70 Control Arm Shaft Finish

[Allen N.]

I am doing a frame off restoration on my 70 BB convertible. I have it torn down to a bare frame and am working on the control arms. On the lower control arm shafts, I have sandblasted the one on the right and wire wheeled the one on the left. Does the wire wheeled one have the correct looking natural finish? If not, what should an original natural finish look like? Is there a good method to get the sandblasted shaft to look like an original natural finish?

The judging guide says the upper control arm shafts can be either natural or painted. Based on my research, I am leaning towards restoring mine to natural as it seems like there are more original cars with natural upper control arm shafts. I would appreciate comments from early 70 cars that have original upper control arm shafts as to if yours are painted or natural. I emailed Terry McManmon and his are natural.

Thanks,
Allen

[Paul O.]

Re: 70 Control Arm Shaft Finish

I do not have a photo of a unrestored natural finish with no rust or a new lower shaft but here is what a typical forged shaft would appear. It is an idler arm but it is typical for how an original finish would appear.

[Edward J.]

Re: 70 Control Arm Shaft Finish

Allen, I would sand blast them to remove all the rust and then take some steel wool to them after, don't polish them just enough t make them look forged, and if you don't want the to rust I would spray them with some satin clear, this is not how the factory does it; but myself I put a lot of time and effort when restoring these type of suspension parts.

[Joe L.]

Re: 70 Control Arm Shaft Finish

Allen-------


The original appearance of these forged parts is very difficult, if not impossible, to accurately restore.

Attached is an NOS example of one of these shafts currently for sale on eBay (I have many NOS examples of this shaft but it's a lot easier for me use a picture off eBay than to dig out one of mine). This particular shaft is the I beam style rather than the "flat" style you picture but the appearance is the same. The pictured shaft does suffer from minor corrosion but you can still get a good idea of the appearance.

By the way and incidentally, both the I-beam and "flat" style shafts were of the same forging number and were used interchangeably. Sometimes, both styles were originally used on the same car.

http://www.ebay.com/itm/1963-82-Corvette-Lower-Control-Arm-Shaft-Gen-GM-Part-3749296-NOS-/162387420561?hash=item25cf0b6591:g:L-cAAOSwnHZYmhVj&vxp=mtr

[David C.]

Re: 70 Control Arm Shaft Finish

I have a 1973 with one upper shaft with a relatively bright metal finish, and the other side of the car in a painted black finish. Apart from the possibility that one was replaced, could this have been a production variation?

[Richard R.]

Re: 70 Control Arm Shaft Finish

Allen,

I am working on a 69 and for suspension parts that should be natural I bead blasted the parts clean, then treated them with Rust Mort. After waiting a day, I rinsed off the rust mort with tap water, touched up any places that may need it with steel wool, then coated with eastwood's satin clear. I can't attest to how well they will hold up since the car is still in process but the final look gave that mottled blue gray appearance that is desired.

Rust Mort is available at auto parts stores etc.

Rich


Rich

[Joe L.]

Re: 70 Control Arm Shaft Finish

I have a 1973 with one upper shaft with a relatively bright metal finish, and the other side of the car in a painted black finish. Apart from the possibility that one was replaced, could this have been a production variation?

David------


I think it's possible. The control arms were assembled with bushings and shafts (but not ball joints) at some component assembly site other than St. Louis. I highly doubt the left and right sides were assembled in pairs. At St. Louis they were certainly not pulled from bins in pairs. So, side-to-side variation was very possible. Of course, it's also possible that your car suffered front end damage at some point and one of the arms was replaced. Further scrutiny might be in order to observe tell-tale signs of the latter.

[Allen N.]

Re: 70 Control Arm Shaft Finish

Thanks for all the responses. I have been trying baking the parts at 250 to 270 for 30 minutes to an hour and then wiping them down with used motor oil. I found this method in an August 4, 2014 thread. I have the parts setting with used oil on them overnight and will see what they look like in the morning.

Thanks,
Allen

[Ron G.]

Re: 70 Control Arm Shaft Finish

Although upper control arm shafts are excepted weather natural or black, the majority that I have witnessed are always black on top and natural on the bottom. If they are black on top, then the bushing washer and bolt or black as well. I have always seen the bottom shops always natural as well as the bushings washers in the both are black oxide