Hi Jim,
I have a couple of questions on rebuilding my manual box off my 69.

I have it apart and wanted to know what is determining factor in replacing the rack? the teeth show signs of wear but what determines what's good or bad, is there a dimension to check?

Also I thought you had rebuild instructions on the web other then the GM procedures, do you have a link to these?

This box has not been off the car since I bought it back in 1981 and I don't think it was ever off. The car has a lot of early 69 parts but the box has an aluminum cover without the flat spot the later cars have? Is there any type of date coding on the boxes does this sound like a correct box?

Thanks in advance Jim and Happy New Year! :cheers:
Gary

 

I'm afraid you may be expecting a bit more expertise than I can provide. I understand the design and theory of the steering system operation but I am a bit short on experience with respect to analyzing 34 year old manual gears by eMail! I really can't describe how much wear on the pitman shaft teeth is too much or excessive. The surface of the teeth should be smooth. Pitting from corrosion, wavyness, or scuffing is not acceptable. The part number for the original pitman shaft is 7808317. I can't seem to get the {Non-supporting vendor} websight to work tonight so I can't confirm if it is still available.

In late 1969 or early 1970 Saginaw changed to the aluminum side cover.

According to my part print there should have been a metal tag held in place by one of the side cover bolts. There should be the part number of the gear 7819668. Also there should be a date code xxx-x where the first three numbers are the day of the year (001 through 365) and the last number should be the year (5 for 1975). Since my 1975 is in storage, I can't check if it had a tag or not. (Quite frankly, I don't remember a tag.)

Check you gear input shaft. Originally the input shaft was full round with 30 serrations. Sometime in 1969 the shaft (and the flexible coupling) was changed to include a flat milled onto the shaft. The flexible coupling was machined with an equivalent flat to match the input shaft. The flat carried through until the end of C3 production.

New couplings with a flat will not attach to an old full round input shaft with 30 serrations. However, an old coupling with the full round serrations will assemble to a new shaft with a flat. The flat was added to aid in assembling the coupling to the gear. Also it provides a degree of steering safety since it is possible to wipe out serrations. But a flat pretty much insures that the coupling can never slip completely on the gear input shaft.

Happy New Year,
Time to drink some champagne.

Jim Shea

 

Thank you Jim and happy New Year!
Your help is very much appreciated. I will clean up the parts a take a closer look under our shop mag. With the new forum rules this can be a problem sourcing parts. There was no tag on the cover but I don't recall looking at the shaft for any stampings. This is an aluminum cover with the full round shaft.
I understand it would be nearly impossible to inspect a part per email or posting, I just didn't know if there were any "tricks of the trade" to be aware of? Thanks again just the same,
Gary :cheers:

 

So you have an early 1969 input shaft (full round serrations) with an aluminum side cover (also a running 1969 change). If you ever replace the flexible coupling, just be sure to get the early full serration part 7806391 not the one with the flat (7818568) from your local dealer (whoops a non-supporting vendor) or from any other competent Corvette part vendor.

I'm not sure what you mean by "looking at the shaft for stampings".

Jim Shea

 

Thanks Jim, I already have one of each GM joint assembly. I was referring to any numbers that be cast/stamped on the shaft,I just cleaned it real quick yesterday and didn't get a good look at it. Maybe today I'll get a chance to take a closer look at it.
Gary