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Spring-Over Suspension Conversion

Front Passenger Side
Christian Lee | Writer
Posted December 16, 2003

Bigger Tires and more flexfor YJs

You've seen them on the trail: Jeep YJs with 35-inch tires flexing through extreme obstacles with ease. Or better yet, another YJ sitting on 33s completing the same obstacle without a worry. How is this possible when you can't get your rig through without dragging U-bolts across boulders or stuffing tires in fenders? It's called a spring-over-axle setup, friends, and it's just about the greatest means of increasing suspension flex and tire clearance in leaf-spring suspension systems.

Considering the benefits of a spring-over-axle suspension setup, it's not surprising that one of the most frequently asked questions we hear is: How do I go spring-over? A good deal of kits are available from the aftermarket, but there's no reason why one couldn't put together his or her own kit with off-the-shelf and used parts. Depending on the desired tire size, the stock springs may be reused and still supply a few inches of lift simply by residing atop the axle. Having the stock springs as an option also allows the owner the opportunity to lift their vehicle in stages, going bigger as needed, or as money permits. Since we were determined to run 36-inch tires, however, we chose to use a set of 2.5-inch lift springs from Deaver Spring. Along with the springs, we acquired other necessary equipment, including Rancho RS9000 shocks, limiting straps, extended bumpstops from T&J Performance, extended brake lines, new spring perches, and U-bolts. Once the new suspension was installed, we measured for new driveshafts using a CV 'shaft in the rear. We recommend a slip-yoke eliminator if one isn't already installed.

Addressing our steering needs, we decided to maintain use of the stock steering knuckle, which now situated the tie rod beneath the springs. Using a dropped pitman arm and an S-Link drag link from T&J, we nearly achieved the factory steering geometry, even with the absence of a track bar. Other steering options when completing a spring-over conversion include crossover style and high-steer designs, but since our tie rod was even with the centerline of the axle, it was far enough out of harm's way that it wouldn't create any clearance issues.

With parts in hand, we headed to T&J Performance in Orange, California, where we completed the spring-over conversion. Check out the photos for an overview of the process.

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  • Converting your suspension to a spring-over-axle configuration will offer greater flexibility and increased ground clearance for the fitment of taller tires.

  • 1. Using parts from T&J Performance Center, we converted this '94 Jeep YJ to a spring-over-axle setup. The suspension now clears 36-inch tires and offers excellent axle articulation.

  • 2. The stock spring-under suspension setup limits off-road capability and tire size. By moving the leaf spring on top of the axle, ground clearance increases dramatically.

  • 3&4. We elected to use a set of custom 2.5-inch leaf packs from Deaver Spring, which were constructed with a reverse military eye.

  • 5. New spring perches are used in completing the spring-over conversion, as it's necessary to remove the stock perches welded in place under the axle.

  • 6. T&J Performance offers these bumpstop extensions that can be cut to the determined size and welded in place.

  • 7. We maintained use of the stock YJ steering knuckle, which will situate the tie rod beneath the springs. To do so requires use of a modified drag link, such as T&J's S-Link.

  • 8. After the shocks were pulled, the front and rear stock springs were removed and set aside. We continued the disassembly up front, removing the stock drag link, antisway bar, track bar, and brake lines.

  • 9. New spring perches were welded in place on top of the axle tube. To achieve the proper pinion angles, we loosely installed the springs and U-bolts on the new perches before tacking them in place. We then removed the springs and U-bolts before welding.

  • 10. The new springs and U-bolts were then installed on the perches and torqued in place.

  • 11. New shackles were used in the front and rear.

  • 12. With the springs resting atop the axles, the new, longer shocks were installed, along with limiting straps and longer brake lines.

  • 13. The S-Link drag link from T&J replaces the factory drag link and is said to greatly steering response and handling.

  • 14. The new bumpstop was cut to the proper length and welded to the frame.

  • 15. A new dropped pitman arm was installed to help maintain the factory steering geometry.

  • 16. T&J built this custom anti-axle-wrap system that mounts between the rear axlehousing and the frame.

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