Steering box nut

[William S.]

Does anyone know what size the nut is that holds the pitman arm to the steering box on a 1969 (the steering box could be a 1970)? The one on there now is between 1 1/4 and 1 5/16. Is it a 1 9/32? I was able to take it off with a 32 mm, but the new one is too large for that socket and I don't want to force it.

Thanks.

[Joe L.]

Re: Steering box nut

Does anyone know what size the nut is that holds the pitman arm to the steering box on a 1969 (the steering box could be a 1970)? The one on there now is between 1 1/4 and 1 5/16. Is it a 1 9/32? I was able to take it off with a 32 mm, but the new one is too large for that socket and I don't want to force it.

Thanks.

William-----


1-5/16" SIX POINT socket is the size generally used for this nut. However, I agree with you; I don't think the nut is actually 1-5/16" across the flats. The nut measures 1-19/64", but that's for the GM #5667628. That's not the original nut used for 63-74. That nut was GM #258779. I THINK that nut was slightly smaller across the flats, but I'm not sure. In this case, they might be different part numbers for the same nut since the part numbers were assigned to different GM divisions.

I hope that Jim Shea is able to provide some information on this; this has perplexed me for years.

[William S.]

Re: Steering box nut

Any ideas on where I can find a 1 19/64 socket? It either has to be that or 1 9/32 or 33mm. I haven't had any luck locating any of them.

Thanks.

[Terry M.]

Re: Steering box nut

The 33 mm socket (6-point deep, impact) is available in many of the automotive parts mass merchandise stores (Auto Zone, Advance, Pep Boys, Checker, Kargan, Schuck's, [CKS], Murray's, etc). They are sold for use on FWD axle nuts. I have not had occasion to look for English versions of about the same size, but they might have them as well.

[Joe L.]

Re: Steering box nut

Any ideas on where I can find a 1 19/64 socket? It either has to be that or 1 9/32 or 33mm. I haven't had any luck locating any of them.

Thanks.

William-----


I don't think that any socket of 1-19/64" size is manufactured anywhere. In fact, I don't think that 1-9/32" is available, either. Even a 33mm is uncommon but may be available in a specialty type socket as Terry mentions.

[Terry M.]

Re: Steering box nut

I only know about them because 33 and/or 34 mm is the size of the rear axle nut on C-6, however, Bowling Green uses a 1-5/16 inch socket for this application. Usually with nuts of this size the tolerances for the distance across the flats are not that tight, so the exact socket size is not an issue.

[Jim S.]

Re: Steering box nut

The 1975 Manual Steering Gear Assembly drawing 7819668 has the 5667628 pitman shaft nut and 5697702 lockwasher called out on the drawing. The gear was shipped from Saginaw with the nut and lockwasher loosely assembled to the threads on the pitman shaft -- no pitman arm.

You mention that the earlier Corvette manual gear used the 258779 part number nut. That number would appear to be a GM Standards part number. All GM Divisions were strongly encouraged to use GM standards nuts, bolts, screws, etc in order to standardize fasteners and gain cost advantage with GM high production volumes. GM Standards had thousands and thousands of fasteners with GM assigned part numbers. 5667628 and 5697702 are Saginaw Division assigned part numbers.

So even though there were thousands and thousands of fasteners to pick from, your particular application might dictate a slightly different fastener from one called out by GM Standards.

For instance, just requesting a change to a different rust preventative coating from the GM Standards specification would dictate that typically the coating had to be changed on a whole family of nuts, bolts, screws, etc. This meant that you had get agreement from all GM using Divisions to change the coating on their GM Standard fasteners as well. Then only by "committee" action could the coating be changed on the GM Standards drawings. This might take many months - or years. In many cases, it was far easier to just pull your own part number and create a "non-standard" fastener.

In the old days, General Motors assigned blocks of part numbers to all GM Divisions. For instance, Saginaw Steering Gear Division had part numbers such as 566XXXX, 567XXXX, 568XXXX, 569XXXX, 780XXXX, 781XXXX, 782XXXX, 783XXXX, 26XXXXX from the 1960s through the early 1980s.

Jim