Reply to "bump steer kit"

Larry, your description of bump steer is correct. Bump-steer cannot be totally eliminated from any car but it can be minimized, by two methods. The first is two shim strips between the rack mounts and the underside of the front trunk floor where the rack is held by split-clamps. Each car will ideally need a slightly different thickness, but when the factory addressed this in mid-'73, they used about 5/16" thick shims. This seems to work to eliminate most bump-steer on most Panteras. But it causes three mini-problems. First, it also modifies the Ackermann-toe since the trunk floor is slanted. So shimming the rack not only lower the rack (for bump-steer correction), it also moves the rack forward (which changes Ackermann. On a street car, you'll never notice an Ackermann change). The second problem is, shims require 4 ea. 5/16" LONGER rack-mount bolts for the same thread depth as stock, for safety. The third problem with using rack-shims is, it misaligns the holes drilled thru the front subframe to hold Bill Stropp's rack-brace on U.S. cars. To rectify this, either re-drill 4 more holes, or cut the same amount of material off the outer rack-clamp surfaces where the bolt-heads touch. This allows the original rack-brace holes to be used, and also the original bolt lengths.

A different way of correcting bump-steer involves removing both metric tie-rod ends and replacing them with 1/2-20 SAE heim joints. These particular metric and SAE threads are so close in dimensions, SAE rod-ends and jam nuts will screw onto the metric steering rack threads without interference and has worked fine on our car for 3 years now. Use a Speedway Motors tierod-conversion stud to go into the tapered holes in the steering arms, and make your own shim-stack to fit between the heim joints and the steering arms. Such a set-up is sold by D. Quella for bump-steer adjustments, but his kit uses an allen bolt thru the steering arms, which means drilling the tapered hole out of the arms- an irreversible change. By using the Speedway conversion stud (p/n 535-AK35; $4.99 ea) no irreversible drilling need be done and you can go back to the stock setup at any time. With heim-joints, I recommend also using Speedway's heim-joint seals (2 per joint) for weather protection. Again, each Pantera will ideally need its own shim-height but about 5/16" thickness seems to be a one-size-fits-all, at least for street cars. This mod does not change the Pantera's Ackermann, if that concerns someone. Be sure to readjust toe-in after any front end changes; about 1/2 turn on ONE steering rod will get you close enough to drive to an alignment shop.