Hears a question for all you engineering/metalurgist buffs. I recently had someone rebuilt the steering box in my 63. I later found out that he used a NOS sector shaft from a later C2. Now as I understand it, this shaft is a little longer, and it would therefore have to have been ground down on the inside face in order to fit the 63 box. I know the shafts are case hardened but what happens to all the proper surface tensioning and hardening in the area that has been machined. My guess is that the ground area probably looses it case hardening, (probably related to temperature and amount removed) so I think that wear on that surface is it's most predictable fault. I'm more worried about failure than wear! Is this now a safety issue? There is every chance, that this car will be raced, and therefore, the steering really put to the test. Any thoughts on whether my life (or someone elses) will be worth of plug nickel with the potential of shearing off the pitman arm under extreme conditions. Regards Larry
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Re: Integraty of a 63 Sector Shaft after Modificat
I cannot visualize the ground area from your description. You said the sector was ground on the "inside" because it was "too long". Can you expand on your description?
Duke -
Re: Integraty of a 63 Sector Shaft after Modificat
Larry-----
There were only two Pitman shafts(sector shafts)ever used on 63-82 Corvettes. The first was GM #5677096. This shaft was used well into the 70s, but I can't tell you exactly when, at the moment. This part was replaced in SERVICE and PRODUCTION by GM #7812838. As far as I know, the latter shaft is completely interchangeable with the earlier one and will service ALL 63-82 Corvette steering boxes. So, I really don't understand what the problem is here.In Appreciation of John HinckleyComment
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Re: Integraty of a 63 Sector Shaft after Modificat
Duke, The shaft looks as if it has been reduced in diameter its entire length. When looking at it, its shiny hardening is gone leaving a matt finish When viewing a cross section of the box itself the shaft appears to have been ground to fit within the housing bushings. I also reviewed the part numbers in the service manual as Joe mentioned. I'm wondering if the sector shaft after 72 isn't a bit thicker to accomadate the increased weight of the car? Maybe this is what may have been used. All I can get from the mechanic is that it was the correct shaft but it had a factory "flaw" that needed correcting. Regards LarryComment
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Re: Integraty of a 63 Sector Shaft after Modificat
Thanks for the details, Larry. Given Joe's post (below) grinding the pitman shaft sounds a bit "fishy". If the shaft was "flawed" it should have been replaced. Overall strength of the part will not be severely affected by grinding off the hardening, but any wear surfaces that contact bearings/bushings would likely wear much more rapidly. Given the type of service you invision, maybe you should consider obtaining a new core box and properly rebuilding it.
Duke
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