Rear Axle Yoke Cap Finish

[Anthony P.]

Ok so what would be the correct finish of the rear half shaft yoke caps from the factory for mid year big blocks? I said it should be a natural finish and a well known un-named supplier said black phosphate. JM is not clear on this item. Bolts are spelled out as zinc or cadmium with an A headmark.

[Wayne M.]

Re: Rear Axle Yoke Cap Finish

Ok so what would be the correct finish of the rear half shaft yoke caps from the factory for mid year big blocks? I said it should be a natural finish and a well known un-named supplier said black phosphate. JM is not clear on this item. Bolts are spelled out as zinc or cadmium with an A headmark.

Here's what is on a late '65 L78 (on the right) Caps look natural to me. These bolts are R B C. Current '65 TIM&JG doesn't mention steel cap finish or define hex bolt manufacturer.



j

[Anthony P.]

Re: Rear Axle Yoke Cap Finish

Wayne That is how I think it sould be thats enough proof for me! Thanks for the great shots this will help!

Tony

[Joe L.]

Re: Rear Axle Yoke Cap Finish

Wayne That is how I think it sould be thats enough proof for me! Thanks for the great shots this will help!

Tony

Tony------


Natural as-forged finish is what they were, except for machined surfaces. The same cap was used for 1965-79 (many 72-79 small blocks used the cap-type axles) and I have many NOS examples of that cap. All are natural. Keep in mind that natural finish varies. It can be a dark brown coloration to almost a "silvery", steel sort of color.

By the way, some of the aftermarket caps are, apparently, phosphate-finished. I've also seen some that appeared to be fully machined pieces and black-oxide finished.

[Anthony P.]

Re: Rear Axle Yoke Cap Finish

Thanks Joe!

[Terry M.]

Re: Rear Axle Yoke Cap Finish

Tony------


Natural as-forged finish is what they were, except for machined surfaces. The same cap was used for 1965-79 (many 72-79 small blocks used the cap-type axles) and I have many NOS examples of that cap. All are natural. Keep in mind that natural finish varies. It can be a dark brown coloration to almost a "silvery", steel sort of color.

By the way, some of the aftermarket caps are, apparently, phosphate-finished. I've also seen some that appeared to be fully machined pieces and black-oxide finished.

Perhaps billet pieces for some of the bling crowd.

Wayne's pictures of the stub axles got me to thinking. Those look like forged pieces. That would take some serious wack or more likely several wacks, to make that piece if it is forged. I would also expect it to be heat treated steel for strength which would make it even harder to form. And I do know the heat treating comes after forging and before final machining.

[Joe L.]

Re: Rear Axle Yoke Cap Finish

Perhaps billet pieces for some of the bling crowd.

Wayne's pictures of the stub axles got me to thinking. Those look like forged pieces. That would take some serious wack or more likely several wacks, to make that piece if it is forged. I would also expect it to be heat treated steel for strength which would make it even harder to form. And I do know the heat treating comes after forging and before final machining.

Terry------


It is possible these caps were cast nodular or ductile iron.

[Kenneth B.]

Re: Rear Axle Yoke Cap Finish

Ok so what would be the correct finish of the rear half shaft yoke caps from the factory for mid year big blocks? I said it should be a natural finish and a well known un-named supplier said black phosphate. JM is not clear on this item. Bolts are spelled out as zinc or cadmium with an A headmark.

The caps were cast iron. The caps were not painted & would have as cast look like the iron carrier. These were not forged steel. No reason to do anything else. Remember small blocks had U bolts.
KEN

[Kenneth B.]

Re: Rear Axle Yoke Cap Finish

Here's what is on a late '65 L78 (on the right) Caps look natural to me. These bolts are R B C. Current '65 TIM&JG doesn't mention steel cap finish or define hex bolt manufacturer.



j

How can one be a U bolt & the other be threaded. Is this a small block or a big block. all big blocks had the threaded caps.
KEN

[Joe L.]

Re: Rear Axle Yoke Cap Finish

Remember small blocks had U bolts.
KEN

Ken------


Not all small blocks had u-bolts for the axles. Through at least 1969 all small blocks used u-bolts. However, sometime after 1969 and certainly by 1973 some small blocks used the cap-type axles. In fact, my brother was once the original owner of a 1973 Corvette with base engine and 4 speed trans. It used cap-type axles. I have since confirmed that many small blocks used the cap type axles. I just don't recall, for sure, when it started.

[Kenneth B.]

Re: Rear Axle Yoke Cap Finish

Ken------


Not all small blocks had u-bolts for the axles. Through at least 1969 all small blocks used u-bolts. However, sometime after 1969 and certainly by 1973 some small blocks used the cap-type axles. In fact, my brother was once the original owner of a 1973 Corvette with base engine and 4 speed trans. It used cap-type axles. I have since confirmed that many small blocks used the cap type axles. I just don't recall, for sure, when it started.

Thanks Joe.
I was talking about the midyear cars. I will look at my 2 1970 lt-1's & see if they have caps. I do know that the cap style are hard to come by so i wonder why they are so scarce? I do know that they were CI & not steel.
KEN

[Joe L.]

Re: Rear Axle Yoke Cap Finish

Thanks Joe.
I was talking about the midyear cars. I will look at my 2 1970 lt-1's & see if they have caps. I do know that the cap style are hard to come by so i wonder why they are so scarce? I do know that they were CI & not steel.
KEN

Ken------


I expect you are correct on the cap material. However, if cast iron I'm virtually certain they would have been nodular, ductile, or malleable iron. If gray cast iron had been used, I think the u-bolts would have been a lot stronger.

[Joe L.]

Re: Rear Axle Yoke Cap Finish

How can one be a U bolt & the other be threaded. Is this a small block or a big block. all big blocks had the threaded caps.
KEN

Ken-----


I think that Wayne is just showing examples of the 2 types of axles. I don't think these came from the same car (unless it was an "aberration" created in SERVICE).

[Kenneth B.]

Re: Rear Axle Yoke Cap Finish

Ken-----


I think that Wayne is just showing examples of the 2 types of axles. I don't think these came from the same car (unless it was an "aberration" created in SERVICE).

I saw that also. I tried to delete the post but was not able.

[Kenneth B.]

Re: Rear Axle Yoke Cap Finish

Ken------


I expect you are correct on the cap material. However, if cast iron I'm virtually certain they would have been nodular, ductile, or malleable iron. If gray cast iron had been used, I think the u-bolts would have been a lot stronger.

It's all cast iron. No ductile iron was used till the 80'S. Gray iron was used because there was no need to make the casting less brittle bu you may be right. Albion Malleable made most Dana carriers which were made in FT Wayne In.,cases & maybe made the caps. I made patterns for most of the cases & carriers. Midwest Fdy in Goldwater made most of the master cylinders in the 60/70"s for Delco Moraine & brake caliper's.
KEN