Outboard Drive shaft S2 left hand thread?

[S2Zetec54]

Hi All

Car slightly pulling when braking so checked the vehicle and found the hub on the outboard shaft, near side in a UK right hand drive car...ie the left looking from the rear, loose...further investigation revealed a rounded off D washer (sorry don't know the proper name)

Anyway, using loctite 660 (635 too expensive) to lock/fill the splines properly and then torque it up properly. We'll see how it works and if that doesn’t I'll have another go with 635 etc....Good learning experience to be honest

My question, and I have searched, is can one buy left hand threaded outboard shafts to stop this propensity to undo?

Would this be the answer? Prob very expensive even with a group buy

[BDA]

I’ve never heard of one but there are alternate ways of locking that nut. My machinist drilled an axial hole at the threads of the nut and the outboard shaft, tapped it and screwed and loctited a set screw or grub screw in it. It seems I’ve heard of other locking methods but I’m drawing a blank at the moment.

[SwiftDB4]

In 50 years of Europa ownership I've never had the nut loosen, but others obviously have.  Usually the outboard shaft bearing journal pounds out and play develops there. Lotus should have used hardened steel and the journal needed to cover all of the bearing width, not half. At least they could have improved the original Imp design. Failures occur on the RR also so I'm not sure the thread direction is much of a factor. Best redesign seems to be the solid hub and shaft with the u joint bolted inboard of the housing.

[jbcollier]

D washer = lock tab washer

The most common way they loosen is the collapse of the mild-steel, inner spacer.  Another is when they weren't tightened properly.  You can't just tighten the nut.  You need to tighten the nut, drive and corner it hard, tighten the nut, driven corner it hard, and keep repeating until it's stable.  Then bend the lock-tabs.

This is why you use 635.  It is a slow setting compound and gives you time to assemble and go through the tightening process before it sets.

[gideon]

In answer to your question about the axles, I believe the answer is yes.  Here's the link

http://www.pamotorsport.com/for_sale/index.php?option=com_virtuemart&view=productdetails&virtuemart_product_id=279&virtuemart_category_id=36&Itemid=109

If you haven't yet read the analysis by Richard H on this problem, then do read it before you do anything else about this

https://groups.io/g/LotusEuropa/files/Stress%20analysis%20of%20Europa%20rear%20axle.pdf

[S2Zetec54]

Thank you everyone those are incredibly useful answers and links.

BDA, the drilling through and or use of a castlegated  is a useful idea and I will keep up my sleeve. As you have done I would leave in the hands of a machinist if I go down this route

JB thank you. I had read previous posts by you on this and I am embarrassed to say I am trying 660 first despite your sensible advice about 635 and the proper tightening technique before finally deploying the lock tab washer. She's loosened before on the RLeft but this is the first time that any sort of glue has been used....so there maybe damage that will mean my efforts are in vain anyway. If she fails again I will use new parts and your technique along with 635

Gideon that is a great link...I am excited to call them to discover the price. I will post a price once I have. I am afraid your link to RichardH's  analysis does seem to let me see anything....I'll do a RH search on this forum and see if anything comes up.

Thank you all. I'll let you know how my current attempt has gone.

[gideon]

I reckon that Richard's analysis is the most important thing for you to read.  You should join the groups.io mailing list to get access to the files stored there anyway.  It was too big to include as a single file here, but I was able to split it into separate pages.  Maybe that'll work.

[BDA]

If you haven't yet read the analysis by Richard H on this problem, then do read it before you do anything else about this

https://groups.io/g/LotusEuropa/files/Stress%20analysis%20of%20Europa%20rear%20axle.pdf

I have seen that analysis before but never took the time to read it but your suggestion prodded me to finally read it. Very interesting. While I certainly don’t dispute his analysis, I have always understood that changes in the TC/TCS improved the situation (rather than make it worse). I certainly haven’t done a study on TC stub axle or bearing failure like the author did so I could be ignorant of the situation but I have heard of very few failures on TCS. Maybe somebody can update me.

Our own andy harwood started investigating using VW stub axles and CV joints. The stub axles are hardened and there is large assortment of axle lengths. It seems like a very good “final” solution that doesn’t seem to require a whole lot of development.

[SwiftDB4]

Thanks for the PA Motorsports Europa axle page. Look very interesting in that they're better steel and outer bearing journal is as wide as the bearing because they shortened the spline section.
 Wonder if the inner journal is 30mm? Wrote off to get more info.

[S2Zetec54]

Hi All just had a very nice conversation with Peter at PA Motorsport. He uses these for his single seaters. He knows they fit series 1 Europas but is unsure of later versions. I think he said they were Imp outboard driveshaft. So do the series 1's fit series 2's.? They are 295 for each one and 24 for each nut....didn't ask if that was plus vat taxes etc...that's £

I said i would send him any engineering drawings I could get my hands on to show the series 2 dimensions etc...i'll go digging when I get home unless someone has a pdf of these dimensions we could rely on.

[SwiftDB4]

S1 and S2 axles are the same.

[jbcollier]

S1 and S2 take the same rear stub-axle.

That PA axle looks to be the perfect, bolt-on fix.  Combined with hardened spacers and you should be good.

[S2Zetec54]

Thank you JB and Swifty thats excellent news. I have just read R Hills article kindly downloaded by Gideon, terrific article which is fascinating and really useful...well worth a read thanks to Gideon.

Hopefully what I have just done will buy me a little time while I accumulate the parts and do both sides using all the recommendations plus the inner bearing recommendations in the Hill Analysis.

Cheers everyone

[jbcollier]

OK, forgot to mention another source of "hub nut loosening".  That is a soft lock-tab washers.  Most of the washer you can get are "soft" steel so you can fold it over.  Well, soft works both ways and it can "thin" out under pressure "loosening" the hub.  A proper lock tab washer will be hardened steel with a foldable tab spot welded to it.

[S2Zetec54]

Thanks JB...good point. I guess I have to go to a machinist/engineer and specify how I would like these components and their hardness ?.....I'll do a search and see if there's anything off the shelf on the web somewhere....we're quite lucky locally and have a few engineers around with good reputations

Cheers