Installing Axles and Suspension
In our June issue, we covered the OK4WD buildup of front and rear Rockcrusher 60R axle assemblies that were destined for use in a '75 Jeep CJ-5. In this issue, we'll detail the suspension portion of the buildup as completed by Tri-County Gear in Pomona, California. The Rockcrusher 60R diffs are heavy-duty assemblies that dwarf the factory-installed Dana 30 front and AMC 20 rear axles in the CJ. With such a stout axle package, we weren't satisfied with maintaining the factory spring-under setup, which significantly impedes ground clearance. A spring-over axle configuration was our goal, and we also intended to install a shackle-reversal system to improve the ride quality both on and off the trail.
The spring-over axle was a no-brainer, and we likely could have stuck with just that, but since we were installing YJ springs (which are longer and wider and require mods to the spring mounts anyway), we decided to take a few extra steps and install the shackle reversal as well. After researching our options, we called Alan Ball from Mountain Off-Road Enterprises (M.O.R.E.). Alan helped us narrow down what parts we'd need to complete the installation using one of M.O.R.E.'s shackle-reversal kits, which are actually designed for use on '76-and-later CJs rather than the Narrow Track '75 we were attempting to convert. A few extra modifications were in order, but the crew at Tri-County Gear performed these tasks quite easily. M.O.R.E.'s shackle-reversal kit features new, fully welded pivot brackets that are ready to bolt into existing bolt holes in the frame, along with 3/8-inch-thick spacer plates to accommodate variations in winch mounting, new greasable shackles, polyurethane bushings, and additional custom spring shackle mounting components. M.O.R.E. offers CJ shackle-reversal kits to accommodate either CJ leaf springs or the wider YJ leaf springs. As previously stated, we'll be using YJ leaf springs in this conversion in hopes of creating increased flex and stability.
To achieve some degree of lift beyond what is afforded through the spring-over axle (SOA) suspension configuration, we elected to use 1-1/2-inch-lift, reverse-military-eye Black Diamond leaf springs; however, once the springs were in place, we realized that with the weight of the engine the 1-1/2 inches of lift might not be enough. Luckily enough, we had a set of heavy-duty, 2-inch-lift Wrangler leaf packs from Alcan Spring left over from a previous project. The springs were a perfect fit in the front of the CJ and provided just the right amount of lift to level the vehicle and clear the 37x12.50R15 Parnelli Jones Dirt Grip tires on 15x10 Eaton beadlocks.
With the added spring flex and height, we knew that we'd also want longer-travel shocks to reap the rewards of this setup. M.O.R.E. came through once again with its long-travel shock mount cage that's offered for '72-'86 Jeep CJs. It's a bolt-in affair on '82-and-later frames and requires minor modifications to fit the earlier models. The kit is shipped bare steel and includes left and right shock towers and an engine crossbrace designed to fit beneath the grille supports that extend from the firewall. The kit will not fit AMC V-8s with the factory smog pump below the power steering pump, but it will fit CJs with Chevy V-8 conversions and I-6-equipped CJs with minor modifications to the air intake hose. The new towers will support Superlift shocks.
To top off the construction of the Big-Build CJ-5, we acquired a set of 37-inch Parnelli Jones Dirt Grip tires and 15x10, 32-bolt Eaton beadlocks, both from National Tire & Wheel. The tire and wheel package arrived at Tri-County Gear mounted and balanced and ready to be bolted up to the new axles. Check out the photos and captions for the rest of the details of this installation.