This procedure covers the replacement of the idler arm on a 2015-2020 Ford F-150 with 3.5L EcoBoost engine, which connects the steering linkage to the frame and allows for steering movement.

Warnings

Tools required

Parts

• Idler arm assembly × 1 — Use OEM specification or quality aftermarket equivalent
• Castle nut cotter pin (if applicable) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Place wheel chocks behind rear wheels
3. Loosen passenger side front wheel lug nuts while vehicle is on ground (do not remove)
4. Raise front of vehicle with floor jack and secure on jack stands at frame contact points
5. Remove passenger side front wheel completely
6. Spray all fasteners to be removed with penetrating oil and allow 10-15 minutes to soak
7. Visually inspect steering linkage for additional wear or damage

Procedure

1. 1

   Access the idler arm
   From underneath the passenger side front of the vehicle, locate the idler arm. It connects the center link (drag link) to the frame rail. Clean the area around all connection points with a wire brush to expose fastener heads and remove rust or debris.
2. 2

   Support the center link
   Place a jack or support under the center link near the idler arm connection point to prevent the steering linkage from dropping when the idler arm is disconnected. This prevents stress on other steering components and makes reassembly easier.
   ℹ️Supporting the linkage prevents damage to the pitman arm connection and maintains alignment reference.
3. 3

   Disconnect idler arm from center link
   Remove the castle nut or tie rod nut connecting the idler arm stud to the center link. If a castle nut is used, remove and discard the cotter pin first. Use a pickle fork, ball joint separator, or ball joint press to separate the idler arm stud from the center link taper. Insert the tool between the center link and idler arm, then tighten or strike according to tool type until the taper releases.
   ⚠Pickle forks will damage the dust boot. Only use if replacing the idler arm. A ball joint press is preferred for preservation.
   Torque spec

   Tie Rod Castle Nut55 Nm (41 lb-ft)
4. 4

   Remove idler arm frame mounting bolts
   Locate the bolts securing the idler arm bracket to the frame rail on the passenger side. These are typically two or three bolts depending on the specific idler arm design. Use the appropriate socket and wrench to remove these bolts completely. Support the idler arm as you remove the final bolt to prevent it from falling.
   Torque spec

   Idler Arm Bolts75 Nm (55 lb-ft)
5. 5

   Remove old idler arm
   Once all fasteners are removed, carefully extract the idler arm assembly from the vehicle. Note the orientation and position of any shims, washers, or spacers that may be present between the idler arm bracket and frame. Keep these for reinstallation unless new hardware is provided with the replacement part.
6. 6

   Prepare mounting surface
   Clean the frame mounting surface thoroughly with a wire brush to remove rust, old thread locker, and debris. Inspect the frame mounting area for cracks, damage, or excessive rust. Clean the threads of the mounting bolts if reusing, or prepare new bolts if supplied with the replacement idler arm.
7. 7

   Install new idler arm to frame
   Position the new idler arm assembly to the frame rail, ensuring proper orientation matches the original installation. Install any shims or spacers in their original positions. Thread the mounting bolts by hand to prevent cross-threading, then snug them finger-tight. Do not fully torque at this stage.
8. 8

   Connect idler arm to center link
   Lower the center link slightly if needed to align the idler arm stud with the center link taper hole. Insert the idler arm stud into the center link taper. Install the new castle nut or tie rod nut onto the stud and tighten to draw the taper connection tight.
9. 9

   Torque center link connection
   Using a torque wrench, tighten the castle nut or tie rod nut to specification. If using a castle nut, tighten to the specified torque, then advance only as needed to align the cotter pin hole (do not back off to align). Install a new cotter pin and bend the ends to secure.
   ⚠Never loosen a castle nut to align the cotter pin hole. Only tighten further to the next alignment slot.
   Torque spec

   Tie Rod Castle Nut55 Nm (41 lb-ft)
10. 10

    Torque frame mounting bolts
    With the idler arm now connected to the center link, torque the frame mounting bolts to specification in a cross pattern (if multiple bolts). This ensures even clamping force and proper alignment of the idler arm bracket to the frame.
    Torque spec

    Idler Arm Bolts75 Nm (55 lb-ft)
11. 11

    Remove support and check movement
    Remove the support from under the center link. Manually move the steering linkage through its range of motion to verify the idler arm pivots freely without binding. Check that all connections are secure and no fasteners were missed.
12. 12

    Reinstall wheel
    Place the passenger front wheel back onto the hub, threading lug nuts by hand. Tighten lug nuts in a star pattern snug but not to final torque while vehicle is still raised.
13. 13

    Lower vehicle and final torque
    Carefully lower the vehicle from jack stands to the ground. With the vehicle weight on the wheels, torque the lug nuts to specification in a star pattern to ensure even wheel seating.
    Torque spec

    Wheel Lug Nuts156 Nm (115 lb-ft)

Reassembly

1. All fasteners have been installed and torqued during the procedure steps
2. Ensure no tools or parts were left in the wheel well or under the vehicle
3. Verify the cotter pin is properly installed and secured if applicable

Verification

• Start the engine and turn the steering wheel slowly from lock to lock while stationary, listening for any unusual noises from the idler arm area
• Visually inspect the idler arm connections for any movement or looseness while an assistant turns the steering wheel
• Test drive the vehicle at low speed in a safe area, checking for proper steering response and any pulling or vibration
• After test drive, re-inspect all fasteners for tightness and check for any fluid leaks (though this vehicle uses electric steering)
• Schedule a professional wheel alignment as steering component replacement affects toe settings and tire wear

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