This procedure covers the removal and replacement of the rear trailing arm on a 2011-2014 Ford F-150 3.5L EcoBoost 4WD, including disconnection from the frame and axle mounting points.

Warnings

Tools required

Parts

• Rear trailing arm assembly × 1 — Use OEM Ford specification for proper fitment
• Trailing arm to frame bolt and nut × 1 — Replace if corroded or damaged
• Trailing arm to axle bolt and nut × 1 — Replace if corroded or damaged

Preparation

1. Park vehicle on level, solid surface and engage parking brake
2. Place wheel chocks in front of front wheels
3. Loosen rear wheel lug nuts while vehicle is on ground, but do not remove
4. Raise rear of vehicle using floor jack at rear differential or frame rail
5. Support vehicle on jack stands positioned at manufacturer-recommended frame points
6. Remove rear wheel on side being serviced
7. Spray penetrating oil on trailing arm mounting bolts at frame and axle, allow to soak 15-20 minutes

Procedure

1. 1

   Support the rear axle
   Position a floor jack under the rear axle housing near the trailing arm mounting point. Raise jack until it just contacts the axle to provide support, but do not lift the vehicle. This prevents the axle from dropping when the trailing arm is disconnected.
2. 2

   Locate trailing arm mounting points
   Identify the trailing arm which runs longitudinally from the frame to the rear axle. The forward end attaches to the frame rail with a single bolt and bushing. The rear end attaches to a bracket on the axle housing with a single bolt. Note the orientation of any washers or spacers.
3. 3

   Remove frame mounting bolt
   Using an 18mm or 21mm socket (verify size on your vehicle), remove the nut from the trailing arm to frame bolt. Support the bolt head with a wrench while removing the nut. Once the nut is removed, drive the bolt out from the trailing arm using a punch or drift if necessary. Note the bolt orientation for reinstallation.
4. 4

   Remove axle mounting bolt
   Using an 18mm or 21mm socket, remove the nut from the trailing arm to axle housing bolt. Again, support the bolt head while removing the nut. Once free, drive the bolt out. The trailing arm may need to be pried away from the bracket slightly to clear the bolt.
5. 5

   Remove trailing arm from vehicle
   With both bolts removed, carefully lower and remove the trailing arm from the vehicle. Inspect the mounting points on both the frame and axle for damage, rust, or wear. If bushings remained in the frame or axle mounts, remove them and clean the bores thoroughly with a wire brush.
6. 6

   Prepare new trailing arm
   Compare the new trailing arm to the old unit to ensure proper match. Verify that bushings are properly installed in the new arm and are oriented correctly. Clean any preservation oil from mounting surfaces and hardware contact areas.
7. 7

   Install trailing arm to axle bracket
   Position the new trailing arm with the rear bushing aligned with the axle mounting bracket. Insert the axle mounting bolt from the correct direction (match original orientation). Start the nut on the bolt threads but do not tighten yet. The trailing arm should pivot freely on this bolt.
8. 8

   Install trailing arm to frame mount
   Swing the forward end of the trailing arm up to align with the frame rail mounting point. You may need to use the floor jack to raise or lower the axle slightly to achieve alignment. Insert the frame mounting bolt through the bushing and frame bracket. Start the nut on the bolt threads but do not tighten yet.
9. 9

   Verify alignment and clearances
   With both bolts installed finger-tight, verify that the trailing arm has proper clearance from the frame, driveshaft, exhaust, and brake lines throughout the suspension travel. Check that no wiring or brake lines are pinched or stressed.
10. 10

    Torque trailing arm fasteners with vehicle at ride height
    Lower the vehicle so the suspension is at normal ride height (wheels on ground or axle supported at ride height). Torque the trailing arm to frame bolt nut and trailing arm to axle bolt nut to 165.0 Nm (122.0 lb-ft). These fasteners must be torqued at ride height to prevent bushing pre-load and premature wear.
    Torque spec

    Control Arm Bolts165 Nm (122 lb-ft)
11. 11

    Reinstall wheel
    Mount the wheel back onto the hub, threading lug nuts by hand initially. Tighten lug nuts in a star pattern to seat the wheel, then torque to specification.
    Torque spec

    Wheel Lug Nuts156 Nm (115 lb-ft)

Reassembly

1. Ensure all tools and parts are removed from under the vehicle before lowering
2. Remove jack stands and lower vehicle completely to ground
3. Perform final torque verification of all fasteners with vehicle at curb weight
4. If replacing both trailing arms, repeat procedure on opposite side

Verification

• Test drive vehicle at low speed and verify no unusual noises from rear suspension
• Check for proper rear axle alignment and tracking
• Re-torque all trailing arm fasteners after 50-100 miles of driving
• Inspect for any fluid leaks or damage to nearby components
• Consider professional wheel alignment if vehicle pulls or tire wear is uneven

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