Bending the Upper Control Arms

Another interesting site called Pole Position Racing Products that I came across makes fully adjustable control arms using turnbuckles for Camaros and Mustangs. With a little modifications, they may be made to work. My upper control arm is machined similar to theirs.

As an alternative to making turnbuckles from scratch, I found that my Dad's 1988 Buick's rear suspension has turnbuckles that could be adapted rather than start from scratch. They may be metric thread though but that shouldn't be a problem.

1988 Buick rear suspension uses turnbuckles

The control arms will be made out of 1" steel tubing with 3/16" wall mounted to the original 54's crossmember. I've spent a lot of time consulting with steering experts, machine shops, fabrication shops and safety inspectors. I had a scare when an "expert" hotrodder told me that the car will never pass inspection. It's supposed to be a daily driver so everything better pass. Talked to a guy who certifies vehicles and builds rods for a living and he says it's not a problem. So to the inspector's I go with my plans for their input. Better to be safe than sorry.

I finished the upper control arm. It is similar in design to the Pole Position one. In hindsight, I would build a new crossmember that fits 68-74 Nova control arms rather than machining all these parts - it would be simpler, faster and easier to replace parts if something breaks.

Upper control arm

Upper control arm - top view

On the frame the control arm mounting stud is about 1 1/2" long. I've machined a long 2" threaded sleeve that threads on to it (I've outlined the sleeve part in dark blue). At the end of the sleeve is the nut. The nut is actually part of the sleeve. You turn the nut, you turn the sleeve.

A 1" wide "donut" of SBR-80 rubber slides over the sleeve. The control arm end bushing slides over it and two large washers hold the rubber and control arm bushing from moving. I initially used SBR-80 rubber washers between the metal washers and the control arm but SBR-80 is too pliant and squeezed out when compressed. I switched over to a cloth/rubber style isolation material and it holds its shape quite well.

A large bolt locks the sleeve into place kind of like a reverse locking nut. Instead of a nut locking a stud, I have a stud locking a nut. The control arm end cannot slide off of the stud because of the retaining washers. I have thought of replacing the rubber with polyurathane but will wait and see. It takes about 30-45 minutes to assemble one side of the control arm cause the rubber expands inside the control arm end and I've run grooves on the inside of it to further stop sideways movement. The rubber expands into the grooves which help stop the rubber donuts from slipping out. Which just make it more tougher to try and slip on. We'll see how well everything works when its on the street.

There are 2 turnbuckles for adjusting the caster and camber. I have about 0.5" of adjustment in each for a total of about 4 degrees. This way if I screw up on the lower crossmember, I can still align the front end. In the above picture, you can see the top of the upper balljoint located at the bottom of the pix - it is black.

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Copyright March 2011 Eugene Blanchard