Replace the rear leaf spring U-bolt kit, which secures the rear axle to the leaf springs. This procedure involves safely supporting the vehicle and removing/installing the U-bolts and associated hardware.

Warnings

Tools required

Parts

• Leaf spring U-bolt kit (includes U-bolts, nuts, washers, and saddle plate) × 1 — Use OEM Ford specification or quality aftermarket
• U-bolt saddle plate (if not included in kit) × 1 — Often included with U-bolt kit

Preparation

1. Park vehicle on level, solid ground and engage parking brake
2. Chock the front wheels securely on both sides
3. If U-bolts are visibly rusted, spray with penetrating oil and allow 15-30 minutes to soak
4. Loosen wheel lug nuts while vehicle is on ground (do not remove)
5. Raise rear of vehicle with floor jack at rear axle differential housing
6. Install jack stands under frame rails at manufacturer-specified jacking points
7. Remove rear wheels and set aside
8. Position floor jack under rear axle housing to support axle weight (do not lift, just support)

Procedure

1. 1

   Identify U-bolt locations
   Locate the U-bolts on the side requiring replacement. Each side has two U-bolts that wrap around the axle housing and pass through the leaf spring and saddle plate. Inspect for corrosion, damage, or elongation of the U-bolt threads.
2. 2

   Remove U-bolt nuts
   Using an 18mm socket, remove all four nuts from the U-bolts on the side being serviced. Start by loosening each nut 2-3 turns in a crisscross pattern to prevent binding, then remove completely. If nuts are seized, apply additional penetrating oil and use a breaker bar or impact wrench.
3. 3

   Remove U-bolts and saddle plate
   Remove both U-bolts from the leaf spring. The U-bolts should slide out downward once nuts are removed. Remove the saddle plate (top plate between U-bolts and spring). The axle housing is now only supported by the floor jack and leaf spring - do not disturb the jack position.
   ⚠️Ensure floor jack is securely supporting axle weight before removing U-bolts completely. The axle can shift if not properly supported.
4. 4

   Clean mounting surfaces
   Use a wire brush to thoroughly clean the top surface of the axle housing, the bottom surface of the leaf spring, and both sides of the saddle plate contact areas. Remove all rust, corrosion, and old debris to ensure proper seating of new components.
5. 5

   Inspect leaf spring and axle alignment
   With U-bolts removed, verify the leaf spring center bolt is tight and properly locating the axle. Check that the axle housing sits centered on the spring with the spring center pin engaged in the axle housing locating hole. Adjust jack height if needed to align properly.
6. 6

   Position new saddle plate
   Place the new saddle plate on top of the leaf spring, centered over the axle housing. The plate should have holes aligned for the U-bolt threads. Apply a light coat of anti-seize to the saddle plate contact surfaces if desired.
7. 7

   Install new U-bolts
   Insert the new U-bolts from below, threading them up through the leaf spring and saddle plate holes. Ensure U-bolts are seated fully around the axle housing with equal thread exposure on both sides. Start all four nuts by hand to ensure proper thread engagement.
8. 8

   Tighten U-bolt nuts in sequence
   Tighten U-bolt nuts in a crisscross pattern using multiple passes. First pass: snug all four nuts finger-tight plus 1/4 turn. Second pass: tighten to 50 lb-ft. Third pass: tighten to 75 lb-ft. Final pass: tighten to manufacturer specification of 76-98 lb-ft (check service manual for exact spec as torque specs provided do not include U-bolt specification).
   ℹ️U-bolt nuts must be tightened gradually in multiple passes to ensure even clamping force and prevent spring or plate distortion.
9. 9

   Verify axle position
   After torquing U-bolts, verify the axle housing is still properly centered on the leaf spring and the vehicle ride height appears normal. The saddle plate should be flush against the spring with no gaps.
10. 10

    Repeat for opposite side
    If replacing U-bolts on both sides, repeat steps 1-9 for the opposite side of the vehicle. Maintain axle support with the floor jack throughout the process.
11. 11

    Reinstall wheels
    Reinstall rear wheels, threading lug nuts by hand initially. Tighten lug nuts in a star pattern to specification.
    Torque spec

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

    Lower vehicle and final torque check
    Raise vehicle slightly to remove jack stands, then lower vehicle completely to the ground. With full vehicle weight on suspension, perform a final torque check on all U-bolt nuts to confirm proper torque. This is critical as the suspension settling can affect torque values.

Reassembly

1. Ensure all U-bolt nuts are torqued to specification with vehicle weight on suspension
2. Verify no tools or parts are left under vehicle
3. Check that wheels are properly torqued after vehicle has been driven 50-100 miles

Verification

• Test drive vehicle at low speed and verify no unusual noises, vibrations, or handling issues from rear suspension
• After 50-100 miles of driving, re-torque U-bolt nuts as they may settle slightly under load
• Visually inspect U-bolts for proper seating and verify no gaps between saddle plate and leaf spring
• Check rear axle alignment and ensure vehicle tracks straight with no pull to either side

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