Broken Drive shaft

[zcacogp]

Will,

Thanks for the update. For what it's worth, my initial comment was that it wasn't a broken drive shaft, so don't go saying that I am right all the time!

That's an interesting bit of fracture you have there. (And a lucky escape - if that had gone at any speed ... well, 'nuff said.) Yes, it looks like there was a large crack which absorbed water and grot over a period of time, and finally the rest of the shaft gave up. The last pictures aren't quite clear enough to see the beech marks in the break, but that's not important - the reason for failure is very clear.

Well done on the fitting. In answer to your earlier question, I bought 4 CV joints with bolts from Max at Frazerpart, who was excellent (0151 644 6433) and it came to £194. Fitting them was between 2 and 3 hours.

If you bought a replacement driveshaft with CV's, I'd be tempted to keep the CV's from the old one (particularly if they are fairly new) on a shelf as spares - they will fit on either end of the driveshaft and can be used when any of your current ones wear out.


Oli.

 

[Guest]

Thanks for putting up the photos Will.

From the lower photo it looks as though the problem may well have started in the groove where the end of the boot sits. Possible scenario is corrosion pitting in this groove ( I have a spare 924 shaft which I looked at this morning and it is quite badly pitted in the groove ....) provided the starting point/stress raiser. The groove itself starts life as smooth and well-rounded but nevertheless it is the weak point of the shaft. Whithout it, then the weak point would be the inner-end of the splines.
What is certain is that the rusted area is where there was slow growth of the crack over a long period and the bright area is the sudden final failure.

Certainly when I next have the shafts off I will be cleaning this area back to bright metal, examining very carefully and then if all is well, red oxide primer and a good topcoat of paint. If I have the CV's off at both ends then I favour putting the shaft in the lathe and cleaning all the corrosion off with emery cloth.