Spring-Over Axle lift on an early model Isuzu.
Short Cuts
Authoring and Photography By:Dan Houlton
First Published: April 2000

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Showing some flex (86079 bytes)
An early model Amigo showing a little SOA flex in back.

One of the first things an aspiring off-roader wants to do to their Isuzu is lift it and fit bigger tires for more ground clearance. Options for lifting your early model Amigo, and Isuzus in general, are somewhat limited. There are a couple companies out there that have lift kits for the leaf sprung Isuzu's, but they do it the same way. They use additional leaves and / or extended shackles in back and you crank the torsion bars for lifting the front. Calmini is I think the oldest supplier and they go one step further by supplying new upper A-arms for the front. These arms are longer than stock and they allow you to keep the front end camber in check when you have the torsion bars cranked all the way up.

While there's not much you can do with the front without some serious cutting and welding, the back can be improved upon. This article covers the lifting of a spring-under-axle 4x4 Amigo using a Spring Over Axle (SOA) lift in back and parts of a Calmini lift kit for the front. The pictures and details are of a '94 Amigo, but they will apply to the other leaf sprung Isuzus as well.

Basically, a SOA lift moves the leaves from under the axle to over the axle to provide the lift. Advantages include much more ground clearance under the axle tubes and, because you're not adding leaves, you retain the stock ride rather than getting a stiff jarring ride that add-a-leaves or re-arched springs can cause.

The SOA provides a lot of lift, around 6". While some people may really like this, it's a bit too much for those of us who wish the vehicle to remain somewhat level. The front can only be lifted by a max of about 3" so unless you're planning some major modifications like building new, longer A-arms or doing a solid axle swap up front, you'll want to reduce that 6" to something more like 3" - 4". For some people, it turns out not being much of an issue. On older vehicles, the springs may be so old and have sagged enough that the SOA lift is not too high. I'll examine the options for reducing the lift below.

The Calmini kit lifts the front of the vehicle by cranking the torsion bars and it includes a set of longer upper A-arms, braided steel brake lines, new bushings, a new cross-member, new heavy duty torsion bars and the required hardware to complete the job. The kit lifts the rear with additional leaves and extended shackles and it includes all the required hardware (u-bolts, bump-stop drop brackets, etc) for the back.
SOA clearance  (33991 bytes)
Here you can really see the clearance gained by moving the springs over the axle.

In researching how to lift my Amigo, I decided that although additional leaves and extended shackles is a very common method for lifting a leaf sprung axle, I did not want to do mine this way. My main reasons were:

  1. Adding leaves gives you even less ground clearance under the spring packs. The springs, spring perch, top plate and u-bolt ends all extend below the axle tube. Adding leaves to the spring pack makes them extend even lower and reduces ground clearance.
  2. Adding leaves to a spring pack makes it substantially stiffer. This may be a good thing depending on your vehicle, the condition of the springs and how you use it, but I did not want additional stiffness.

Axle wrap is one of the biggest concerns with a SOA lift. Axle wrap is when the torque on the axle tube tries to rotate the axle pinion up when under power. This twist causes the leaf springs to twist up into an 'S' shape then snap back which leads to loss of traction, wheel hop and usually broken parts. With a SOA lifted vehicle, axle wrap (also called spring wrap) is usually worse because there is more leverage for the twisting axle to work against the springs.

This is usually a problem with big engines, lots of torque and/or big, meaty, gnarly, grippy tires. Where it is a problem, an anti-wrap device of some sort can be used. Axle wrap is not *much* of an issue for us. It is there and you may notice it in a high traction spot in low range climbing a steep ledge, but for the most part we're unaffected by it with our relatively low output engines. I personally have looked at several different anti-wrap designs but have not yet felt an urgent need to apply one.

For the front, my only choice was to crank the torsion bars for more lift. Even the Calmini lift kit achieves it's lift by this method and their longer upper A-arms let you correct your camber after doing so. The other items like the heavy duty torsion bars and new front cross member are not needed and in my opinion are detrimental to off-road use. The strait cross member, while being very stout, reduces ground clearance by several inches over the curved cross member it replaces. So far, I have not found the stock cross member to be lacking in strength in any way so the replacement is not needed.

The heavy duty torsion bars make for a stiffer ride than the already overly-large stock torsion bars. In fact, I know a couple others that have gone the opposite direction and use the even smaller than stock 2wd model torsion bars to get better wheel stuff on the front. The stock torsion bars when dialed in for lift twist much further than designed as the wheel gets stuffed into the wheel well and they get very stiff very quick. By comparison, the 2wd torsion bars don't ramp up in spring rate so fast as they twist so the front wheel will stuff into the well easier. One person I know who uses them also has a hundred pounds of winch on the front bumper and has seen no sagging of the 2wd bars even after several years.

For my lift, I did all my own work in back and I bought the Calmini lift kit *only* for the a-arms for the front as there was no other option. I did save a bit by buying their 3" upgrade kit rather than their full 3" kit. The upgrade kit is intended to upgrade one of their 2" kits to a full 3" and it includes the A-arms in it. I also used the braided stainless brake lines for the front although stock lines should work just as well.

Because there isn't really much to lifting the front, this article will initially concentrate on the SOA conversion for the back. The front is literally just replacing the upper a-arm and cranking the torsion bars and is very similar to how the new models are lifted as well.


Getting Started
Pulling the axle (30215 bytes)
Pulling the axle out.

The first step is to get the back of the vehicle up in the air and secure it with jack stands, wheel chocks, etc. You may want to lock the hubs and put it in 1st gear, 4-low as well so the front wheels help to keep it in place. Leave the parking brake off as its cables have to be removed and it won't do any good anyways since the rear axle is off the ground. It's best if the stands used are the heaviest duty ones you can find as these have a larger base on them. I found some 6-ton stands that work very well for this as they have a large 10" x 12" foot print vs 6" x 7" for my 2¼ ton stands. Place the stands under the frame far enough in front of the rear axle to get the rear end well into the air. This makes it easier to roll the axle out backwards under the truck.

The next step is to start disconnecting the lines to the axle.  The parking brake cables, hydraulic brake line, diff breather hose and the ABS sensor wire (if you have ABS) all have to come off. You might want to find a package of small assorted sized corks to plug the hard brake line on the frame to keep it from continually dripping on you. I just wrapped it with plastic and a rubber band and that worked alright but still dripped a bit. Remove the shocks and the U-bolts and the axle is free, sitting on the springs. If you have, or have access to an impact wrench, use it. Those U-bolts take a long time if you're doing it with a breaker bar and ratchet. The impact wrench can spin the nuts off quickly and easily. You'll also love it even more when it comes time to put them back on.

Although the picture above doesn't show it, the easiest way to remove the axle from this point is to support it under the differential with a rolling floor jack while you unbolt the shackles at the rear of the springs. This will let the rear of the springs pivot down and you can roll the jack out backwards with the axle sitting on it. It will balance pretty well, but you might want an extra set of hands to make sure it doesn't fall or pivot off the jack. A larger 3-ton or better jack will help here as they usually have a much larger pad than the smaller jacks and the axle will rest on it more securely.
Empty belly  (64506 bytes)
An empty undercarriage.
Preparing the axle (58590 bytes)
Preparing the axle for the spring-over.

I also removed the spaghetti mess of an exhaust system it had in preparation for a new one when I was done. The fuel tank was removed in preparation for raising it a couple inches. Things look pretty roomy once you get all these things out. Note that the fuel tank and exhaust don't have to come out to do a SOA. I was doing these modifications to them at the same time so I took it all out to make it easier to work underneath.

After rolling the axle out you can support it with milk crates, blocks or whatever else you have available to make it a little easier to work on. Depending on what you plan to use for spring pads on top of the axle, you may need to remove the old ones from the bottom.

To remove the old pads, use a small wheel grinder with the thinnest wheel you can find or better yet use an air driven cutoff wheel. A Dremel tool with one of those large 2" or so cut-off wheels might work as well, but it'll take a long time. There are two weld beads on the old pads, one on the front and one on the back. Carefully grind away the weld on one side and watch that you don't go so deep as to grind into the axle tube. You only want to go deep enough to cut the weld.

If you look real close, you'll probably see a hair line crack where you get completely through the weld. You can use a chisel to break it loose when it starts to look close. It'll make a little "click" and pop open 1/8" or so. Do the same to the other side and you can remove the spring pad. Clean up the remaining weld on the axle tube with a grinder to make it smooth again.

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