Question For Joe Please:

[Ralph B.]

Joe,

I have a similar concern that Lawrence recently posted (re: 69 rear Shock Mount Bad) which you replied:

" You can be sure that GM included the "knurled" area for a good reason. Is it absolutely critical to the function of the part? Probably not but I'd be reluctant to re-use a piece that was worn to the point that the "knurling" was completely ineffectual".

In my case the RH shock mount has a worn looking knurl not unlike the OP and would not bite, although the LH was fine.

The problem is magnified a bit because it's a F41 shock mount to my knowledge is not reproduced.

My question is this: what is the effect on function and can I assume there may be safety risks as well?

I recall reluctantly installing it knowing the knurl was compromised but unaware of any ramifications until I came across the post by Lawrence which got my attention.

There's a NOS RH 3829266 available (not cheap) which I'm ready to secure.

Thank you !!!
Ralph

[Joe L.]

Re: Question For Joe Please:

Joe,

I have a similar concern that Lawrence recently posted (re: 69 rear Shock Mount Bad) which you replied:

" You can be sure that GM included the "knurled" area for a good reason. Is it absolutely critical to the function of the part? Probably not but I'd be reluctant to re-use a piece that was worn to the point that the "knurling" was completely ineffectual".

In my case the RH shock mount has a worn looking knurl not unlike the OP and would not bite, although the LH was fine.

The problem is magnified a bit because it's a F41 shock mount to my knowledge is not reproduced.

My question is this: what is the effect on function and can I assume there may be safety risks as well?

I recall reluctantly installing it knowing the knurl was compromised but unaware of any ramifications until I came across the post by Lawrence which got my attention.

There's a NOS RH 3829266 available (not cheap) which I'm ready to secure.

Thank you !!!
Ralph

Ralph------


I really don't know the reason that Chevrolet engineering chose to include the "knurled" area on the shaft, so I can't really say what functionality is compromised when the area becomes worn. However, I feel quite certain that they had a good reason for doing it. A feature like this is not casually included on some engineer's whim. As I mentioned, I do not think the function is critical but any suspension component should be considered safety-related and, therefore, I don't like to accept any sort of compromise for these parts. As a matter of fact, I replaced both of the shafts on my car due to some corrosion-induced pitting on these shafts. This sort of pitting is very common on these shafts even for a car like mine which has lived its entire life in California.

As others have suggested, you should also check the spindle support shaft orifice for wear in that area.

As far as new shafts go, it is the F-41 shaft that is reproduced. Many years ago GM discontinued the 63+ standard shafts from SERVICE and replaced them with the F-41 shafts (although they continued to use the standard shafts in PRODUCTION to the end of the C-3 era). So, it's the standard shafts that are difficult to come by in NOS condition, not the F-41 shafts (Incidentally, I had NOS standard shafts for use on my car). The current reproductions continued the GM SERVICE parts practice and only the F-41 shafts are available for all 63-82 applications. However, the current reproductions do not include the GM forging number, but many of the later GM SERVICE shafts did not have it, either. A GM SERVICE piece without the forging number is really no different than the current reproductions, so no one should pay Big $$$$ just because it's in a GM box.

By the way, the original standard and F-41 shafts had the forging numbers embossed (raised characters in this case) on the shafts. For the F-41 shafts this was seen as "3829265-66" since, for F-41 shafts, the same forging was used for either side. The numbers "3829265" or "3829266" were NOT printed in ink on the unmachined area of the shafts. That method was used only on some later GM SERVICE shafts before the numbers disappeared altogether.

Incidentally, the original standard shafts had the raised forging numbers "3820929" and "3820930" depending on which side since the standard shafts were unique forgings for each side.

[Wayne M.]

Re: Question For Joe Please:

Pic of original standard shafts, 929 and 930.



c

[Ralph B.]

Re: Question For Joe Please:

Ralph------


I really don't know the reason that Chevrolet engineering chose to include the "knurled" area on the shaft, so I can't really say what functionality is compromised when the area becomes worn. However, I feel quite certain that they had a good reason for doing it. A feature like this is not casually included on some engineer's whim. As I mentioned, I do not think the function is critical but any suspension component should be considered safety-related and, therefore, I don't like to accept any sort of compromise for these parts. As a matter of fact, I replaced both of the shafts on my car due to some corrosion-induced pitting on these shafts. This sort of pitting is very common on these shafts even for a car like mine which has lived its entire life in California.

As others have suggested, you should also check the spindle support shaft orifice for wear in that area.

As far as new shafts go, it is the F-41 shaft that is reproduced. Many years ago GM discontinued the 63+ standard shafts from SERVICE and replaced them with the F-41 shafts (although they continued to use the standard shafts in PRODUCTION to the end of the C-3 era). So, it's the standard shafts that are difficult to come by in NOS condition, not the F-41 shafts (Incidentally, I had NOS standard shafts for use on my car). The current reproductions continued the GM SERVICE parts practice and only the F-41 shafts are available for all 63-82 applications. However, the current reproductions do not include the GM forging number, but many of the later GM SERVICE shafts did not have it, either. A GM SERVICE piece without the forging number is really no different than the current reproductions, so no one should pay Big $$$$ just because it's in a GM box.

By the way, the original standard and F-41 shafts had the forging numbers embossed (raised characters in this case) on the shafts. For the F-41 shafts this was seen as "3829265-66" since, for F-41 shafts, the same forging was used for either side. The numbers "3829265" or "3829266" were NOT printed in ink on the unmachined area of the shafts. That method was used only on some later GM SERVICE shafts before the numbers disappeared altogether.

Incidentally, the original standard shafts had the raised forging numbers "3820929" and "3820930" depending on which side since the standard shafts were unique forgings for each side.

Joe,

That's good news on the reproduction shafts which I wasn't aware of!

It's been a while; but, I remember the D hole in the spindle support was perfectly fine and although the shafts knurl didn't bite like the LH side it wasn't sloppy by no means, additionally I recall torquing the slotted nut to it's maximum limit to compensate?

Thank you !!!!

[Joe L.]

Re: Question For Joe Please:

Joe,

That's good news on the reproduction shafts which I wasn't aware of!

It's been a while; but, I remember the D hole in the spindle support was perfectly fine and although the shafts knurl didn't bite like the LH side it wasn't sloppy by no means, additionally I recall torquing the slotted nut to it's maximum limit to compensate?

Thank you !!!!

Ralph------


It's not the "D" hole that I was referring to. I was referring to the forward hole (the one that the "knurling" interfaces with).

[Joe L.]

Re: Question For Joe Please:

Pic of original standard shafts, 929 and 930.



c

Wayne------



Note the corrosion-induced pitting on the shock end of both shafts. This is exactly what I was referring to in my earlier post. In most cases, and more so than wear on the "knurling" which is also in evidence here, I feel this renders the shafts unfit for further use