Leaf Spring Suspension Upgrade - Chevy Brand Pages - Chevy Brand Pages

Leaf-spring suspensions have been around forever, and there are tweaks you can do to make one spring work differently than another. You can taper the ends, use smaller leaves, use overloads, make bigger arches, relocate spring eyes, and so on. All of these things make leaf springs ride differently. But what about using longer leaves to absorb the vehicle's suspension force over a longer leverage arm? What is entailed in this sort of modification? Obviously, one spring hanger has to be moved. But what else? Remember that nothing is ever as easy as it sounds, and we definitely ran across that old clich again with this suspension build.

As far as custom suspensions go, this was a fairly simple project that you too could build at home with a welder. We used a '75 Blazer with a bolt-on 6-inch lift, a block-lifted rear, and some blown-out shocks as a test dummy and recipient of a new, much more supple suspension.

The plan was to make a slinky suspension that we could crawl and twist the K5 with, while still being able to jam down a stretch of dirt road or through the dunes at high speeds. We started the buildup with a set of 7-inch-longer Deaver front leaf packs, 14-inch-travel Bilstein 7100-series remote-reservoir shocks, Energy Suspension bumpstops, 11-pack rear leaves, and an Off-Road Design shackle flip. By the end of the project, we had also added new centerpins, a driveshaft, bronze shims, and Off-Road Design's 1-inch zero-rate add-a-leaf to the list. Follow along as we start the buildup and address any issues as they arise.

When we ordered the front leaf packs, we were unsure how to properly mount them, as the new springs place the shackle directly below the body mount. A quick call to Deaver led us to Baja Shop in Orange, California, to assist us in mounting the new front Deaver leaf packs. They had performed this long-spring conversion before, so were familiar with the shackle placement. Sure enough, Miguel Medina and Shawn Clark made a 1 3/4-inch hole for a bushing to mount the shackle directly under the body mount.
When we ordered the front leaf packs, we were unsure how to properly mount them, as the ne
Shawn Clark went to work making custom shackles that were 2 inches longer than the originals. He used 3/8-inch cold-rolled plate cut into 8-inch-long straps. The longer length will allow the leaf springs to flatten out to a longer length than a shorter shackle would, and will also allow more droop.
Shawn Clark went to work making custom shackles that were 2 inches longer than the origina
The Deaver long leaves measure out to 51 1/2 inches unweighted, while the old stock-length leaves measure out to 44 1/2 inches unweighted. The 7-inch-longer leaves will allow for more suspension travel and a smoother ride, as the force upon the spring is now distributed over a longer leverage arm (the longer leaf).
The Deaver long leaves measure out to 51 1/2 inches unweighted, while the old stock-length

The new shackle mount is 5 inches farther back than the original on the frame and mounts directly under the body mount. We placed an Energy Suspension bushing into the 1 3/4-inch hole and ran a 9/16-inch bolt through the shackle and bushing. Once together, we found that the front axle was moved forward about 1 1/2 inches. And though a longer wheelbase is usually a benefit, it might create some steering linkage and sway bar issues, depending on whatcha got under your rig. In our case, the crossover steering was not an issue, and we had no sway bar to deal with.
The new shackle mount is 5 inches farther back than the original on the frame and mounts d
With the front leaves mounted, we finished the rest of the suspension and fine tuning at Advance Automotive in Torrance, California. Jim Pierce started by using 1 3/4-inch, 0.120-wall tubing to make some front shock hoops to fit the 14-inch-stroke Bilsteins. The frame was plated where the hoops attach to better distribute the load over a larger surface area, and we used a connecting crossmember between the two hoops to help support the load.
With the front leaves mounted, we finished the rest of the suspension and fine tuning at A
Eric Swenston mocked up where the dual front 14-inch stroke Bilstein 7100-series shocks would go, and then bolted the shock spacers and mounts together before tack-welding them into place on the shock hoop. This gives us a chance to double-check and make sure everything lines up before making any final welds into place.
Eric Swenston mocked up where the dual front 14-inch stroke Bilstein 7100-series shocks wo

We also needed to mount the rear shocks, so Jim Pierce took it upon himself to make a new rollcage and incorporate the rear shock mounts into it.
We also needed to mount the rear shocks, so Jim Pierce took it upon himself to make a new
The old rollcage in this Blazer was made very poorly, and the hardtop did not even fit with it in. Pierce plated the frame with 3/16-inch steel where the cage's tubing attaches to the body.
The old rollcage in this Blazer was made very poorly, and the hardtop did not even fit wit
The lower mounts were welded on top of the spring plates and made to accept two shocks in case we wanted to add a second shock to each rear corner. For now we chose to go with just one shock per side in the rear in order to keep the back seat. But if we ever decide differently, all we would have to do is lose the rear seat and weld a couple of tabs onto the rear shock crossmember, and we would be good to go to a dual rear-shock setup. Every now and then we actually like to plan for possible future changes.
The lower mounts were welded on top of the spring plates and made to accept two shocks in

To complement the front, we used Off Road Design's shackle-flip kit to turn the tension shackle into a compression-shackle design. This gave us about a 4-inch lift in the rear, plus it angled the pinion for better rear driveline angle. We used a very soft 13-leaf spring pack that gave us another 2 inches of lift. The ORD shackle flip allowed us to run a much flatter spring, therefore allowing for better flex than a 4-inch-taller leaf spring would have.
To complement the front, we used Off Road Design's shackle-flip kit to turn the tension sh
We opted for these pyramid-type bumpstops from Energy Suspension. They allow 3-4 inches of inhibited cushioning before bottoming out on themselves. We're not sure that we like where we chose to place the bumpstops, but this was the easiest place to mount to for now, and if we find a problem with the setup, we'll change it later. That's what trial and error is all about.
We opted for these pyramid-type bumpstops from Energy Suspension. They allow 3-4 inches of
When we put the front leaves on, we had to make new shackles and also drill a new shackle-mount hole. The new shackle was 2 inches longer, plus the shackle-mount hole in the frame was about 2 inches lower than the original. When you think about it, it's obvious: The pinion was going to be rotated down, along with the knuckles. Not only did this give a bad driveline angle, but it also gave us scary caster issues. The front wheels were now trying to steer under the truck when we cranked the wheel. To address this problem, we went back to Deaver to get some 4-degree bronze shims. This rotated the axle back up and alleviated much of the pinion angle and caster problem.
When we put the front leaves on, we had to make new shackles and also drill a new shackle-

When we put the front end together, we knew we'd have around a 6-inch lift, to match the rear end. It turned out to be a little higher than that: around 7 inches. We also had a very soft spring pack in the rear, so it made the rear sag even more as the weight of the truck was biased toward the rear with the taller front end. We liked the super-soft ride of the rear, so we didn't want to add another leaf to the pack, but we didn't want to add a conventional block, no matter how short it was. Stephen Watson at Off Road Design again had the answer for our rear end with his 1-inch zero-rate add-a-leaves that include new centerpins and tie into the leaf pack. This was all it took to level the truck.
When we put the front end together, we knew we'd have around a 6-inch lift, to match the r
While we were back at Deaver grabbing some shims, we also got some new long centerpins. Our leaf packs were too thick for any of the supplied centerpins to be long enough to tie the zero-rate add-a-leaves and front shims into the leaf packs. When you pull your centerpins, your leaves will probably misalign themselves, forcing you to try to jimmy the centerpin through each leaf separately. When doing this, try using a punch to line up the holes, and a prybar to separate the leaves enough to allow you to see what you're doing.
While we were back at Deaver grabbing some shims, we also got some new long centerpins. Ou
The last issue we came across was the shackle hitting the body mount when fully drooped in the front. We can address this one of two ways: We could trim the front of the body mount to allow the shackle to flip more forward, or we could use limiting straps on the axle. We chose limiting straps since we did not really want the shackle swinging any more forward and possibly flipping the wrong way.
The last issue we came across was the shackle hitting the body mount when fully drooped in

The front axle had been moved 1 1/2 inches forward with the new suspension setup. That, plus the fact that we had a lot more travel, required us to purchase a new driveshaft. We turned to the Driveshaft Superstore in Phoenix to get us out a new driveshaft that was the correct length and could deal with the more extreme angles this new CV 'shaft will see. They set us up with a 7-inch working travel yoke and 40-degree high-angle hybrid CV made from a combination of 1/2-ton and 3/4-ton parts.

SOURCES
Advance Off-Road	Driveshaft Superstore
Baja Shop	Energy Suspension 1131 Via Callejon San Clemente CA 92673
Bilstein 14102 Stowe Dr. Poway CA 92064 858-386-5900 www.bilstein.com	Off Road Design www.offroaddesign.com
Deaver Spring