This is one of the stock Ford...
This is one of the stock Ford radius arms that positions one of the axles. The tops of the arms have to be modified for tie rod clearance.
Like many other aftermarket companies, Joe Morrow started his in a garage over 22 years ago. Ratical Tops was formed in 1987 and began manufacturing convertible tops for most every truck of the period, which they still sell today. In 1992, to better reflect their full line of products, the company was incorporated under the name AIM Industries, which they still go by today. In 1992 Chassis Tech was formed as the operation expanded and in 1994, AIM was the first company ever to put all four wheels on air with their Dodge Ram that was the feature truck on SEMA advertising in 1995. In 2002, the company was granted a patent for engineering the first AirStrut to replace a MacPherson strut. They also offer a variety of replacement dropped axles for just about any twin I-beam Ford from full-size trucks and vans to Rangers and two wheel drive Broncos. Airbagit’s dropped axles are a combination of fabricated I-beams with solid steel ends. Lengths vary depending on application as do the diameters of the kingpin and radius arm holes—our F-350 has 1-1/16-inch kingpins and 1-inch bolts securing the radius arms.
Here is the stock Ford shock...
Here is the stock Ford shock mount. It’s held to the arm by rivets made from Kryptonite—they’re really tough and we finally resorted to a cutting torch to remove them.
Installing the dropped axles is for the most part a remove and replace operation. However, there are some changes that are necessary. The tie-rod ends must be moved to clear the radius arms or the arms must be modified. In some kits, tie-rod end relocators are provided, in others, plates to modify the arms are included.
One Change Leads To Another
These pre-formed and drilled...
These pre-formed and drilled steel plates are used to modify the radius arms.
As we have said all along, our goal for the Hot Rod Hauler is to make it look cool but maintain its functionality. Now that we decided to install dropped axles we had another decision to make. Previously, we had removed a number of leafs from the rear springs to soften the ride and added air bags to maintain load capacity. So, while we installed the dropped axles, we decided to add air bags up front as well.
Airbagit.com offers universal air ride systems and parts as well as complete specific fit kits for everything from Alfa Romeos to Volkswagens, as well as foreign and domestic trucks. In most cases the kits are a 100-percent direct fit, but for some applications minor modifications are required. As our truck is a ’73 and a one-ton, we found that changes to the lower bag mounts were required, but in most cases it won’t be necessary.
With the top portion of the...
With the top portion of the arm cut away, the reinforcement plates can be put in place. The front holes align with those for the original shock brackets; those in the rear of the arm have to be drilled.
With the dropped axles installed, the front bags at ride height, the nose of our F-350 is down about 3 inches from stock—just what we were after. The problem is, even after reducing the spring pack in the back, the rear of the truck is just too high. So we’re going to fix it, which means moving the spring mounts up on the frame and notching the ’rails for clearance. We’ll show all that next month along with everything you need to know about installing and plumbing the air management system.
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To enclose the top of the...
To enclose the top of the radius arm reinforcements, we fabricated these “caps” and welded them in place.
Here, the modified left side...
Here, the modified left side arm is in place. The bolts were removed during welding and haven’t been replaced in this photo.
Included with the Airgbagit...
Included with the Airgbagit dropped axles is a kingpin replacement kit.
Good shocks are vital with...
Good shocks are vital with twin I-beam suspension. We opted for a pair of Bilstien monotube gas shocks.
With the modifications made...
With the modifications made to mount the air bags, new front shock mounts had to be fabricated. These were made from sections of tubing.
The new bottom shock brackets...
The new bottom shock brackets were welded to the modified lower bag mounts.
Shock studs available from...
Shock studs available from most parts houses attach to the new mount.
The upper mounts, also made...
The upper mounts, also made from sections of tubing drilled to accept the bushings on the Bilstien shocks.
With the suspension and shocks...
With the suspension and shocks at ride height the shock brackets were installed.
Important additions to any...
Important additions to any air bag installation are bump stops and travel limiters. We relocated the stock Ford brackets and bump stops to prevent bottoming out, the shocks limit extension when the truck is jacked up to prevent damaging the bags.