Coil Spring - Rear

This procedure covers the removal and replacement of rear coil springs on a 1972 Ford F-100 with 302ci V8, including safe suspension disassembly and spring compression techniques.

Warnings

Tools required

Parts

• Rear coil spring (driver side) × 1 — Use OEM specification or heavy-duty replacement
• Rear coil spring (passenger side) × 1 — Use OEM specification or heavy-duty replacement
• Shock absorber lower mounting hardware (if corroded) × 2 — Use OEM specification

Preparation

1. Park vehicle on level, solid ground with parking brake engaged and transmission in Park (automatic) or 1st gear (manual)
2. Place wheel chocks in front of both front wheels
3. Loosen (but do not remove) rear wheel lug nuts while vehicle is on ground
4. Apply penetrating oil to all rear suspension fasteners and allow to soak for 15-30 minutes minimum
5. Raise rear of vehicle using floor jack positioned under rear axle housing at differential center section
6. Place jack stands under frame rails just forward of rear axle, ensuring stands are on solid frame mounting points
7. Lower vehicle weight onto jack stands while keeping floor jack in place under axle housing with slight upward pressure
8. Remove rear wheels completely and set aside
9. Inspect coil spring compressor tool to ensure it is in good working condition with no damaged threads or bent components

Procedure

1. 1

   Support and position rear axle
   With vehicle securely on jack stands and floor jack supporting axle housing at differential, verify that the axle is level and jack is centered. The jack must remain under the axle throughout the entire procedure to control axle movement. Ensure at least 6 inches of clearance exists between frame and axle to allow coil spring removal.
2. 2

   Disconnect lower shock absorber mounts
   Locate the lower shock absorber mounting bolts on both sides of the axle housing. Using a box end wrench to hold the nut and a socket on the bolt head, remove both lower shock mounting bolts completely. Allow shocks to hang freely from upper mounts. Inspect the lower shock mount configuration on your vehicle and note how the lower shock attaches (bolt orientation and bracket type) before removal so it can be reassembled correctly.
3. 3

   Disconnect rear sway bar links (if equipped)
   If your F-100 is equipped with a rear sway bar (not standard on all 1972 models), disconnect both sway bar end links from the axle housing mounting points. Remove the nuts and bolts securing the links and allow the sway bar to hang freely. If no sway bar is present, proceed to next step.
4. 4

   Lower axle to release spring tension
   Very slowly and carefully lower the floor jack to allow the rear axle to drop downward. Lower only until the coil spring becomes loose between its upper seat (on frame) and lower seat (on axle housing). Stop immediately when spring tension is released but spring is still captive between seats. The axle should drop approximately 4-6 inches. Do not lower so far that brake hoses or emergency brake cables become strained.
5. 5

   Install coil spring compressor on first spring
   Working on one side only (driver or passenger), install the coil spring compressor tool per manufacturer instructions. The compressor hooks or plates must engage at least 3 full coils at both top and bottom of the spring. Ensure compressor components are centered on the spring and threads are properly engaged. Alternate tightening the compressor nuts or bolts evenly to compress the spring gradually. Compress until spring is fully compressed and no longer contacts either the upper frame mount or lower axle seat.
6. 6

   Remove compressed coil spring
   With spring fully compressed and tension relieved, carefully rotate and maneuver the spring assembly (with compressor still attached) out from between the frame and axle. The spring and compressor will come out as a single unit. Determine the clearest removal path for your specific suspension and maneuver the compressed spring assembly out accordingly. Place the compressed spring assembly in a safe location away from the work area.
7. 7

   Inspect spring seats and isolators
   Inspect the upper spring seat on the frame and lower spring seat on the axle housing. Look for rubber or urethane spring isolator pads that sit between the spring and metal seats. These pads often deteriorate and should be replaced if cracked, torn, or missing. Clean both spring seats with a wire brush to remove rust and debris. The 1972 F-100 typically uses rubber isolator pads at both upper and lower spring seats.
8. 8

   Install compressor on new spring
   Transfer the coil spring compressor from the old spring to the new replacement spring. Ensure the compressor is properly positioned with engagement on at least 3 coils at top and bottom. Compress the new spring evenly until it is approximately the same compressed length as the old spring was when removed. The spring must be compressed enough to fit freely between the upper frame seat and lower axle seat with no contact.
9. 9

   Position and install new spring
   Position the compressed new spring between the frame upper seat and axle lower seat. Ensure any spring isolator pads are properly positioned. The spring end tang (pigtail end of spring coil) must align with the positioning slot or hole in both the upper and lower spring seats. Note the end-tang orientation of the original spring before removal and install the new spring with tangs oriented identically to match the positioning slots in the seats.
10. 10

    Raise axle to seat spring
    With spring positioned correctly and still compressed, slowly raise the floor jack to lift the axle upward. Continue raising until the lower spring seat on the axle makes firm contact with the bottom coil of the spring. Verify the spring end tang is properly located in its positioning slot before proceeding.
11. 11

    Release spring compressor gradually
    With axle raised and supporting the spring, very slowly and evenly loosen the spring compressor tool. Alternate loosening the compressor fasteners to release tension gradually and evenly. Monitor that the spring remains properly seated with end tangs in their positioning slots as tension is released. Continue until spring compressor is completely loose and all spring tension is transferred to the upper and lower seats. Remove the compressor tool completely.
12. 12

    Repeat for opposite side spring
    Repeat steps 5 through 11 for the spring on the opposite side of the vehicle. It is critical that both springs are replaced as a matched pair to maintain proper vehicle ride height and handling. Never replace only one rear spring.
13. 13

    Reconnect shock absorbers
    Raise the axle with the floor jack to its normal ride height position (approximately level with frame or slightly above). Reconnect the lower shock absorber mounting bolts on both sides. Install bolts from the direction specified by original configuration and tighten snugly. Torque to the factory specification for your vehicle. If the factory value is unavailable, use a value appropriate to the actual bolt size and grade and verify against a service manual before final tightening. Factory torque specification for lower shock absorber mounting bolt on 1972 Ford F-100 rear suspension is 52.0 lb-ft (70.0 Nm).
14. 14

    Reconnect sway bar links (if equipped)
    If a rear sway bar is installed, reconnect both sway bar end links to the axle housing mounting points. Install all fasteners and tighten securely. Ensure sway bar moves freely without binding.
15. 15

    Final inspection and reinstall wheels
    Perform a complete visual inspection of all work performed. Verify both coil springs are properly seated with end tangs in position slots. Confirm all fasteners are tight and no tools or parts have been left in the suspension area. Reinstall both rear wheels, threading lug nuts by hand initially. Lower vehicle from jack stands using floor jack to control descent. Once vehicle weight is on wheels, torque all lug nuts to 100 ft-lbs in a star pattern. Remove jack stands and lower jack completely.

Reassembly

1. Replace wheel lug nuts in a star pattern and torque to 100 ft-lbs after vehicle is on the ground
2. Test drive vehicle at low speed in a safe area to verify proper suspension operation and listen for any unusual noises
3. Have front end alignment checked after spring replacement, as rear spring changes can affect overall vehicle ride height and geometry

Verification

• Measure vehicle ride height at both rear wheel wells from ground to fender lip; measurements should be equal side-to-side within 1/2 inch
• Bounce rear of vehicle several times and verify it settles back to normal height without sagging or unusual noises
• Verify both rear shock absorbers are functioning by checking for resistance during bounce test
• Test drive vehicle on smooth and rough road surfaces to confirm normal ride quality without bottoming out or unusual sounds
• Visually inspect that vehicle sits level from side to side when viewed from rear
• Re-torque all suspension fasteners after 50-100 miles of driving

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