With all apologies to Forrest Gump, life is not like a box of chocolates; it’s more like a bouncy house. As you grow up, you get all full of yourself and hot air, and then growing older is like having a slow leak; you just kind of slowly collapse. An older Jeep’s suspension—even with an aftermarket lift kit—can slowly collapse in the same fashion as a leaking bouncy house if it’s used regularly for rock crawling and on more technical trails. And it occurs so gradually you don’t even realize the Jeep’s getting lower and its ride is deteriorating.
A quarter century ago, I installed a Skyjacker 4-inch lift kit on my ’82 CJ-7 Renegade, although I used YJ front leaf springs because of their additional width and stability to provide additional clearance for 35-inch-diameter tires (in fact, Skyjacker offers 6-inch YJ lift kits but maxes out the CJ kits at four inches). Things were a lot different in those days—the Internet was just being developed, there was no e-mail, cell phones were the size of bricks, and a Jeep’s air conditioning meant going lidless and dropping the windshield. Since the original lift kit install, this particular Jeep has covered trails all over the Southwest (Arizona, Colorado, New Mexico, Utah, and Southern California), including several trips to the Hammers, Moab, Farmington, the Rubicon, and most points in between.
Although I do tow my ’82 on a trailer, it’s no “trailer queen.” It can’t be flat-towed with a Terraflex 4:1 low range, and its 35-inch Goodyear MT/R tires are way more expensive than trailer tires, and its 4.56 differential gear ratio twists the Chevy 350ci V-8 too high for long-distance freeway travel. This Jeep sees an average of two trails each month here in northwestern Arizona. In other words, it gets a lot of work. Therefore, after 25 years of rockcrawling on the more technical trails in the Southwest, this Jeep’s suspension was getting a bit saggy (it was about an inch lower than when the original kit was new), side hills were causing excessive leaning, the shocks were getting somewhat soft, and a front spring had bent. It was time for replacement.
After finding out that my driving style bent one of the standard-wrap front leaf springs, I opted for Skyjacker’s military-wrap springs. These springs’ secondary leaves are longer and wrap around the bushing at each end, while the main spring also adds an outside roll to each end, which makes the springs much, much stronger and much less likely to bend or straighten under severe stress.
While choosing the military wrap, I also had to decide whether a 6-inch lift or a 4-inch lift—both available from Skyjacker for YJ models—would be a better fit for my driving style. The 6-inch would be more impressive looking and give better clearance. But it would also create more difficulty climbing in and out of the Jeep. It could also cause problems with the driveline components because of the more severe driveshaft angles. I decided the 4-inch lift kit with boomerang shackles from Summit Racing would be more than adequate for my needs, and the longer, stronger boomerang shackles also added an inch to the lift kit’s height. In fact, the combination raised the Jeep 21⁄2 inches.
Although the 25-year-old Skyjacker suspension doesn’t look saggy, it had lost more than an inch of lift in its quarter-century of rockcrawling, mud bogging, sand bowling, and just plain exploring. Safely support the vehicle with jack stands before starting to remove parts. Age and stream crossings—not to mention mud bogs—cause nuts and bolts to become very difficult to remove.
You may need a floor jack to raise and lower the differential to match the springs’ arc when removing the old springs or installing the new ones. Skyjacker’s installation instructions are excellent, so we won’t be using space to copy them here, just a few tips so save you some time.
With the exception of the spring, all these components come in the boomerang shackle kit (M.O.R.E. Boomerang Shackles, PN LS9081), called that because of their shape.
These YJ front spring hangers were installed 25 years ago and are no longer available. However, Summit Racing offers M.O.R.E. YJ spring hangers (PN SR103) if you’re looking to change your CJ springs.
Fortunately, on a CJ, the rear pivoting spring hangers can be spread to accommodate the wider YJ front springs (the rear springs are the same width). We used a 12-inch crescent wrench to bend the wings outward.
When attaching the shackles to the spring eyelets, be sure the zerks are accessible and are not facing the wrong way (the rear springs’ zerks must face away from the fuel tank so they can be greased).
The point of the bend is mounted toward the Jeep, not away, on all four springs.
Each of the eight U-bolts may have to be widened to fit your axles. Use a vice and length of pipe for the modifications.
Don’t widen the U-bolts too much—they have to fit over the axle housings and through the holes in the spring plates. The largest U-bolt goes over the differential housing on the short side.
On a CJ-7, the rear springs just clear the fuel tank, so make sure the zerks are faced outward and the shackle is in the proper position as well.
Skyjacker’s Nitro shock absorbers are nitrogen-filled, which keeps the fluid cool even during rapid cycling. The shocks also come with dust boots for the shafts.
Use white lithium grease on the neoprene bushings before inserting them. Sometimes all it takes to insert the bushings is some muscle.
If the fit is too tight or the bushings are unusually stiff, you may need the added strength of a vice to insert the bushings.
The new shocks are very similar to the 25-year-old shocks from Skyjacker.
There are two advantages of YJ springs over CJ springs: There is more front-end stability due to their width, and all four springs are the same width and length, so only one spring is needed for an emergency trail repair.
On many installations, it takes two people to align the axle-centering pin in the spring.
We had to negotiate the AMC 20’s truss with the new U-bolts. The truss and Warn’s full-floating axles have kept this AMC 20 alive for a quarter-century.
Leave the wire in place on the Nitro shocks until you’re ready to install them in the lower shock mounts. Cut the wire and guide the shock into place.
Each spring plate is equipped with a skid plate protecting the U-bolt ends, so the U-bolts must be shortened to allow the skid plate mounting. U-bolt skid plates are highly recommended, otherwise the rocks and boulders will damage the U-bolts.
New Goodyear MT/R with Kevlar 35x12.50R15 tires and Mickey Thompson Classic Baja Lock black wheels complete the installation.
