This procedure replaces the rear strut assembly on a 2015-2020 Ford F-150 with 3.5L EcoBoost V6 engine, including removal of the strut-to-knuckle connection and upper strut mount.

Warnings

Tools required

Parts

• Rear strut assembly (complete, pre-assembled) × 1 — Use OEM Ford specification or equivalent

Preparation

1. Park vehicle on level, solid surface and engage parking brake
2. Chock front wheels securely
3. Loosen rear wheel lug nuts 1/4 turn while vehicle is on ground (do not remove)
4. Raise rear of vehicle with floor jack at rear differential or frame rail
5. Support vehicle securely on jack stands placed under frame rails behind rear axle
6. Remove rear wheel completely
7. Apply penetrating oil to strut-to-knuckle bolts and allow to soak for 10-15 minutes if fasteners show corrosion

Procedure

1. 1

   Access upper strut mount
   Open rear door or tailgate to access interior. Fold down or remove rear seat cushion if necessary to access the cargo area. Locate the upper strut tower access panel on the interior side panel in the cargo area behind the rear wheel well. Some models may have a small plastic cover that pops out; remove this cover to expose the three upper strut mount nuts.
2. 2

   Support rear knuckle assembly
   Position floor jack under the rear knuckle/hub assembly and raise slightly to take the load off the strut. The jack should support the weight but not lift the vehicle. This prevents the knuckle from dropping when the strut is disconnected. Ensure the jack is stable and won't slip during strut removal.
   ⚠The knuckle assembly will drop suddenly if not supported. Keep hands clear and ensure jack is positioned securely.
3. 3

   Disconnect sway bar link (if obstructing access)
   If the sway bar link interferes with strut removal on your specific model, disconnect it from the lower control arm or strut bracket. Use an Allen key to hold the ball stud shaft while removing the nut with a socket. Note the orientation for reassembly.
   Torque spec

   Sway Bar Link70 Nm (52 lb-ft)
4. 4

   Remove upper strut mount nuts
   From inside the vehicle cargo area, use a 15mm socket to remove the three nuts securing the upper strut mount to the strut tower. Do NOT remove the center nut on top of the strut shaft - this holds the spring assembly together. Support the strut from below as you remove the final nut.
   ⚠️DO NOT loosen or remove the center strut shaft nut. This nut retains the compressed spring and removal will cause violent spring release resulting in serious injury.
5. 5

   Remove strut-to-knuckle bolts
   Locate the two bolts connecting the strut to the rear knuckle. These are typically 18mm bolts running horizontally through the strut bracket and knuckle. Remove both bolts completely. Use a breaker bar if needed - these bolts are torqued to 140 Nm and may be tight. You may need to use a pry bar to separate the strut bracket from the knuckle once bolts are removed.
   Torque spec

   Strut-to-Knuckle Bolts140 Nm (104 lb-ft)
6. 6

   Remove strut assembly
   With upper nuts and lower bolts removed, carefully guide the strut assembly down and out from the wheel well. The upper mount should slide down through the strut tower opening. Maneuver the strut around brake lines and any other components. Lower the jack supporting the knuckle slightly if needed for clearance.
7. 7

   Inspect and clean mounting surfaces
   Inspect the strut tower mounting surface and knuckle bracket for damage, rust, or deformation. Wire brush both the strut tower surface and knuckle mounting holes to remove rust and debris. Check the knuckle bolt holes for elongation or cracking. Inspect brake lines and ABS sensor wiring for damage. Replace any damaged components before installing new strut.
8. 8

   Install new strut assembly
   Guide the new complete strut assembly up through the wheel well, aligning the upper mount studs with the three holes in the strut tower. Push the upper mount fully into position. Thread on the three upper strut mount nuts hand-tight from inside the vehicle. Do not fully torque at this time.
9. 9

   Connect strut to knuckle
   Raise the floor jack to lift the knuckle assembly up to the strut bracket. Align the holes in the knuckle with the strut bracket. Insert both strut-to-knuckle bolts and thread nuts hand-tight. You may need to use a pry bar to align holes precisely. Ensure bolts are fully seated before tightening.
10. 10

    Torque strut-to-knuckle bolts
    Using a torque wrench, torque both strut-to-knuckle bolts to 140 Nm (104 lb-ft) in a cross pattern. Verify both bolts are properly seated and achieve the specified torque. These bolts are critical for suspension geometry and safety.
    Torque spec

    Strut-to-Knuckle Bolts140 Nm (104 lb-ft)
11. 11

    Torque upper strut mount nuts
    From inside the vehicle, torque the three upper strut mount nuts to 50 Nm (37 lb-ft) in a star pattern to ensure even loading of the mount. These nuts secure the strut to the chassis.
    Torque spec

    Strut Tower Nuts50 Nm (37 lb-ft)
12. 12

    Reconnect sway bar link (if disconnected)
    If the sway bar link was disconnected in step 3, reconnect it now. Insert the ball stud into the mounting point, thread on the nut, hold the shaft with an Allen key, and torque the nut to 55 Nm (41 lb-ft).
    Torque spec

    Sway Bar Link70 Nm (52 lb-ft)
13. 13

    Reinstall wheel and lower vehicle
    Remove the floor jack from under the knuckle. Reinstall the rear wheel, threading lug nuts by hand initially. Snug lug nuts in a star pattern with a wrench but do not torque yet. Remove jack stands and carefully lower the vehicle to the ground.
14. 14

    Final torque wheel lug nuts
    With vehicle weight on the ground, torque all wheel lug nuts to 156 Nm (115 lb-ft) in a star pattern using a torque wrench. This ensures proper wheel seating and prevents lug nut loosening.
    Torque spec

    Wheel Lug Nuts156 Nm (115 lb-ft)

Reassembly

1. Reinstall any interior trim panels or seat cushions that were removed to access the upper strut mount
2. Verify all fasteners are torqued to specification
3. Remove wheel chocks

Verification

• Test drive vehicle at low speed in a safe area and verify no unusual noises from rear suspension
• Check for proper handling and verify vehicle does not pull to one side
• Inspect all fasteners for proper torque after test drive
• Have vehicle alignment checked by a professional within 100 miles - suspension replacement affects wheel alignment
• Re-torque wheel lug nuts after 50-100 miles of driving

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