut from the front control arm shaft. Hold the shaft from rotating if necessary using a second wrench on the flats. Note the presence and position of any washers or shims and keep them with the corresponding bolt.
7. 7

   Remove rear control arm shaft nut
   Using a 3/4 inch socket and breaker bar, remove the nut from the rear control arm shaft. Again note any washers, shims, or spacers and their orientation. The control arm should now be free to remove from the vehicle.
8. 8

   Remove upper control arm assembly
   Pull the control arm shafts out from the frame mounting bracket. The control arm assembly can now be removed from the vehicle. If the shafts are seized in the bushings or frame bracket, tap them gently with a brass drift or use a pry bar to work the arm free. Inspect the frame mounting bracket for damage or excessive wear.
9. 9

   Prepare new control arm
   If installing a new control arm assembly, compare it to the old unit to ensure correct fitment. Check that the ball joint is properly installed and torqued if it came separately. Clean the control arm shaft threads with a wire brush. Apply a light coat of anti-seize compound to the shaft threads.
10. 10

    Install new upper control arm
    Position the new upper control arm assembly into the frame mounting bracket. Insert both control arm shafts through the frame bracket bushings. Install any original shims in their original positions based on your earlier markings. Thread the shaft nuts onto the shafts finger tight.
11. 11

    Position control arm shafts
    Align the control arm shaft positions to match the alignment marks made during disassembly. Adjust the nuts so the same number of threads are exposed as noted earlier. This will get the alignment close to the previous setting.
12. 12

    Connect ball joint to spindle
    Raise the upper ball joint stud into the hole in the top of the steering knuckle. You may need to use a pry bar to align the holes or adjust the floor jack height slightly. Install the castle nut on the ball joint stud and tighten until snug. Ensure the taper seats properly in the knuckle.
13. 13

    Torque ball joint and control arm fasteners
    Torque the upper ball joint castle nut to manufacturer specifications (typically 50-70 ft-lbs for AMC applications). Continue tightening if necessary to align the castellations with the cotter pin hole. Install a new cotter pin and bend the ends to secure. Torque both control arm shaft nuts to manufacturer specifications (typically 65-80 ft-lbs for AMC applications) while the vehicle weight is on the suspension.
14. 14

    Remove jack and reinstall wheel
    Carefully lower and remove the floor jack from under the lower control arm. Install the wheel and tire assembly and thread the lug nuts by hand. Lower the vehicle to the ground and torque the lug nuts to specification (typically 75-85 ft-lbs) in a star pattern.

Reassembly

1. Torque all fasteners to manufacturer specifications using a calibrated torque wrench
2. Always install a new cotter pin in the ball joint castle nut - never reuse old cotter pins
3. Ensure all shims and spacers are reinstalled in their original positions to maintain approximate alignment settings
4. Final torquing of control arm shaft nuts should be performed with the vehicle at normal ride height to prevent bushing bind

Verification

• Verify the upper ball joint stud is fully seated in the steering knuckle taper with no movement
• Confirm the cotter pin is properly installed and bent to prevent backing out
• Check that all control arm mounting hardware is tight and properly torqued
• Bounce the front suspension and listen for any unusual noises or loose components
• Have the front end alignment checked and adjusted by a qualified technician as soon as possible after completion
• Test drive the vehicle at low speed and verify normal steering response and no pulling or vibration

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