SC drive shafts - fitting query

[Dieter H. Marschall]

Glenn,
This is what I bought from Goodparts in the USA, a very similar solution: https://www.goodparts.com/shop/index.php?productID=835
Best wishes,
Dieter.

[Motorsport Micky]

Tim,

The more I've reread these posts the more important it becomes to me that these CV shafts should only be used through their operating range, and that operating range is controlled by the rear shock absorbers.
After CV shaft fitment I would definitely avoid removing the shock absorbers and jacking the rear end up allowing the trailing arms full unrestrained droop therebye possibly overextending the CV past their maximum fitted length. If shock absorbers are to be undone I would definitely unbolt the CV driveshaft from the diff saving any possible problems before the shock absorbers are undone and the trailing arm reaches full unrestrained droop.

Micky

[Tim Murray]

Micky, you are 100% correct. And it was doing precisely what you have deduced, that allowed the shaft to exit the joint. I had estimated that I had enough extension to get away with it, but I was wrong. It strikes me that, if the suspension was ever to bottom out, the amount of shaft left engaged with the joint would be very small and the risk of damage would be very high. So careful approaches to hump back bridges, and large pot holes. It would be so helpful if SC Parts and/or Limora would just tell us what the max operating length actually is
Tim

[Tim Murray]

To Dieter and Glenn: I think this issue of the gap between the hub and the brake back plate is misleading. [ or perhaps - its just that I can't make any sense of the instruction ]. The point is this, once the shaft is in situ, and the shaft is as near to horizontal as possible, the hub can then be drawn outward:- until the shaft falls out of the CV joint. There is nothing to stop it. So the gap can be any distance you want, up to the moment it separates. But hey ! perhaps that is the point of the instruction. As long as you can get that gap without it falling apart then you are sound. I don't actually believe that can be true, because the amount of engagement between shaft and CV joint could be minute. I remain confused.

[Motorsport Micky]

Tim,

I don't think that the compression caused by large bumps or humps will cause a problem with the CV shafts, this is a parameter the CV suppliers can expect and doubtless will have tested. However the removal of the restraining influence of the shock absorbers will allow unfettered expansion of the CV shafts when exposed to full droop conditions of the trailing arms when lifted on a ramp or jacked up, not a condition the suppliers will have taken account of, why should they ? it is not expected to occur.
This full downward expansion is fairly unlikely to happen on the roads because

a) It is controlled by the fitted shock absorbers, and
b) To achieve even the full expansion of the shock absorbers requires the car to travel over unfeasibly deep potholes or be driven in a manner more befitting "Daisy Dukes" relatives !

To return to my response in post #2 if required we can accommodate any increased range of movement required by the shaft by the addition of shims to increase the "stored" free length left in the CV shafts, and handle any transient hyperextensions. However now having examined the circumstances which have occurred with these shafts and talked it through with yourself and the other respondents here I'm of the opinion that we've nailed the reason of disassembly of these shafts which can be avoided by using them within their operating parameters.

Micky