Hot Rod Wishbone Suspension - Better 'Bones: Part II - Tech

Alan Johnson uses a plumb bob to locate the exact center of the rear axle housing; a line is then scribed on top of the framerail and down the side of the framerail.

A second measurement is taken from the rear of the framerail to the center of the rear axle. Precise measurements are imperative in a non-adjustable suspension installation.

An adjustable slide bar was used to prop up the rear of the axle housing holding the front driveshaft yoke at 3 degrees.

A simple angle finder provides us with the information needed to set the pinion angle at 3 degrees.

Certain the axle housing is at the proper wheelbase and perfectly square to the framerails, two short pieces of 1/2-inch box tubing were welded from the framerail to the axle housing to ensure nothing would move during the fabrication process.

Perfection is in the details, and to that end Alan Johnson uses thin nylon washers between the new rear wishbones and the brackets. This ensures the pieces will slide into place easily after the brackets have been prepped and painted.

The new rear radius rods are mounted to the front tubular mount. Since the tube is not yet welded in place is can slide fore and aft to locate the bars perfectly.

The outer bracket is installed on the wishbone and put in the proper position on the axle housing.

A simple screw jack holds the bracket in place while the bracket is moved left and right to the proper location where there is no twisting or binding of the radius rod.

With both of the new radius rods from Perfection Hot Rod Parts in place it was easy to see why this would be a huge improvement to any vintage-style hot rod.

Here we see the inner and outer brackets in place ready for some tack welding. Both radius rods were tack welded in place, locating the rear axle perfectly, then the lower tube of the center crossmember was tack welded.

Installing the Posies rear crossmember was next. Since the piece would have to be trimmed to fit, Johnson finds the center measurement from the framerail. No, he's not measuring into thin air, there is actually a laser beam hitting his tape measure.

The centerline of the rear crossmember is exactly 7 1/2 inches behind the center of the rear axle. That line is scribed down the side of the framerail.

After trimming the Posies rear crossmember to fit the frame it was leveled and tack welded in place. It is important that all suspension components travel on the same plane to prevent unwanted binding.

The rear crossmember is in place, ready for the buggy spring suspension, but first we need spring hangers on the rear housing.

The rear spring hanger is positioned with the center of the shackle boss exactly at the center of the rear crossmember, which in our case was 7 1/2 inches.

As you can see the spring hanger is very close to the axle flange in this installation. The gusset is also tack welded in place, which keeps the bracket perfectly square to the rear axle tube and prevents flexing.

A piece of flat stock across the bottom of the radius rod mounts serves as a measuring point to position the shock absorber mount between the plates.

The upper shock absorber mount was fabricated from a piece of a bar stock. One end was pulled flat to provide a surface to mate with the crossmember, while the other end was turned down to the diameter of the Bilstein shock absorber eye.

With the two Bilstein shocks bolted in place we are ready to locate the antisway bars. One can't help but marvel at how good looking these wishbones are when attached to a Winter's quick-change rear.

From the side we can see all the critical mounting points of the rear suspension. It is a study in simplicity and fine design.

The new aluminum dog bones from Perfection Hot Rod Parts by Alan Johnson are a new take on an old part. Smoother, stronger, and better than the old dog bones, but with that same great vintage flavor.

Option one for the antisway bar is the forward-mounted bar. The side mount for the bar is located on the inner side rail. At Johnson's Hot Rod Shop they drill and tap the side rail to bolt the bracket in place. Then, they go back and drill out that hole and weld in the final threaded bung, thereby ensuring a perfect location.

Here we see the lever arm and dog bone attached to the radius rod bracket. This completes the antisway bar installation in the forward mounting location.

Option two is a rear mounted antisway bar, and this seems to work best with fenderless cars. The sway bar mounts through two pocket mounts welded in the frame. A urethane bushing isolates the bar from the metal.

The sway bar levers are adjustable on the splined bar and the dog bones connect to the spring hanger bracket. The sway bars and lever arms come in various styles and are available from Perfection Hot Rod Parts by Alan Johnson.

And here's the finished product. We can think of no finer way to locate your rear than with a pair of these great-looking radius rods by Perfection Hot Rod Parts and, with careful measuring and fabrication, you have a set-it-and-forget-it installation.