4" is the standard trail-build lift for an early Bronco. It clears 35" tires with the right backspacing, gives a real articulation gain over a 2" kit, and stays in a height range where quality twin-tube or monotube shocks still work without remote reservoirs. Budget $800 for a DIY spring-and-shock install and closer to $2,200 once caster correction, extended brake lines, steering geometry, and an alignment are included. Those supporting items are what separate a safe 4" lift from a twitchy one, and skipping them is the reason so many lifted early Broncos feel nervous above 50 mph.
A 4" suspension lift is the baseline for a capable early Bronco trail build, sitting between the mild 2" lift and a full spring-over-axle conversion. It buys 35" tire clearance, better approach and departure angles, real articulation, and driveline angles that remain manageable with stock-length shafts. Because the early Bronco is leaf-sprung at both ends with no track bars or control arms, a lift here is a spring swap rather than a geometry rebuild — which is what keeps the job inside a home garage.
Confirm wheel fitment against the backspacing guide before ordering. The wrong offset either rubs the radius of the fender at full stuff or pushes the tire out far enough to load the closed-knuckle Dana 44's wheel bearings harder than the design intends.
Not all 4" kits are the same spring. The difference between a pleasant truck and a buckboard is leaf count and pack design, not the advertised height.
Whatever you pick, buy the kit with greasable shackles and a full polyurethane or rubber bushing set included. Reusing 50-year-old shackle bushings on new springs wastes the new springs.
This is the section owners skip and then spend a year regretting.
Caster. Arching a leaf spring rotates the axle, and 4" of lift pulls roughly 2 degrees of caster out of the front end. Low caster reads as vague on-center feel, slow return-to-center, and a truck that wanders in a crosswind. Correct it with tapered degree shims between the spring and the perch — $30 for a pair — or by cutting and rotating the perches on a rebuilt front end. Target 4-6 degrees positive at ride height and verify with an angle gauge on the knuckle face, not by feel.
Steering geometry. The early Bronco's box-and-bellcrank steering puts the drag link at an angle that changes with lift. At 4" the drag link and the front spring travel through different arcs, and the resulting bump steer shows as the truck darting when one front tire hits a bump. A drop pitman arm ($120-180) is the cheap correction; a crossover or high-steer conversion is the thorough one. Pair either with the steering box brace and stabilizer, because a lifted early Bronco puts real load into a frame-mounted box that was never braced from the factory.
Shackle geometry. If the truck is road-driven and still feels nervous after caster correction, a front shackle reversal is the next step. It changes the axle's fore-aft arc and generally improves both ride and steering stability.
At 4", front and rear driveshaft angles increase but stay inside U-joint operating range with stock suspension travel, so a slip yoke eliminator is not mandated by the lift alone. Reconsider once you add a locker, chase aggressive articulation, or go taller — at that point read the driveshaft upgrade guide and the SYE and CV driveshaft guide. Inspect front U-joints annually regardless; the steeper operating angle wears them faster than stock.
Gearing is the other half of the 35" decision. Stock 3.50 or 4.11 gears with 35s make the truck dull off idle and hard on the clutch or the C4. Plan a re-gear to 4.56 or 4.88 into the same budget rather than treating it as a later surprise, and recalibrate the speedometer to match.
| Item | Typical cost |
|---|---|
| 4" complete spring kit (value tier) | $900-1,100 |
| 4" complete spring kit (Wild Horses / Duff) | $1,000-1,300 |
| Shocks, set of four | $320-560 |
| Extended stainless brake lines | $110 |
| Caster shims | $30 |
| Drop pitman arm | $120-180 |
| Bumpstop extensions | $60 |
| Alignment | $100-150 |
| DIY total | $1,700-2,200 |
The $800 low end assumes springs and shocks only on a truck whose steering and brake lines are already sorted. Plan on $2,000 for a complete, safe 4" build, and treat the re-gear as a separate line item that follows within the same season.
| Part | Vendor | Est. price |
|---|---|---|
| Wild Horses / James Duff 4" complete leaf spring kit, early Bronco | Wild Horses 4x4 / James Duff | ~$1100 |
| Skyjacker 4" early Bronco spring kit (budget tier) | Skyjacker | ~$950 |
| Bilstein 5100 series shocks (set of 4) | Bilstein | ~$380 |
| Stainless braided extended brake lines (front pair + rear) | Various | ~$110 |
| Caster correction shims, 2-4 degree tapered pair | Various | ~$30 |
| Greasable shackles and polyurethane bushing set | Various | ~$90 |
| Drop pitman arm or crossover steering kit | James Duff / WH4x4 | ~$180 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.
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