Another c3 steering box high point question

[William S.]

I read the long thread on this question and have a similar question.

I just had the steering box on my 1969 rebuilt by a reputable shop. The alignment was fine before I took it off. When I reinstalled it with the flat spot at 12 o'clock there was a lot of drift when driving straight. I took the box off and from the high point the shaft turns two turns to the right and 1 3/4 turns to the left. From what someone said in the other thread this difference isn't enough for the worm gear to be a tooth off the sector gear. Does the flat spot need to be exactly halfway between the two end points?

I was going to take it back where I got the box rebuilt. Is it likely that it was set up incorrectly? The alignment was ok before I took it off.

[Jim S.]

Re: Another c3 steering box high point question

The Corvette manual gear was originally manufactured with the gear exactly on center when the flat spot was at 12 o'clock. Unfortunately, after 30+ years, you are getting to be at the mercy of whoever manufactures replacement parts (it isn't Saginaw.) The flat spot at 12 o'clock is supposed to be the way you can determine on-center.

Unfortunately, all of my answers are getting to be somewhat wishy-washy. I can't even guess if the parts are NOS or if the more recently manufactured parts are correct.

Jim

[William S.]

Re: Another c3 steering box high point question

That was really my question, are these things manufactured so that the flat point will be at 12 o'clock exactly at the high point? I think it is about 1/8 turn off, which I think also means it was installed correctly because if the worm gear was a tooth off center I think it would be farther off.

I think that I'm just going to take the top off the steering box and look. If the flat spot isn't at 12 o'clock at the high point it won't match up with the steering wheel and I'm not sure what to do about that. The steering column has a flat spot as well so there's only one way to orient it.

[Jim S.]

Re: Another c3 steering box high point question

From your first comments you mention that the from the high point of the gear there is about 2 turns to the right and 1 3/4 turns to the left. How did you determine the high point? Did you use a torque wrench? Or was it from the point that the flat was at 12 o'clock?

Your gear should have 3.58 input shaft turns lock to lock and your pitman shaft should rotate 80.8 degrees at the same time. From your first comments, you have 3 3/4 turns (pretty close.) Can you determine if your gear meets the 80.8 degree travel specs?

Saginaw Steering Gear Division stopped making manual steering gears around the same time as the C3 went out of production. The manual gear business was sold off at that time. As you can imagine, after 26 years there aren't many engineers at Delphi Saginaw who even remember manual gears let alone expertise in this area.

Try to answer the above questions and maybe I can contact a retiree who might make sense from the problem.

Jim

[William S.]

Re: Another c3 steering box high point question

Jim,

I was measuring the turns from where the flat point was at 12 o'clock. I will check on teh 80.8 degrees tonight. The number of turns is about what you mentioned. Either the flat spot isn't at 12 o'clock or the the number of turns from high point to lock is different between right and left. Do you have a guess as to which is more likely?

As I said, I can take the cover off and remove the mystery, but if the flat spot isn't at 12 o'clock when the gear is at its high point, I will have a problem with steering wheel alignment.

Thanks for your help.

[Timothy B.]

Re: Another c3 steering box high point question

William, For what it's worth and from memory, my 1963 corvette steering box may be the same way (a little more one way than the other when turning lock to lock) The tension nut on the top cover is adjusted using inch pounds so you may want to think twice before taking anything apart. Align everything by the book and adjust tie rod ends to center tires straight.

[Jim S.]

Re: Another c3 steering box high point question

William,
The Corvette assembly drawing calls out equal travel either side of center. Center is also defined as the flat spot at 12 o'clock.

I do not know a lot about manual gears. I do know that there were a few Chevelle power steering gears that actually had unequal travel either side of true center. The unequal travel was accomplished with big spacer rings inside the gear that restricted rack stroke in one direction. The big die cast end plug was made thicker and thinner to accomplish the exact stroke distance in the other direction.

I do not know if unequal travel was even offered with a manual gear. Also I do know that the C2/C3 Vette gear was pretty unique. The housing was Corvette only. I believe that pitman shaft was Corvette only as well. If the worm (input shaft) was unique to Corvette it is unlikely that anyone could stuff the wrong parts into a Corvette gear housing to end up with unequal travel. Now that isn't to say that someone could stuff incorrectly manufactured parts into a Corvette gear housing.

I still have two calls into retiree engineers in hopes of finding the right person to help us.

Jim

Jim

[Joe L.]

Re: Another c3 steering box high point question

William,
The Corvette assembly drawing calls out equal travel either side of center. Center is also defined as the flat spot at 12 o'clock.

I do not know a lot about manual gears. I do know that there were a few Chevelle power steering gears that actually had unequal travel either side of true center. The unequal travel was accomplished with big spacer rings inside the gear that restricted rack stroke in one direction. The big die cast end plug was made thicker and thinner to accomplish the exact stroke distance in the other direction.

I do not know if unequal travel was even offered with a manual gear. Also I do know that the C2/C3 Vette gear was pretty unique. The housing was Corvette only. I believe that pitman shaft was Corvette only as well. If the worm (input shaft) was unique to Corvette it is unlikely that anyone could stuff the wrong parts into a Corvette gear housing to end up with unequal travel. Now that isn't to say that someone could stuff incorrectly manufactured parts into a Corvette gear housing.

I still have two calls into retiree engineers in hopes of finding the right person to help us.

Jim

Jim

Jim-----


Are we talking here about a flat spot on the splines of the wormshaft?

[William S.]

Re: Another c3 steering box high point question

Joe,

Yes. The flat spot on the worm shaft is not at 12 o'clock halfway between the two end points. I'm trying to figure out whether the high point is when the flat spot is at 12 o'clock or halfway.

[Joe L.]

Re: Another c3 steering box high point question

Joe,

Yes. The flat spot on the worm shaft is not at 12 o'clock halfway between the two end points. I'm trying to figure out whether the high point is when the flat spot is at 12 o'clock or halfway.

William-----


Is your car a VERY late 1969? I don't think that the flat spot was used on 63-L69 wormshafts.