We recently received a call from Frank Aldana at Aldana Race Cars, in Orange, California, to let us know that as an aside to their usual business of building nostalgia Funny Cars, they'd recently been putting together not one but three early style hot rods, and they'd come up with a novel way to use a '40 Ford split front wishbone to locate both the rear axle and transverse spring. The main appeal of this method is its clean and simple appearance. It also has the effect of lowering a Model A chassis but, as the wheelbase is also altered, that's of little use to someone using a stock Model A body and frame unless they want the rearend 7 inches too far forward! It is of use to anyone either building a Modified or T bucket-style car, or using a Model A rear crossmember in another chassis, like a '32 for instance, where the crossmember is mounted behind the axle.
Apart from being a somewhat weak pun, the title of this feature alludes to the fact that using wishbones to locate an open-drive axle is a contentious subject. Why? Because when used in conjunction with a torque tube, which is bolted to the front of a banjo rearend and pivots about its forward-most point, there's no way the rearend can twist about its axis, but take away the torque tube and the axle wants to rotate, putting extreme stress on components that were never designed to be used in such an application. We've seen split wishbones used in this manner come apart, usually at the weld where the tube part joins the cast end, but also further forward when the thin tubing simply gives way. There are a few options to combat this, running from strengthening the 'bones or turning them into ladder bars with a second tube locating on brackets above the axle to fabricating a torque arm running forward parallel to the driveshaft, or installing a couple of upper arms in a kind of triangulated four-bar setup.
The guys at Aldana Race Cars had already split the wishbone before they called us, but saved the parts. Here's the original rear mount, which is no longer needed.
You'll see that we haven't decided which route we're taking with this yet because the chassis we used for this story will receive some serious alterations before we'll be able to make a decision based on what will work best as well as what will look right since this will end up a Modified with no rear bodywork to cover the rearend. So consider this the first installment in a Modified project, but with me having two project cars already on the go, it'll probably see sporadic progress, OK? Whatever, just be aware that if you use split 'bones on an open-drive rearend, you'll need some form of upper locator to combat torque.
Early Ford track rod ends are a time-honored method of locating split 'bones, and threaded bungs to accept them are available from many sources, including hardware supply houses.
By now you'll have concluded that the chassis we used is mine. Aldana Race Cars had modified the 'bones but had in-progress hot rods on both of their chassis tables and no chassis to mount the 'bones on, so I cunningly offered up a stock A chassis and '49 Merc rearend that was part of a pile of parts I'd been collecting to build a Modified for my fiancèe. I'd just hadn't been planning to start the build until I'd finished the Purple Pig. Ah well, she'll be pleased, and that's always a good thing!
