drive shaft Drive Shaft Scoring

[PeteW267]

Hi Guys,

Restoring my recently acquired GT6 mk3 (1973). 
When I disassembled the rear near side trunion and removed the drive shaft, it was missing one of the bearings that sits between the trunion housing and the drive shaft and there was significant scoring on the drive shaft (see attached photo). I suspect the bearing has broken up and disintegrated at some point previously.

My question is: based on the attached photos and info, is the driveshaft reusable/repairable or is it worth just buying a replacement. I suspect the other side will have the same problem.

The scoring is around where the bearings will sit between the drive shaft and the trunion housing, so it’s quite a critical location. The scores vary in depth, the deepest about 1mm.

If I need to replace, does anyone have any recommendations for suppliers?

Thanks.

 

[Gary Flinn]

I wouldn't advise reusing the shaft, they are a known weak point anyway and are prone to shearing around the bearing area.

TD Fitchetts at Telford supply reconditioned exchange Driveshafts but you may need to get a usable second one first to exchange.

Might be worth swapping them both whilst your at it for peace of mind?

Gary

 

 

[Pete Lewis]

ce re using the shaft , the needles dont take a lot of load and the general design is they keep the trunion/bearing housing parallel to the shaft so reducing any 

pitch and twist from the single ball race keeps everything nice and square /aligned.

fitting a new needle race to the pitted shaft will result in throwing the needles again 

also look at new  https://www.canleyclassics.com/triumph-gt6-mkiii-centre-assembly-mounting-details-outer-shafts-and-hub-fitted-from-ke/kf20001

there is a problem with shaft shearing if the os is fitted to n/s etc  as they have a torsional memory and end up with some  history wind up in their make up

reversing causes a shaft to unwind and a split developes followed by  a complete  and clean looking fracture .... be warned   seen a few failures all after fitting a unknown side shaft .

Pete

[JumpingFrog]

Be careful buying reproduction driveshafts, there's some poorly made ones where the UJ yoke detaches from the shaft after a few thousand miles. As I've had this happen, I can vouch for it not being a fun experience:

 

On sideways we've discussed this further, there appear to be at least two manufacturers, another manufacturer's driveshafts don't seem have this problem:

http://sideways-technologies.co.uk/forums/index.php?/topic/7973-spitfire-drive-shafts

I've told the suppliers about my problems, but never got much of a response or acknowledgement other than a refund.

[Colin Lindsay]

1 hour ago, Pete Lewis said:

there is a problem with shaft shearing if the os is fitted to n/s etc  as they have a torsional memory and end up with some  history wind up in their make up

After that happened to me (second time in twenty years, both on GT6 models!) I bought new as I couldn't risk another 50/50 'was-it-left-or-right-originally' used one, and when I had both halfshafts reconditioned for my Herald made sure each side stayed in the correct orientation. Having a wheel drop off is no fun!