mid-life crisis needs a mid engine car

[BDA]

There's nothing wrong with the rear suspension. The rear bearings for the S1 and S2 are marginal but I haven't heard of any real problems with the half shaft as upper control arm. It was used on all Europas. I should say that I have the twin link rear suspension you mentioned so if there is a weakness, I could have easily missed it. Setting up the half shafts does require you to properly shim the u-joint yokes on the output shafts.

There are a couple of twin link designs. Banks' is the easiest to implement since it comes in a kit. I believe they all maintain the stock geometry and if not, they are very close to the original. The Banks kit replaces a u-joint with a CV joint. Any twin link design will require a new hall shaft since it now has to change length. This takes load off the tranny so theoretically, it should enhance its life. The Banks kit doesn't require you to take the body off to install.

[FROGUS]

Well I saw a video in which a French Europe's owner explains he broke two half shafts and read here and there that some people were overtaken by their own rear wheel...
I didn't realized that you have to purchase new shafts and fit CV joints along with the kit

May be I worry too much!  First step is to buy the car, drive and enjoy it and then think of improvements
I can't wait to see it

[BDA]

I have a hard time imagining what it would take to break a half shaft. The stub axles are another matter. They came off the Hillman Imp. They are not hardened. I have heard of some instances where the threaded part of the stub axle came off but I would not in any way say it is common. Having said that, I am looking into upgrading my half shafts, stub axles, etc. with VW parts. (One wonders why Lotus didn't start with them!) Our own Andy Harwood started down that road and explained some of it here (http://www.lotuseuropa.org/LotusForum/index.php?topic=2414.msg28915#msg28915). It requires some study but it seems like a good option. There are several.

[FROGUS]

May be he said half shaft but it's the UJ or yoke which broke

[BDA]

Like just about everything on an old car, U-joints are things that need to be lubricated and monitored and eventually replaced. Hopefully, the replacement happens before it brakes! 

[jbcollier]

The Banks twin link kit does not require new half-shafts.  You just don't fit the roll pin.  Movement of the inner yokes on the transaxle output shafts is minimal as the twin link pivots are located very, very close to the original pivot point.  I can dimly remember someone measuring how much movement there was and a few millimetres comes to mind.

[BDA]

Thanks for the clarification, JB. Mine came with new half shafts and a CV joint for each side. That may have been because I told Richard of other modifications I was making. I had also assumed that the splines were not appropriate for such sliding. Lastly, now that I think about it, since the geometry is very similar, if not virtually the same, there would be very little lateral half shaft movement. Obvious now that I think about it.

Keeping the stock half shafts is a nice thing for those who want to maintain originality as much as possible.

[jbcollier]

I went with the twin link because too much of my life was spent changing rear axle shaft u-joints in Triumph Spitfires.

[TurboFource]

JB,
Does your car have CV joints instead of the u-joints?

[jbcollier]

No, still have the stock joints.  They just don't have to take suspension loads anymore.

[TurboFource]

Wouldn't that also reduce the loads on the differential bearings?

[jbcollier]

The differential carrier bearings are huge and have no trouble taking the suspension loads.

The problem arises when the inner half-shaft yoke is not correctly shimmed.  The yoke bottoms on the diff output shaft.  Then the load first goes through the diff output shaft to the spider gears  and then to diff carrier and the diff carrier bearings.  The spider gears can't take the load and quickly fail.

There is nothing inherently wrong with the stock design as long as the shimming is correctly done.  Shimming should be check at EVERY service interval.

[FROGUS]

Interesting, how do you check it, jb?

Edit: I found a thread on the subject, try to understand it...