After doing a bit of research online I came to the conclusion that the original front swaybar parts for the RC10 are in fact repackaged DU-BRO parts. To prove this hypothesis I bought some vintage new old stock DU-BRO parts off the interwebs and compared them to what I had sitting in the drawer for thirty years. Sure enough, the parts are identical.
Here we have Cat. No. 181, Cat. No. 180, Cat. No. 188, and finally we have Sleepy-Pooh Cat. Kitty-Pooh is a bit camera shy.
The original Edinger manual instructions describe a very difficult step in the swaybar assembly process. This single step daunted me in my youth and prevented me from ever successfully installing a swaybar on an RC10 up until now. The step in question describes the soldering of the hex ball end (Cat. No. 180 in photo) onto the end of a piano wire, typically 1.2 mm or so in diameter. Furthermore, the inside of the hex ball end has a hole threaded for a #4-40 screw, going in about 3 or 4 millimeters deep. The Edinger instructions recommend to use acid core solder and/or acid flux for the soldering operation.
I have no experience soldering using acid core solder but I consider myself to be an expert in soldering and repairing electronics for hobby use. I felt undaunted by the task at hand, which was to fabricate front and rear swaybars for the RC10, using original DU-BRO ball ends and ball cups, in order to accomplish period correctness.
I considered using modern swaybar hardware but decided against it for several reasons. First, the point of this RC10 restoration was to restore the car to be close to period correct at least in the shape of parts, unless serious design flaws in original parts were encountered or if original parts were very difficult or expensive to source. Second, having already conquered the task of installing swaybars onto several cars using ideal modern parts that I’ve come across, doing the same on this car would just be a walk in the park. It would not be a big challenge. Third and most important, the original front swaybar for the RC10 consisted of a threaded ball stud that screws into the front of the front A-arms. The A-arms have a small hole just next to the 2.8 mm hole that houses the front shock mount shaft. This smaller hole is under 2 mm in diameter and is meant for a #2-56 threaded screw/stud. I wanted to use this original hole instead of making a new one and/or instead of expanding the existing hole in size. Modern ball studs on modern cars of comparable size typically have ball studs with an M3x0.5 thread or a #4-40 thread. That’s an order of magnitude larger than a #2-56 thread. Furthermore, the original DU-BRO swaybar ball links used in original RC10 have a ball interface that is 3.90 – 3.95 mm in diameter, whereas the smallest variant of ball studs used in similar-sized cars today have the balls at 4.3 mm diameter, sometimes even 4.8 – 4.9 mm diameter. (Note: other non-swaybar ball studs on the RC10 have the standard 4.3 mm diameter.) The smaller balls used in a part as dainty as a swaybar and not requiring excessive strength seemed like an elegant choice. Because we would be drilling a hole in the rear A-arms for a swaybar ball link, a small diameter hole for a #2-56 screw seemed like a less intrusive modification than a larger diameter hole for a #4-40 screw.
After carefully making the holes in the rear A-arms and noting how perfectly symmetrical they were I originally mounted the DU-BRO #2-56 ball studs (Cat. No. 181) pointing back, meaning the ball was protruding to the rear of the car. I don’t have photos of that setup.
I heated up my 40 watt soldering iron and felt undaunted by the task at hand, which was to solder DU-BRO hex ball ends, internally threaded for #4-40 screw, onto a hand-bent 1.6 mm diameter piano wire purchased from local hobby store. 1.6 mm was chosen for the rear because it fits neatly into the groove intended for this purpose – a smaller diameter wire would not have fit as snugly. Furthermore, while 1.6 mm seems like a thick wire to use for a swaybar, my reasoning for this decision is as follows. I will explain this decision by asking a rhetorical question. If I were designing a beautiful woman and if I wanted this beautiful woman to have feminine attributes that clearly identified her as being a truly beautiful woman, would I exaggerate those attributes in order to eliminate the possibility of doubt as to her being a beautiful woman? Likewise, since I’ve been starved of having the ability of successfully installing a swaybar on an RC car in my youth, I wanted to exaggerate the swaybar’s ability and function now that I have the ability to install one properly. 1.4 mm diameter piano wire was chosen for the front, which fits snugly into the front groove.
(Continued in next post.)
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