Driveshaft-Diff Uni Failure

[Dinsy]

Hey guys,

I've recently had a bit of an issue with the universal joint between the driveshaft & diff, originally I thought that I'd sheared one of the pins (while it was still in the car, just looking at the amount of movement it had and the damage to the joint), but now that it's out I'm thinking more along the lines of one of the pins pulling out of it's housing.

 

I'm going to get a new driveshaft & uni assembly made (From what I understand it isn't possible to replace just the uni as it is welded to the driveshaft). I've been recommended a local guy who is supposed to do very good work at a pretty good price.

 

Main problem is that I still don't really know what caused it to fail. . . . At the moment I'm thinking that some dust/grit may have gotten into one of the bearings causing that to fail and not give the uni propper free movement, that or too much torque going through the uni for what it was designed (More what I was thinking when I thought that the pin had sheared rather than pulling out of its' housing).

 

I'm wondering whether anyone has had this happen to them, or has an idea what have have caused it?

I've attached a couple of pictures that hopefully show it properly.

 

[Zedman240®]

I'm guessing sometime in the past, when the uni had to be replaced someone may have not known how to remove it properly and bashed it with a large hammer and cracked it? Does the break look clean or rusty and old? It may have been cracked for years and finally let go.

[reverendzed]

I can guarantee that it was all good when I had it.  The tailshaft had actually been inspected when all the engine work was done.

Rev.

[Enzo]

Hi,

  It's unfortunate that you have a problem of this sort, but you have to bare in mind that we all drive 35 year old cars and any parts that have not been replaced with new can be prone to metal fatigue or wear. Luckily it didn't come apart when you had your foot to the floor in fifth gear.

David.

[620Z]

Play it safe and upgrade to a 1310 uni when getting a new one made up. Then when if you upgrade your power you don't have to worry about the drive line.

My philosophy is to upgrade when replacing. Since you already have a nice car. Don't muck around putting the same back in.

[Scando]

The uni should be able to be removed from the driveshaft.  The uni joints are pressed in not welded in.  I just run Hardie Spicer heavy duty uni joints in the standard driveshaft.  With a naturally aspirated L series this should be plenty strong enough.

[mayhem]

The uni should be able to be removed from the driveshaft.  The uni joints are pressed in not welded in.  I just run Hardie Spicer heavy duty uni joints in the standard driveshaft.  With a naturally aspirated L series this should be plenty strong enough.

hes rite they never weld uni's at all you cant cause they are bearings..

if you want a guy ive got the guy .. i had to get ones suited to over 400hp and its cheap trust me i will beat anyones price!!

[.]

hes rite they never weld uni's at all you cant cause they are bearings..

if you want a guy ive got the guy .. i had to get ones suited to over 400hp and its cheap trust me i will beat anyones price!!

 

Those statements are generally correct but you can't account for idiots. Someone might have welded this one....that may be why it let go in the first place.

[mayhem]

tru ive seen worse

[Dinsy]

Cheers for all of the feedback,

 

I'm guessing sometime in the past, when the uni had to be replaced someone may have not known how to remove it properly and bashed it with a large hammer and cracked it? Does the break look clean or rusty and old? It may have been cracked for years and finally let go.

It definitely looks like a pretty fresh break, everything in there is either nicely painted or freshly exposed metal. I've had a pretty good look and nothing stands out as a prior failure.

 

Hi,

  It's unfortunate that you have a problem of this sort, but you have to bare in mind that we all drive 35 year old cars and any parts that have not been replaced with new can be prone to metal fatigue or wear. Luckily it didn't come apart when you had your foot to the floor in fifth gear.

David.

Yep, part of my thinking behind getting an older car was that issues like this would occasionally surface, as much as I'd prefer it not to happen, I actually don't mind because I find it interesting having a propper look at things that I wouldn't normall take out just for the hell of it. And yes it was some pretty lucky timing, I was about 10 mins away from highway in 5th gear, would have been a pretty nasty surprise for anyone following me if the tailshaft dropped out the back at 110km/h.

 

As for the welding .... it definitely looks welded to me as it is slightly raised over the diameter of the shaft & uni, and there are a couple of very small imperfections in it. When it actually failed I took it straight to a local CV specialist who flat-out said there was nothing he could do as the uni wasn't removable from the tailshaft, I took that at face value as he didn't try to sell my anything else and wasn't busy at all so I doubt he was just passing on the cheaper jobs. That said, it has been painted over so I can't see any slight edge that I'm assuming would be there if it had been pressed in.

 

Also, I don't want this to in any way look like I think Rev. has done a dodgy, as everything in this car has been absolutely fantastic.

[Scando]

The four caps as I have marked with the red cross press out of the eyes in the yoke.  However now I've looked at the picture closer it looks like the yoke is cracked where i have marked with the green cross?