A YJ leaf pack lasts 100,000 miles if you're lucky, less if it's lived in the rust belt. Sagging springs, broken main leaves, and snapped center pins all warrant replacement. Plan on a full day for both axles, half a day for one. Torque the u-bolts to 90 ft-lbs; everything else gets torqued with the wheels on the ground.
The YJ runs leaf springs front and rear — five-leaf packs that double as both spring and axle locator. When they sag, ride height drops, caster angle drifts out of spec, and steering goes vague. When the center pin snaps, the axle walks rearward on the spring and your driveshaft angles change in a hurry. Bushings dry out and squeak. If your YJ has 150,000 miles or has lived through more than two desert summers, the springs are probably tired.
Stock-height replacements from Old Man Emu (OME) or BDS will give you back factory ride height with fresh bushings and a controlled rate. If you've been planning a 2.5-inch or 4-inch lift, do the springs and the lift in the same job — replacing leaves twice in a year is wasted work. Rough Country, Skyjacker, and BDS all make YJ-specific kits. Avoid mystery aftermarket "lift springs" from auction sites; the steel quality and arch consistency between pairs is unpredictable.
The factory torque spec is **u-bolts: 90 ft-lbs, shackle bolts: 95 ft-lbs, main eye bolts: 105 ft-lbs, crossmember bolts: 30 ft-lbs**. Some installers torque u-bolts to 70–80 ft-lbs out of fear of bending the spring plates — the factory plates are stamped steel and the 90 ft-lbs spec assumes them. Heavier aftermarket plates handle the full 90 ft-lbs with no complaint. **U-bolts can be torqued at any time. Shackle bolts and main eye bolts must be torqued with the full weight of the vehicle on the ground**, or the bushing seats compress to one position and bind through suspension travel.
The hardest part of the job is breaking loose 30-year-old shackle bolts. Soak every bolt with PB Blaster the night before, then heat with a torch if needed. Cutting the bolts and replacing with greaseable hardware is often faster than fighting them out intact. Greaseable bolts also make future bushing service trivial. Plan for a $40 hardware budget on top of the spring cost.
| Part | Vendor | Est. price |
|---|---|---|
| Old Man Emu stock-height YJ front leaf pack | ARB/OME | ~$280 |
| Rough Country 2.5" lift YJ leaf pack (front pair) | Rough Country | ~$200 |
| U-bolt kit (front pair, fits stock-height YJ) | Daystar/Skyjacker | ~$45 |
| Greaseable bolt and bushing kit | Currie/Daystar | ~$65 |
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.