Trailing Arm Bushing

Replace worn trailing arm bushings on the rear suspension to restore proper axle alignment and ride quality.

Warnings

Tools required

Parts

• Trailing arm bushing (front position) × 2 — Use OEM specification or heavy-duty aftermarket
• Trailing arm bushing (rear position) × 2 — Use OEM specification or heavy-duty aftermarket
• Anti-seize compound × 1 — Standard copper or nickel-based

Preparation

1. Park vehicle on level, solid ground and engage parking brake.
2. Place wheel chocks in front of both front wheels.
3. Loosen rear wheel lug nuts while vehicle is still on ground.
4. Raise rear of vehicle using floor jack at rear axle center section.
5. Place jack stands under frame rails behind cab, ensuring vehicle is stable.
6. Remove both rear wheels completely.
7. Spray all trailing arm bushing bolts and nuts with penetrating oil and allow to soak for 15-30 minutes.

Procedure

1. 1

   Support the rear axle
   Position a hydraulic bottle jack or transmission jack under the center of the rear axle differential housing. Raise jack just enough to make contact and support the axle weight, but do not lift the axle. The axle must remain free to move slightly during bushing removal.
2. 2

   Remove shock absorber lower mounting
   Locate the lower shock absorber mounting bolt on the driver side axle housing bracket. Remove the nut and bolt securing the shock to the axle bracket. Allow the shock to hang freely or secure it out of the way with wire or bungee cord. Repeat for passenger side.
3. 3

   Remove front trailing arm bushing bolt (driver side)
   Locate the front leaf spring eye bushing mounting point where the leaf spring front eye connects to the frame hanger bracket. This is a large bolt that passes through the bushing and frame bracket. Using a wrench to hold the nut, remove the bolt using a breaker bar and socket. The bolt is typically 5/8" or 3/4" diameter. Tap bolt out with a hammer if necessary.
4. 4

   Remove rear trailing arm bushing bolt (driver side)
   Locate the rear leaf spring shackle assembly where the spring rear eye connects to the frame bracket through the shackle. This assembly has bushings at both the shackle-to-frame and shackle-to-spring eye connections. Remove the bolt and nut in the same manner as the front bushing. With both bolts removed, the trailing arm is now free from the frame.
5. 5

   Remove trailing arm from axle housing
   The leaf spring is secured to the axle housing with 2 U-bolts. Remove the 4 nuts securing the U-bolts to the spring plate. Once the U-bolts are removed, the axle can be separated from the spring. You may need to use a pry bar to break any corrosion bond. Set the trailing arm on a workbench for bushing removal.
6. 6

   Press out old bushings
   Using a ball joint press or appropriate bushing press tool with correctly sized receiving cups, press the old rubber bushings out of the trailing arm eyes. The front eye bushing and rear shackle bushings are different sizes. The shackle assembly has bushings at both the frame mount and spring eye mount. Press from the inside of the bushing outward, using a cup smaller than the bushing outer diameter to push on the inner sleeve, and a receiving cup larger than the bushing to catch it as it exits. If bushings are severely deteriorated, they may come out in pieces.
7. 7

   Clean trailing arm bushing bores
   Thoroughly clean the bushing bores in the trailing arm eyes using a wire brush and solvent. Remove all rust, old rubber residue, and debris. The bores must be clean and smooth for new bushings to seat properly. Inspect for cracks or damage to the trailing arm itself.
8. 8

   Install new bushings
   Apply a light coat of dish soap or rubber lubricant (NOT petroleum-based grease) to the outer diameter of the new bushings to aid installation. Using the bushing press with appropriately sized cups, press the new bushings into the trailing arm eyes. Ensure bushings are pressed in straight and are fully seated flush with or slightly below the surface of the trailing arm eye. The bushing orientation should match the original with any flats or voids positioned correctly.
9. 9

   Reinstall trailing arm to axle housing
   Position the leaf spring back onto the axle housing spring pad. Install the 2 U-bolts over the axle housing and through the spring plate. Install the 4 nuts and tighten in a cross pattern to ensure even clamping. Tighten to 88.0 lb-ft (120.0 Nm).
10. 10

    Reinstall front trailing arm bushing bolt
    Apply anti-seize compound to the front eye bushing mounting bolt threads. Insert the bolt through the frame hanger bracket and leaf spring front eye bushing. Install the nut finger-tight only at this stage. Do not fully tighten yet.
11. 11

    Reinstall rear trailing arm bushing bolt
    Apply anti-seize compound to the shackle mounting bolt threads. Install the shackle to the frame bracket with one bolt and to the spring rear eye with another bolt, with bushings installed at both connection points. Install the nut finger-tight only. Do not fully tighten yet.
12. 12

    Repeat process for passenger side
    Complete steps 3 through 11 for the passenger side leaf spring, removing old bushings, installing new bushings, and reinstalling the spring with bolts finger-tight.
13. 13

    Load suspension to ride height
    Using the hydraulic jack under the rear axle, carefully raise the axle assembly until the suspension is at approximately normal ride height position. This simulates the vehicle sitting on the ground. The suspension must be loaded before torquing bushing bolts to prevent binding and premature bushing failure.
14. 14

    Torque all trailing arm bushing bolts
    With the suspension loaded to ride height, torque all leaf spring mounting bolts (front eye bolts and shackle bolts, both sides) to the manufacturer specification. 88.0 lb-ft (120.0 Nm) Verified detail (Torque specification for trailing arm bushing mounting bolts (frame bracket) on 1972 Ford F-100): 88.0 lb-ft (120.0 Nm)
15. 15

    Reinstall shock absorbers and wheels
    Reconnect the lower shock absorber mounting bolts on both sides and torque to manufacturer specification (verify for your specific application). Lower the axle jack slightly and reinstall both rear wheels. Tighten lug nuts in a star pattern. Lower vehicle to ground and torque lug nuts to 100 ft-lbs. Verified detail (Torque specification for rear shock absorber lower mounting bolt on 1972 Ford F-100): 52.0 lb-ft (70.0 Nm)

Reassembly

1. Always torque trailing arm bushing bolts with the suspension at ride height, never with the axle hanging free.
2. Double-check that all four trailing arm-to-axle housing bolts are tight on both sides.
3. Verify shock absorbers are securely mounted at lower positions.
4. Test drive vehicle slowly at first to verify proper installation and listen for any unusual noises.

Verification

• Perform a visual inspection of all bolts and hardware to confirm proper installation.
• Test drive vehicle on smooth road and check for improved ride quality and reduced clunking noises.
• Inspect bushings after 100 miles of driving for any signs of abnormal wear or movement.
• Consider having rear axle alignment checked by a professional, especially if vehicle shows signs of rear axle misalignment such as abnormal tire wear or dog-tracking.

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