I had a bit of spare time today so I started dismantling my A arms. To my surprise they had different shafts in them. Over the years I have spoken to 5 of the previous 6 owners and no one has ever mentioned anything resembling an accident or going in the ditch, etc. nor have they ever said they ever had any front suspension work done. These shafts look to be functionally the same but which one is correct for my early 63?
-
Golf is for those who can't play hockey. -
Re: 63 Lower A Arms - Which Shaft is Correct?
Well that explains it, strange as it may seem. Thanks Joe.
NormGolf is for those who can't play hockey.Comment
-
Re: 63 Lower A Arms - Which Shaft is Correct?
My car was the same way....Comment
-
Re: 63 Lower A Arms - Which Shaft is Correct?
Norm------
Something to keep in mind: the front suspension of 1963-82 Corvettes is derived from and very similar to the front suspension of 1958-64 full size Chevrolet passenger cars. Many of the components are the same including but not limited to a-arms, a-arm shafts and ball joints. So, the lower a-arm shaft in question here was the same for a 1958 Chevrolet Biscayne as it was for a 1982 Corvette. However, there were 2 configurations of that shaft, the "I-beam" and "solid bar". The part number and forging number was the same for both configurations---GM #3738505. Since these shafts were used for passenger cars in the 58-64 period, GM was making these things in HUGE numbers. During the 63-64 period they were also used for Corvettes but this was undoubtedly a comparatively small volume.
I believe that the "I beam" configuration was the original configuration used for passenger cars beginning in 1958. However, I have never confirmed that. Since there were so many of these shafts being made in the 1958-64 period there had to be many sets of forging dies. At some point most likely due to the need to replace dies or increase production, new dies were introduced to produce the "solid bar" configuration. I've always been surprised that the forging number did not change at that time but it obviously did not.
For some period of time, if not right through the end of 1982 Corvette manufacture, both configurations were being manufactured and used interchangeably. I suppose that for as long as the "I beam" dies were serviceable, they continued to be used. My 1969 was originally built with the "solid beam" style on both sides. I don't know what the situation was for other C3's but it would be interesting to know what owners find on original C3's.
During the period of 1958 until August, 1963, the GM #3738505 was available in SERVICE as a separate, individual part. It was also available as a UNIT consisting of the 3738505 shaft + bushings, retainers, and bolts as GM #3749296. After August, 1963 only the 3749296 was available until it was discontinued without supercession about 12 years ago. I have several NOS GM #3749296 [none for sale] and all are the "I beam" type. I don't know when these were actually manufactured but, almost certainly, it was after 1982 when PRODUCTION use ended. So, the "I-beam" shafts were still being manufactured at least right to the end of C3 PRODUCTION. Whether they were used in C3 PRODUCTION would be interesting to find out.In Appreciation of John HinckleyComment
-
Re: 63 Lower A Arms - Which Shaft is Correct?
... on both sides. I don't know what the situation was for other C3's but it would be interesting to know what owners find on original C3's. ... when these were actually manufactured but, almost certainly, it was after 1982 when PRODUCTION use ended. So, the "I-beam" shafts were still being manufactured at least right to the end of C3 PRODUCTION. Whether they were used in C3 PRODUCTION would be interesting to find out."
Joe,
"I beam" type on both sides lower a-arms on my 1980. (Both upper a-arms are "solid bar" type.
DaveJudging Chairman Mid-Way USA (Kansas) ChapterComment
-
Re: 63 Lower A Arms - Which Shaft is Correct?
Dave-----
Thanks. Very interesting.
The upper a-arm shafts were always "solid beam". At least, I've never seen one that was otherwise.
By the way, the upper a-arm shaft was not the same as 58-64 passenger car. It was the same as 1965-70 full size passenger car.In Appreciation of John HinckleyComment
-
Re: 63 Lower A Arms - Which Shaft is Correct?
Joe,
Regarding your belief that the I bean configuration was the original used on 1958 cars I think I have just come across a third version and early version of 3738505. Yesterday I obtained a pair of lower A arms out of a 1958 Chev passenger car that a local person is using as a parts car. The numbers are a little difficult to read but I make them out to be 3738505. They are still in the A arms so I have not been able to do accurate measurements yet but for all intents and purposes they look to be correct. The only difference I can see is that the shafts are round, not the solid rectangular or I beam. I wonder how many more are out there.
Norm
P1110639.jpg P1110641.jpgGolf is for those who can't play hockey.Comment
-
Re: 63 Lower A Arms - Which Shaft is Correct?
Norm------
Yes, I had forgotten about the round shafts. They were the first design. While they would work on a 1963-82 Corvette, they were never originally used on any such Corvette, at least as far as I know.
It's extremely interesting to me that through the 3 design changes the forging number for this shaft was never changed.In Appreciation of John HinckleyComment
-
Re: 63 Lower A Arms - Which Shaft is Correct?
Norm, I have a 1965 Coupe. My shafts are just like yours. Different on each side. That said, I don't know for sure if they are original but believe them to be. Thanks for posting. I was wondering about this.
TerryComment
-
Re: 63 Lower A Arms - Which Shaft is Correct?
Joe,
Mine look just like the very first photo in Norm's post. They are both different from one another.Comment
Comment