I have been repairing Corvettes for a very long time and I know I have not seen it all..and this just proves it again.

I have seen broken U-joints and the eyelets in the half shafts wear and break...but NOT this. This is a new one.













I am sorry if these photos are not crystal clear. I never claim to be a professional photographer. BUT..I can say that the tube literally appears to have peeled off and it peeled right back from the weld.....so the end of the surface of the tube is smooth.

The owner who sent me the car for repairs told me that he as pulling out onto the road and driving normally ( no crazy stuff) and when at about 45 MPH and it changing into possibly third gear....due to being an automatic...the half shaft did what you can see.

This is a 2-1/2" diameter half shaft on a 1969 Corvette.

Not that I do not inspect parts very well...but I now know I have to look at his area when I am working on replacing U-joints or whatever. I know this seems to be a rare case ( at least for me because this is the FIRST ONE)...BUT...for me...all I have to see it happen one time and then that adds another visual inspection I feel I need to do to make sure parts are correct.

DUB

 

Crazy!!

 

That tubing looks to be welded seam tubing, I sure didn't think that this type of tubing was used for drive shafts. Does the owner know if that shaft has been repaired or is it the original?

Hard to see but if looked at soon enough after failure you possibly could have been able to tell if the weld cracked over time.

odd type of failure,

Neal

 

Original half shaft...or all indications is that it an original. YES..it was a welded seam tubing..I looked down inside it and can see it..

DUB

 

Thanks for sharing this. And correct about one more thng to look at while under the car. Maybe even a good reason to keep things relatively clean so that a potential crack might show up before things self destruct.

 

I think that might be exactly what happens when Bubba puts a 750 hp blown mill in his [otherwise stock] early C3 SB car, sticks really gummy BIG drag slicks on the rear and stabs it for all it's worth from a dead start.

It might just break the weld on the outer flange and peel the tube apart like an onion. Driver must have shut it down pretty quickly...not much other damage on that half-shaft tube.

 

DUB,
Never thought that could happen. Also suprised it the tube has a welded seam.
When I was in my teens and power shifting (still do it) a old timer said that a kid broke his driveshaft at the trans and when the front of the shaft hit the pavement it broke away from the rear end and came up thru the back seat of the car. I think he said it killed one of the passengers.

Dom

 

I think the word of the day is 'FATIGUE'.

The car was picked up today by the owner and when I was pulling it out of the shop...even though it was an automatic...when it was put in gear...it engaged rather stoutly due to the RPM's where slightly up.

I HONESTLY feel that I will never see this type of failure again in my career from a street driven car.

DUB

 

I don't know, DUB. That's a weird one.

 

My theory, based on experiences many years ago, is that someone used a BFH to change the original u-joints and compromised the welds - after that, a good hard takeoff can rip the tubing off the flange.

 

Good theory...so you have had actual experiences with the half shafts that look like this???

But the tube on the other end is not dented and no noticeable signs of being beaten to death for U-joint removal/installation.

What I have tried to analyze and see in my mind is that even IF one inch of the tube had a cut or break in the weld..HOW in the heck did the REST of the tube ALLOW the cut to increase when there is STILL so much area still attached. There is nothing around it to grab onto and use it like a can opener.

DUB