A-arm bushing modification (65-68 911/912)
Last Updated: 03/21/2013
During various parts of my '66 912 restoration/rebuild/upgrade project, I've come up against the curse of old car restorers-parts! Yes, I know, Porsches are actually one of the easiest classic cars to find restoration parts for (if you happen to be restoring a pretty popular year and model, that is), but some parts are getting hard to find-and DAMN expensive. Some simply aren't available-anywhere, at any price. Take front control arm bushings, for example-easy to find for most 911/912's from '68 on up-but for the really early cars ('65-'67), like my '66, uh-uh. Nope. Nada. Nein. Nyet. This was a bit of a roadblock to it's restoration-the original rubber bushings had long since departed, and I couldn't get the car back on it's wheels until I had SOMETHING to use for bushings.
After a few months of asking questions, doing a little research, crawling under a few cars, and making some measurements, I determined that I could use a set of bushings made for the control arms on the later cars-with a little work.
So, I ordered a set of 4 (2 front, 2 rear) Weltmeister polyurethane 911 front control arm bushings. When they arrived, I grabbed the A-arms and cross member and went to work measuring and fitting to see exactly what needed to be done.
The rear bushings' O.D., at 2.0" (51mm) was a perfect fit into the rear steel cross member-hey, that was easy. The I.D., though, was too small to fit over the control arm-so I took the bushings and one of the arms to a machine shop, where they carefully honed out the polyurethane bushings on a lathe to exactly 1.5" (38mm), which fit snugly (but not TOO snugly) over the control arms. Halfway done-now on to the front.
The front bushings were too big-both the O.D. and the I.D. Hmmm-this took a little thought. After considering several choices, I ended up clamping the bushings in a vise (front to rear) and using 2 heavy-duty cut-off wheels chucked together in a Dremel to cut a slit in the bushings' side wall, all the way from end to end. This removed exactly 0.075" (2mm) from the circumference of the bushings, effectively shrinking both their inner AND outer diameters by the same amount. When clamped inside the front control arm bracket that bolts to the front suspension pan on the car, the slit in the bushing closed up to zero, and the control arms now fit perfectly inside the I.D. of the poly bushings. The new I.D. of the bushing ended up at 1.395" (35mm), and the O.D. at 1.985" (50mm). Success! A healthy application of Weltmeister' poly bushing grease, and the front suspension was torqued back onto the chassis.
Credits: Clay McGuill