How to check the rear stub axle for weakness?

[jbcollier]

You should check the shimming of the half-shafts at the same time.

[SwiftDB4]

And also ANY play between the hub carrier and the bearings.

[EuropaTC]

Personally I have never undone the locking washer and checked the torque on the rear driveshaft nut although I would agree that it sounds as if you should from the wording in the manual and the reference to checking other torque figures.

When I ran the Europa daily I'd have a monthly "Sunday morning session" where I'd look over it, check oil levels and lubricate the trunnions/rear UJs. For the rear hubs I'd just check for play and smooth rotation, heaving on the wheel usually shows up wear before it gets serious. Out of interest my worst ever bearing was showing wear at 4,000 miles although I think there was something wrong, either me when replacing the bearing, buying the wrong specification or maybe just cheap rubbish.

Brian

[Nockenwelle]

Very valuable comments here, highly appreciated

I think the reason for the thread failure could indeed be to drive the car with a non-properly torqued stub axle. If the hub is not properly seated on the axle there is an increased bending moment with every revolution of the wheel. As our cars have seen a long time of usage you just don't know the 'stress history' of the part. I will carefully check the part but tend to just buy two new stub axles to be on the safe side.

[jbcollier]

The stub axle assembly was lifted from a low-HP car.  The reason they break is a lack of a proper radius and, mainly, because it is made of cheese.

[Certified Lotus]

Not good news for my 150HP TC in my Europa..........

[BDA]

I wonder if having a twin link rear suspension helps the stub axle since the stub axle is no longer part of the suspension (if you get my drift). That should relieve it of the tension and compression normally transmitted to the tranny. On the other hand, the failures don't appear to be related to tension or compression - unless you consider failures from squashing the stock bearing spacer as a cause for failure but then hardened spacers would be the solution for that. Just thinking out loud...

JB, I noticed that you posted a picture of an alternate stub axle arrangement. You've probably already posted about it but could you tell us a little about it here?

[jbcollier]

The stub axle was brilliant but the machining of the splines in the yoke were off.  I have it at a machine shop right now to correct it (hopefully).

[BDA]

Was it of your own design or did you purchase it somewhere?

[jbcollier]

It was this chap:

http://www.dogrings.com/products.html

He used to offer replacements for the Imp axle set up as used in many 60s single seaters.  Not sure he does any more.

[Grumblebuns]

Wayne Mitchell is the owner of Dogrings and lives about an hour away. He has a varied background in engineering, formula race car driver and now a machinist working out of his garage. I have commissioned him to to design and fabricate an updated Europa hub and stub axle. Stay tuned for updates.

If anyone has a need for rear type 47 magnesium uprights, Wayne has a couple of sets left over from his run about 10 years ago. They are a beautiful piece of work 

[BDA]

I was looking though some files and found this design for half-shaft/stub axle/disk brake. I found it on lotus-europa.com. It's an apparently old contribution but it was anonymous. The half-shaft part looks a lot like what Richard is selling. It's not complete as somethings are not designated like materials, splines, or suppliers of bought parts (I think there is one or two), but I thought it might be useful to someone as a starting point.

edit: I originally said I didn't know where it came from but I finally found it on lotus-europa.com.