Idler Arm

This procedure covers removal and replacement of the idler arm on a 1970 AMC Rebel Machine, restoring proper steering geometry and eliminating play in the steering linkage.

Warnings

Tools required

Parts

• Idler arm assembly × 1 — Use OEM specification or quality replacement for 1970 AMC Rebel
• Idler arm castle nut × 1 — Reusable if not damaged
• 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 right front wheel lug nuts while vehicle is on ground
4. Apply penetrating oil to idler arm mounting bolts and castle nut, allow to soak 15-20 minutes
5. Raise front of vehicle with floor jack at front crossmember
6. Support vehicle securely on jack stands placed under frame rails behind front suspension
7. Remove right front wheel completely

Procedure

1. 1

   Access the idler arm
   Locate the idler arm on the passenger side frame rail. It connects the center link (drag link) to the frame. Clean the area around the castle nut at the center link connection and the two mounting bolts at the frame bracket using a wire brush.
2. 2

   Remove cotter pin from castle nut
   Straighten the cotter pin at the castle nut on the idler arm stud where it connects to the center link. Use pliers to pull the cotter pin completely out and discard it. Do not reuse old cotter pins.
3. 3

   Loosen castle nut
   Using a 21mm socket or large adjustable wrench, loosen and remove the castle nut from the idler arm stud at the center link connection. Keep the nut as it may be reusable if threads are in good condition.
4. 4

   Separate idler arm from center link
   Position the pickle fork or tie rod separator between the center link and the idler arm taper. Strike the pickle fork with a hammer to drive it into the taper joint, breaking the connection. Support the center link with your other hand to prevent it from dropping suddenly. If using a ball joint press, position and tighten to push the stud out of the center link.
5. 5

   Remove idler arm frame mounting bolts
   Locate the two bolts securing the idler arm bracket to the passenger side frame rail. Using a 19mm socket and ratchet, remove both mounting bolts completely. Support the idler arm assembly as you remove the second bolt to prevent it from falling.
6. 6

   Remove idler arm assembly
   Pull the idler arm assembly away from the frame rail and maneuver it out from under the vehicle. Inspect the mounting surface on the frame rail for damage, rust, or deformation. Clean mounting surface with wire brush if needed.
7. 7

   Prepare new idler arm
   Compare the new idler arm to the old unit to verify correct replacement part. Check that the stud taper is clean and free of grease. Verify that the mounting holes align with the frame bracket. If the new idler arm includes pre-installed grease fittings, ensure they are tight.
8. 8

   Install new idler arm to frame
   Position the new idler arm assembly against the frame rail, aligning the mounting holes. Insert both mounting bolts through the idler arm bracket and into the frame rail. Thread bolts by hand initially to ensure proper alignment, then tighten in a cross pattern. Torque mounting bolts to 35-40 ft-lbs or until snug and secure since torque specifications are not available in database.
9. 9

   Connect idler arm to center link
   Lift the center link and align it with the idler arm stud. Push the stud taper up through the hole in the center link until fully seated. Thread the castle nut onto the stud by hand, ensuring it threads smoothly without cross-threading.
10. 10

    Torque castle nut and install cotter pin
    Tighten the castle nut to approximately 35-40 ft-lbs or until snug and the ball joint taper is fully seated. Continue tightening until the next castle slot aligns with the hole in the stud. Never loosen to align. Insert a new cotter pin through the castle nut and stud hole, then bend the ends of the cotter pin around the nut to secure it.
11. 11

    Lubricate idler arm
    If the idler arm has a grease fitting, use a grease gun to pump chassis grease into the fitting until fresh grease appears at the seal. Wipe away excess grease. Apply 3-4 pumps of grease or until slight resistance is felt.

Reassembly

1. Reinstall right front wheel and thread lug nuts by hand
2. Lower vehicle until tire just touches ground, then torque lug nuts to 75 ft-lbs in a star pattern
3. Lower vehicle completely and remove jack stands
4. Remove wheel chocks
5. Test steering for smooth operation and proper return to center before driving

Verification

• Check that all mounting bolts are tight and secure with no movement in idler arm bracket
• Verify castle nut is properly torqued and cotter pin is correctly installed and bent
• Grasp the idler arm and attempt to move it by hand - there should be no vertical play in the ball joint
• Turn steering wheel lock-to-lock while stationary and verify smooth movement with no binding or unusual noises
• Test drive vehicle at low speed in a safe area and verify steering responds normally with no wandering
• Schedule a professional wheel alignment immediately as steering geometry has been affected

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