This procedure covers the removal and replacement of the radius arm (lower control arm) on the 2021-2024 Ford F-150 3.5L EcoBoost RWD, including ball joint separation and proper torque sequence.

Warnings

Tools required

Parts

• Radius arm (lower control arm) × 1 — Use OEM specification
• Ball joint cotter pin × 1 — Use OEM specification
• Anti-seize compound × 1 — Generic

Preparation

1. Park vehicle on level surface and engage parking brake
2. Chock rear wheels securely
3. Spray all fasteners with penetrating oil and allow to soak for 15-30 minutes
4. Loosen wheel lug nuts while vehicle is on ground (do not remove)

Procedure

1. 1

   Raise and support vehicle
   Raise the front of the vehicle using a floor jack at the frame rail. Place jack stands under the frame on both sides for stability. Remove the wheel and tire assembly completely. Ensure the suspension is hanging freely.
2. 2

   Disconnect sway bar link
   Locate the sway bar link connection at the lower control arm. Use an Allen key to hold the shaft while loosening the sway bar link nut with a wrench. Remove the nut completely and disconnect the sway bar link from the control arm. Allow the link to hang from the sway bar.
   Torque spec

   Sway Bar Link71 Nm (52 lb-ft)
3. 3

   Remove ball joint cotter pin
   Locate the ball joint castle nut at the steering knuckle connection. Straighten and remove the cotter pin using pliers or side cutters. Discard the old cotter pin as a new one will be installed during reassembly.
4. 4

   Loosen ball joint nut
   Loosen the ball joint castle nut but do not remove it completely. Leave it threaded on by 2-3 turns to protect the threads and prevent the knuckle from dropping suddenly when the taper is broken.
   ⚠Do not completely remove the nut before breaking the taper joint, as the knuckle may drop suddenly.
5. 5

   Separate ball joint from knuckle
   Position a ball joint separator tool between the control arm and steering knuckle. Apply force to break the taper joint. Once the taper is broken and the ball joint stud is free, remove the castle nut completely. Lower the steering knuckle away from the control arm.
   ⚠Ball joint may release suddenly. Keep hands clear and support the knuckle as needed.
6. 6

   Remove front radius arm bolt
   Locate the front mounting bolt that secures the radius arm to the frame crossmember. This is typically the forward-most connection point. Use a breaker bar and socket to remove the bolt and any washers. Note the orientation of any bushings or hardware for reassembly.
7. 7

   Remove rear radius arm bolt
   Locate the rear mounting bolt securing the radius arm to the frame bracket. Support the control arm with your hand or a jack to prevent it from dropping. Remove the bolt completely. Carefully lower and remove the radius arm from the vehicle.
8. 8

   Inspect and clean mounting points
   Inspect the frame mounting points for damage, excessive wear, or corrosion. Clean all mounting surfaces with a wire brush. Check that the ball joint seat on the steering knuckle is clean and undamaged. Apply anti-seize compound to the bolt threads.
9. 9

   Install new radius arm
   Position the new radius arm into place. Insert the rear mounting bolt first, threading it hand-tight only. Then install the front mounting bolt hand-tight. Do NOT torque these bolts yet - they must be torqued with vehicle weight on the suspension.
   ⚠Control arm mounting bolts must remain loose until vehicle weight is on suspension to prevent bushing damage.
10. 10

    Connect ball joint to knuckle
    Raise the steering knuckle and align the ball joint stud with the hole in the knuckle. Insert the stud fully into the knuckle taper. Install the castle nut and tighten to specification. Install a new cotter pin through the castle nut slot and ball joint stud, then bend the ends to secure.
    Torque spec

    Ball Joint Nut101 Nm (75 lb-ft)
11. 11

    Reconnect sway bar link
    Align the sway bar link with the mounting point on the control arm. Install the nut while holding the shaft with an Allen key. Torque the nut to specification while preventing the shaft from rotating.
    Torque spec

    Sway Bar Link71 Nm (52 lb-ft)
12. 12

    Install wheel and lower vehicle
    Install the wheel and tire assembly. Thread all lug nuts by hand, then snug them in a star pattern. Carefully lower the vehicle until the tires contact the ground but the full weight is not yet on the suspension. Remove jack stands and lower the vehicle completely so all weight is on the wheels.
13. 13

    Torque control arm bolts with weight on suspension
    With the vehicle on the ground and full weight on the suspension, torque the front and rear control arm mounting bolts to specification. This ensures the bushings are in their neutral position and will not bind or wear prematurely.
    ⚠Vehicle must be at normal ride height with weight on suspension when torquing control arm bolts.
    Torque spec

    Control Arm Bolts165 Nm (122 lb-ft)
14. 14

    Torque wheel lug nuts
    Torque the wheel lug nuts to specification in a star pattern to ensure even pressure on the wheel hub. Double-check that all lug nuts are properly seated and torqued.
    Torque spec

    Wheel Lug Nuts156 Nm (115 lb-ft)

Reassembly

1. Verify all fasteners are tightened to proper torque specifications
2. Ensure the new cotter pin is properly installed and bent at the ball joint
3. Confirm the sway bar link is securely connected and the shaft is not spinning

Verification

• Test drive the vehicle at low speed and verify no unusual noises or vibrations from the front suspension
• Check for proper steering feel and that the vehicle tracks straight
• Perform a visual inspection under the vehicle to confirm no loose fasteners or parts
• Schedule a professional alignment as suspension geometry has been disturbed

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