Once you own an odd-ball, building a CJ or a Wrangler seems like cheating. Everybody in the world makes everything in the world for them. Just pick your modification, order it up, and bolt it on when the delivery guy drops it off. But what if nobody makes what you want? Or, what if you're the type who insists on building everything yourself, even if there's a bolt-on alternative.
Technically we fall into both categories, but in this particular case, there was no viable way to easily get what we were after with our '73 Commando project. With a busted-up front suspension, we took stock of what we had on hand to make it mobile. Luckily for us, what we had on hand was a bunch of really nice slightly-used Rancho suspension parts and some modified M.O.R.E. spring hangers from our '48 Willys pickup project. But we could've made junkyard stuff work in a pinch for even less money.
Here's our starting point....
Here's our starting point. The deeply offset stock Commando spring packs aren't close to any other Jeep spring in measurement. Ours had been given a monkey-cluster lift by tossing an incredibly thick add-a-leaf into the mix. Inverted shackles had severely bent the main springs, rendering them useless. The only saving grace to this disaster is the stainless extended brake lines had already been installed for us. Otherwise, we cut everything of the old suspension off and started with bare framerails.
We knew we wanted to swap the shackle location to the rear for a smoother ride and more predictable handling. We could have made our own spring hangers out of 3/16- or 1/4-inch steel (and that's very nearly what we did do), but the Mountain Off Road Enterprises (M.O.R.E.) YJ shackle reversal spring hanger brackets we severely modified for use on our Willys pickup were just sitting there calling to us. The cut hangers lower our ride height and move the hangers up and away from trail obstacles, but the company offers its spring hangers in a "Stubby" version that are 1 3/4-inch shorter than its standard spring hangers. Had they been available back when we ordered the ones we modified, the Stubbies are the ones we would have gone with.
Our springs are a pair of Rancho RS44044 Wagoneer 2 1/2-inch-lift packs, which are popular with the Jeep crowd for several reasons. They have a relatively short free-arch so they can be used as a spring-over without being goofy-tall, or spring-under application. Their 300-in/lb spring rate is a good match for a moderately-heavy Jeep running a V-8 and a winch, providing a smooth ride with good weight holding capacity. They have a 47-inch flat spring length with an offset centerpin location (22 1/2-inch and 24 1/2-inch) so they can be used to eke an extra bit of wheelbase. Finally, they're 2 1/2 inches wide with big 1 1/2-inch eyelets front and rear and they're tough as nails. We went spring-under because we prize a low center of gravity and we hate dealing with axle wrap. Plus, the spring-under works with our current steering linkages for a dirt-simple suspension upgrade.
We built our front suspension in a couple of afternoons, with most of the time spent cutting off the stock spring brackets. The first day we demoed the stock stuff and hung the new Rancho suspension, while the second day entailed welding on the shock mounts, modifying our driveshaft, and installing the bumpstops and shocks. In all, we're stoked with our custom suspension. It floats super smooth on the bumps at high speed, delivers plenty of droop and uptravel in the rocks, and is sure-footed and predictable on the street. For now we're running 33-inch tires, but we plan on installing some 38s on this rig in the not-too-distant future without changing the ride height.
Thankfully for us Commando...
Thankfully for us Commando frames are nearly fully-boxed, which saved us some cutting and plating work. We just had to build these small plates in front of the crossmember since this is where our spring hangers would mount with our home-built shackle reversal setup. We cut some cold-rolled, 1/8-inch-thick plate to size and welded it in.
We wanted to smooth the ride...
We wanted to smooth the ride on-road and ease hard hits at speed off-road, so a shackle reversal setup go the nod. We tacked the hangers into position and hung the Rancho RS44044 2 1/2 inch wide Wagoneer springs with the short centerpin to eye side facing forward. Normally you need to ensure the spring hangers are square and parallel with lots of measuring and some all thread bolted between both hangers eyelets bolt holes, but we cheated and used the old stock shackle hangers as a guide. Once our new spring hangers were tacked on, we removed the rivets holding on the stock shackle hangers and pounded them off.
Here's a closer look at our...
Here's a closer look at our spring hangers. We had modified a couple M.O.R.E. shackle reversal spring hangers for use in the rear of our '48 Willy pickup by cutting and shortening them. M.O.R.E. now offers its hangers in a "stubby" version which would have saved us some effort. Between the new spring mount location and the different centerpin-to-spring eye measurements the front axle was moved forward 2 inches. We could have moved it farther forward but modifications to the stock steering linkage and steering box mount would have been necessary.
We wanted to keep the suspension...
We wanted to keep the suspension low and simple. Rather than weld a shackle hanger on the bottom of the framerail, we used a 1 3/4-inch holesaw to pierce the boxed frame into which a 2 3/4-inch-long section of 1 3/4-inch, 0.120-wall tubing was welded. Standard 1 1/2-inch-diameter poly bushings can then be inserted. To determine the where to drill, we hung a single shackle on the spring and swung it up into place near the frame until the shackle was hanging around 45 degrees forward at full droop.
Mocking up our shackle hanger...
Mocking up our shackle hanger location at a forward-facing 45-degree angle with no load on the suspension (to mimic suspension droop) translated into a nice 20-30-degree shackle angle with the vehicle weight on the springs. This still allows the shackle plenty of rearward movement as the springs grow without hitting the framerails. More highly-arched springs will require longer shackles or a more-neutral shackle angle with the vehicle weight on the springs.
Since the stock spring packs...
Since the stock spring packs were narrower than the 2 1/2-inch-wide Rancho Wagoneer lift springs, we had to nip a bit off the centersection casting for spring U-bolt clearance. We used a pair of YJ spring plates with some stock Dana 30 U-bolts to cinch the axle to the springs. Don't forget to measure your caster and pinion angles. Our caster came out at a perfect 6.5 degrees, but you can use steel shims that bolt to the spring centerpins to dial in your angles. Shoot for 5-7 degrees of positive caster in the front axle for good handling on-road.
Because it's fairly easy to...
Because it's fairly easy to get 8 to10 inches of wheel travel out of Rancho's RS44044 springs, we needed to install some longer shocks. Back in the early 2000s we scooped up several pairs of these '99-'04 Super Duty shock mounts from the dumpsters of our local off-road shops. They're not as common nowadays, but if you can't find any at scrap-pricing the dealerships still sell them for around $20 each under PN F81Z-18183-A. Or, the older pre-'99 stamped steel F-250/F-350 mounts sell for even less under PN E5TZ-18183-A.
Finally, we rummaged through...
Finally, we rummaged through our parts shed and came up with a pair of 8-inch-travel Rancho RS5000 shocks (PN RS5156) off the front of an old '89 F-250 tow rig we used to own. They proved the right length, with plenty of uptravel without bottoming and lots of droop. We welded the lower shock mounts directly to the axle tube for clearance and to work with the shocks we had on hand.
With a shackle-forward arrangement,...
With a shackle-forward arrangement, the axle travels down and back as suspension droops and up and forward as it compresses, requiring comparatively little driveshaft slip spline travel. This is opposite of a shackle-reversal suspension, which sees more travel in the driveshaft slip spline. We lengthened our stock shaft for our increased wheelbase just enough that the slip splines wouldn't separate at full-droop. However, this didn't leave enough spline to fully collapse the shaft on suspension compression, so we used 1-inch Rancho dropped bumpstops (PN RS8203) to prevent the shaft from bottoming and destroying our T-case. It's only temporary until we can have a proper long-travel shaft built.