Half shaft u-joint flange , 63

[Steve D.]

While installing new universal joints, I noticed that the two half-shaft u-joint flanges were not identical. On one, the top inner part of the yokes are beveled, just like on the half shafts. On the other one, there is no beveling.
I'm assuming that the one without the beveling is aftermarket? Or did some of the later years not have the bevel?

The joints (Neapco)that I have will not fit into the one without the beveling. (ie, with the bearing caps removed, the trunion cannot be maneuvered into the flange.) I checked the old joints that had been removed, and they had a slightly smaller shoulder, and can just slip into the unbeveled flange.

I guess I have two choices; a) find one new joint that will fit into the unbeveled flange, or b) find a new flange that is beveled. If I order a new flange, is there anything to specify, other than asking the order taker to check to make sure that the yokes are beveled?

Steve

[Joe L.]

Re: Half shaft u-joint flange , 63

Steve-----

From your description I can't tell which flanges that you have. However, I can tell you this much: 1963 Corvettes used unique-to-1963 half shaft u-joint flanges. This flange, GM #3832048, was considerably thicker in cross section than later flanges. That's because this flange is machined from a nodular iron CASTING. Its configuration is considerably differerent from and it's EASILY discerned from the later flanges. Most folks don't care about this CONFIGURATION difference, though; they're more concerned with "numbers" and "dates" on shock absorbers, alternators, carburetors, etc.

For 1964-1974 flange GM #3840318 was used. This flange is thinner in cross section, but much stronger since it's manufactured from a FORGING. It became the SERVICE unit for 1963 Corvettes when the above-referenced piece was discontinued in March, 1966.

From 1975-1979, flange GM #360912 was used. This piece is also a forged steel piece, but somewhat different in configuration than the above-referenced. It is manufactured by Spicer and all examples of it that I've seen, whether sourced through GM Parts under the above part number or sourced through Spicer dealers under their part number, have the word "Spicer" embossed on them. This part replaced the above-referenced parts for SERVICE of all 1963-74 Corvettes when the 3840318 was discontinued in August, 1975. It's still available to this very day.

ALL of the above-referenced pieces should be FUNCTIONALLY interchangeable.

[Joe R.]

Re: Half shaft u-joint flange , 63

Steve,

It sounds to me like you have a problem. With your description I believe you have one (1) original flange from a 63 and the rest is later model stuff. If you are going to have the 63 judged you are going to loose a lot of points for wrong half shafts (2) and one later flange.

I could be wrong but from the description the one flange you describe is a 63. The one that is not beveled and looks pretty rough. That is probably a 63 flange. When you take it off where it bolts to the spindle flange does the circle make a complete 360 or is it indented on two sides.

Could you send some pics of what you have? Then I or someone else on the board can help you in more detail.

Regards,

JR

[Duke W.]

The other problem with...

the original '63 half-shaft end flange is that the half shaft yoke will ground out on the flange at full rebound. This is not likely to happen in service unless your get your car airborne, or near airborne, but I consider it to be a design error and potential safety defect and recommend replacing the '63 unique half shaft flanges with the current third design part.

There's some anecdotal evidence that the second design part that Joe mentioned also causes grounding, but the third design and currently available half shaft end flange should not.

The '63 end flanges can be recognized in judging, and not having the correct examples will cost you some points, but I still recommend '63 owners replace them with the latest design when you rebuild your half shafts with new u-joints.

Something else I can tell you is that it's easy to bend the cast end flange and have a stiff u-joint, which will probably fail early. The current part is much stiffer and stonger, and will not be as likely to suffer any damage installing new u-joints.

Duke

[Joe L.]

Re: Half shaft u-joint flange , 63

JR------

The 63-74 half shafts were, basically, all the same configuration and size. The only difference was that 65-74 big block versions were shot-peened. So, as long as the half-shafts are the 2-1/4" OD, I think they should be alright. However, if the car happens to have one or more of the 3" OD half shafts which were used in PRODUCTION from 1975 onward and which SERVICE all 63-74, then a change to a correct shaft would be advisable for judging considerations.

[Joe L.]

Re: The other problem with...

Duke----

Even the GM #360912 piece can be damaged (i.e. bent) when removing and/or installing new u-joints UNLESS a special fixture is used to support the flange during the removal/installation process. An old spindle flange, bolted to the u-joint flange, can serve as such a fixture. With the fixture installed, there is little damge of damaging the u-joint flange. However, I always recommend that folks have this work done by a driveline shop. The half-shaft u-joints can be a "bear" to remove and get installed properly. There's no substitute for experience on this one and, usually, the cost is nominal.

[Joe R.]

Re: Half shaft u-joint flange , 63

Joe,

I agree that basically all half shafts are functionally OK to use, however when put side by side the 63-64 half shafts have a lot more of a casting to deal with on each end. I have the 63-64 here on the floor along with the later 65-74. The later is much cleaner and probably stronger.

I can see a 63 making a lot of noise if the suspension drops. (Like when it's in the air)

If this guy wants a correct 63 for judging purposes he will have to find the correct stuff. If he wants a driver I also would recommend the later parts since it is stronger and less likely to cause problems.

Nuff said,

JR

[Steve D.]

Thanks for the input

I checked for a number on the unbeveled flange and found 3832048, making it a 63 flange. I am not going to have the car judged, but am trying to get it mecanically sound for driving.

Thanks for all of the input.

Steve