This procedure covers the removal and replacement of the front radius arm (lower control arm) on a 2011-2014 Ford F-150 3.5L EcoBoost 4WD, including ball joint separation and proper torque sequencing.

Warnings

Tools required

Parts

• Radius arm (lower control arm) × 1 — Use OEM specification
• Ball joint castellated nut × 1 — Recommended replacement
• Cotter pin for ball joint × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage 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 and support on jack stands at frame rails
5. Remove front wheel on side being serviced
6. Spray all radius arm bolts and ball joint nut with penetrating oil, allow 10-15 minutes to soak

Procedure

1. 1

   Support the knuckle assembly
   Position a floor jack under the front spindle/knuckle to support the weight of the suspension. Raise jack just enough to lightly compress the coil spring. This relieves tension on the radius arm and prevents the knuckle from dropping when the ball joint is separated.
2. 2

   Remove ball joint cotter pin and nut
   Straighten and remove the cotter pin from the ball joint stud. Using a 21mm socket, remove the castellated nut from the ball joint stud at the spindle. Note the orientation of the nut for reassembly.
3. 3

   Separate ball joint from knuckle
   Using a ball joint separator tool or pickle fork, separate the ball joint stud from the steering knuckle. Position the separator between the radius arm and knuckle, applying pressure to the ball joint stud. Strike the separator with a hammer or use a threaded separator to force the taper loose. Do not damage the ball joint boot if reusing the radius arm.
   ⚠The knuckle may drop suddenly when the ball joint releases. Ensure the floor jack is properly supporting the assembly.
4. 4

   Remove front radius arm mounting bolt
   Locate the front radius arm-to-crossmember bolt. This is the forward mounting point of the radius arm. Using an 18mm socket and wrench, remove the nut and bolt. The bolt passes through the front bushing of the radius arm. You may need to use a pry bar to relieve binding pressure on the bolt.
5. 5

   Remove rear radius arm mounting bolt
   Locate the rear radius arm-to-crossmember bolt. This is the rearward mounting point of the radius arm. Using an 18mm socket and wrench, remove the nut and bolt. The bolt passes through the rear bushing of the radius arm. Support the radius arm as you remove this final bolt.
6. 6

   Remove radius arm from vehicle
   With both mounting bolts and the ball joint separated, carefully remove the radius arm from the vehicle. Maneuver it around the steering linkage and brake components. Inspect the old radius arm for wear, damage, or the reason for replacement.
7. 7

   Prepare new radius arm for installation
   Clean the mounting surfaces on the crossmember with a wire brush. Compare the new radius arm to the old unit to ensure correct part. Check that the ball joint boot is intact and properly seated. Apply a light coat of anti-seize to the bolt threads.
8. 8

   Install new radius arm
   Position the new radius arm into the vehicle, aligning the front and rear bushings with the crossmember mounting points. Insert both front and rear mounting bolts through the bushings and crossmember, but do not tighten at this time. Hand-thread the nuts onto the bolts to hold the radius arm in position.
9. 9

   Connect ball joint to knuckle
   Using the floor jack, raise the knuckle assembly to align the ball joint stud with the hole in the steering knuckle. Insert the ball joint stud through the knuckle. Install the new castellated nut onto the ball joint stud and tighten to specification. The nut slots must align with the cotter pin hole in the stud.
   ℹ️If the cotter pin hole does not align with a castellated slot, tighten the nut further until alignment is achieved. Never loosen the nut to align the cotter pin hole.
   Torque spec

   Ball Joint Nut101 Nm (75 lb-ft)
10. 10

    Install cotter pin
    Insert a new cotter pin through the ball joint stud and castellated nut. Bend the ends of the cotter pin around the nut to secure it in place. Ensure the cotter pin is fully seated and cannot back out.
11. 11

    Install wheel and lower vehicle
    Reinstall the front wheel and hand-thread all lug nuts. Lower the vehicle until the tire just touches the ground but the suspension is not yet fully loaded. Torque the wheel lug nuts in a star pattern to specification. Then fully lower the vehicle so the suspension is supporting the vehicle weight.
    Torque spec

    Wheel Lug Nuts156 Nm (115 lb-ft)
12. 12

    Final torque radius arm mounting bolts
    With the vehicle weight fully on the suspension, torque the front and rear radius arm mounting bolts to specification. This must be done with the suspension at normal ride height to prevent premature bushing wear. Torque both the front and rear bolts.
    ⚠Torquing the radius arm bolts with the suspension unloaded will cause premature bushing failure and require replacement.
    Torque spec

    Control Arm Bolts165 Nm (122 lb-ft)

Reassembly

1. Verify all fasteners are torqued to specification
2. Remove floor jack from under vehicle
3. Lower vehicle completely and remove jack stands

Verification

• Test drive the vehicle at low speed and verify no unusual noises from the front suspension
• Check that steering responds normally with no binding or unusual feel
• Inspect the ball joint area for any fluid leaks or looseness
• Schedule a front-end alignment as radius arm replacement will affect camber, caster, and toe settings

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