The wheels on the Europa go round and round

[jbcollier]

When I overhauled my S1’s rear suspension, I refitted the stock uprights, spindles, hubs and bearings using loctite 635 on the splines and hardened spacers.  At the time I noted that the bearings were not very tight in their bores (almost a throw fit) so I sent out a spare set of uprights and had them fitted with steel sleeves.  Shortly thereafter I tracked down a replacement set-up meant for an Imp:

https://jbcollier.smugmug.com/Lotus-Europa/i-cQpwGW8/A

https://jbcollier.smugmug.com/Lotus-Europa/i-qpK59M9/A

(more accurately, 60’s single seaters using Imp rear hubs and spindles)

It’s a clever design that essentially eliminates the possibility of being passed by your own rear wheel.  I particularly like how the yoke, and thus the half-shaft, can be easily removed.  Albeit you are still using loctite so some heat may be involved.  The kit was (still is?) made by Wayne Mitchell.  His website is:

http://www.dogrings.com

though the Imp kit is not listed, never was.  You have to ask.

Last year, at about 5K on the clock, I found a loose wheel after a drive of 2K.  So I decided it was time to put plan B into action.  First I carefully checked over Wayne’s parts.  Unfortunately the splines were not machined correctly, try an interference fit of over 10 thou!  On a proper jig, splines are easily and quickly machined.  From scratch, and with no measurements, it is a whole new kettle-of-fish.  Took a while but I found a large industrial shop willing to do the work.  It was very, very not-cheap to the tune of $1K.  Still, it made good what would otherwise have been so much scrap.  I’m happy.

I know you are wondering why I just didn’t get Wayne to sort it.  Well, it was not easy getting the kit in the first place.  Wayne was very confused and repetitive.  I got the distinct impression that he was in decline.  Better a stupidly expensive kit in the hand that a free-fix never seen again.  YMMV.

Fitting was not straight forward.  The stock Imp’s splines are long.  Using a spacer to make room for the brake drum is no big deal.  On this set-up, the splines are relatively short so spacing the drum 6.5mm (the actual difference between the two) is a concern.  I decided to have no spacer between the spindle and the outer bearing and to instead space the drum off the spindle/hub.

Spindle/axle fully home and just missing the wheel cylinder:

https://jbcollier.smugmug.com/Lotus-Europa/i-vmpQMhV/A

6.5mm spacer:

https://jbcollier.smugmug.com/Lotus-Europa/i-gpHPwFn/A

https://jbcollier.smugmug.com/Lotus-Europa/i-QvMbRDb/A

https://jbcollier.smugmug.com/Lotus-Europa/i-28LHVBt/A

https://jbcollier.smugmug.com/Lotus-Europa/i-8BV6rTK/A

Wheel studs, lamalloy L9 cap screws, tack welded in place and then ground to clear the brake shoe springs:

https://jbcollier.smugmug.com/Lotus-Europa/i-5kBQ5FZ/A

https://jbcollier.smugmug.com/Lotus-Europa/i-hfVghv6/A

Here’s the resulting spline protrusion

https://jbcollier.smugmug.com/Lotus-Europa/i-2J7TTw4/A

(You can see why I didn’t want to lose 6.5mm)

And the yoke slipped into place:

https://jbcollier.smugmug.com/Lotus-Europa/i-P485VWq/A

Secured:

https://jbcollier.smugmug.com/Lotus-Europa/i-M9cVFCs/A

The last modification was to trim the sides of the retaining nut to increase amount of travel in the one plane:

https://jbcollier.smugmug.com/Lotus-Europa/i-6h2bdVz/A

(SKF joints with an easy accessible grease nipple)

And, finally, all bolted together:

https://jbcollier.smugmug.com/Lotus-Europa/i-LPGR4w5/A

(Yes, I saw the loose upright bolt)

I’m delighted with the results.  Yes the wheels still go round but now women are irresistibly attracted to me… well, actually, just the wheels go round but the extra peace of mind was well worth all the effort.

Would I do it again?  No.  I would buy this kit instead:

https://kelvedonlotus.co.uk/product/race-drive-shaft-kit/

It is actually designed for a Europa and you’re not trying to fit something actually designed for an Imp.  Though, that said, I do think Wayne’s way of securing the yoke is particularly brilliant.

[Rosco5000]

Thanks for the write up John.  Looks like it worked well in the end.  The Kelvedon piece looks nice too all be it pricey.    Could the securing bolt be extended on yours and lock wired to the universal joint ear?

[BDA]

Thanks for the very nice write-up, JB! The Kelvedon kit looks nice. I wonder if you considered Richard's axle kit? They both look similar. Do you know how much Richard gets for his?

[jbcollier]

If you look at the first photo, the hexagonal retaining nut fits into a hexagonal recess milled into the yoke.  No need for lock wire there.  The allen bolt fits into a machined recess in the spindle/hub.  It's not possible to use lock wire there either.  You could pin it, I suppose.  The allen bolt is tightened to 60 ft lbs and has lots and lots of engaged thread so I am not worried about it coming loose.  I will monitor it weekly for the first year and see how it goes.

Richard's kit, and the one often on ebay, involve welding a old yoke to the revised axle.  I know of one that failed.  Beyond that I have no experience with those kits.

[jbcollier]

Correction:  I hadn't looked at the Banks set up for a while.  It's the same as the Kelvedon kit.  I suspect Kelvedon is just selling the Banks kit.

[BDA]

If anyone is interested in upgrading their axles, a call to Richard would be advised - first to compare prices with Kelvedon but also for details. Taking another look at Richard's pictures, it's not clear how the u-joint yoke is attached to the axle. The Kelvedon kit axle is clearly threaded and a nut is provided. The Kelvedon kit also includes a bearing spacer which is nice.

[jbcollier]

Just an update.  I’m half way through a 2000 kilometre road trip and I brought a torque wrench to check the rear axle yoke retaining bolts as I went along.  First section was 350 kilometres and was the first time I checked the Allen bolts after the install.  They both tightened up slightly, about a 1/16th of a turn.  I then drove 400 klicks and checked again.  Nothing this time.  Another 350 klicks and nothing again.  I think everything is settled now and that is the last time I’ll check it between services.

[lotusfanatic]

Hello JB!

I'm pleased to read that your rear wheels haven't passed you on your journey... 

(please do post any pics of your journey!)

Mark

[Grumblebuns]

I got a chance to stop by and speak with Wayne Mitchell a week ago at his shop to discuss the rear stub axle kit that John Collier had problems with. Yep, John is correct; Wayne does not understand what the problem is. John, can you give a more detailed explanation on the spline issue with photos if possible. I plan on stopping by again at Wayne's shop at the end of July in order to bring Wayne a complete TCS rear suspension for him to use as reference and order the rear stub axle kit that John used. I'll make sure that his version 2 will fit correctly on the Europa upright. In Wayne's defense, he is 79 yo but don't feel that he's mentally impaired in any sense speaking with him several times.

Joji Tokumoto
Fallbrook, Ca

[jbcollier]

Hi Joji,  There were two problems with the kit, one a flaw and the other because of the adaptations Lotus made.  Starting with the latter, Lotus added a spacer on the drum side of the axle to correctly position the brake drum in relation to the backing plate.  This spacer adds roughly 6.5mm over what the Imp required.  On the stock set-up, the spline contact is long and the loss of 6.5mm of overlap no big deal.  With Wayne’s set up, spline contact is much shorter and the loss of 6.5mm is a big deal.  I used no spacer  between Wayne’s set up and the outer bearing and made a custom spacer to move the drum out from the axle face instead.

The solution would be to lengthen the supplied axle and special “stress-reliving” spacer to suit the Europa application.  No complaints there.  It is what it is.

The former issue was that the splines cut into the yoke were done incorrectly and poorly.  The “interference fit” was so tight that it was shaving quite large chunks of metal off, and it wouldn’t fit together even on a press — perhaps it would have gone had I max-ed the press but that would have made for unhappy parts (and owner).  I had to have the splines “tweaked” on the yokes to suit.

This all would have been easy-peasy on a jig but quite another matter working from scratch.  It was very expensive.  I’m not unhappy though.  I now press hard into corners with absolutely no trepidation — priceless as they say in credit card speak.

[Grumblebuns]

John, I think I understand the two issues. When I stop by his shop in a few weeks, I'll bring over a fully assembled stock rear upright (TCS and S2) for Wayne to use as a reference to ensure that all of the pieces fit the way they are suppose to. I'll be using the same setup that you have with all of the issues resolved (hopefully) so I'm interested in your feedback.
 
Looking at your photos it appears that the need for the inner spacer is eliminated with the use of the cone spacer behind the wheel hub and the central bolt that goes through the hub, stub axle and yoke and locks the whole assembly in place. So far from the mileage you've put on, no loose axles.

Joji Tokumoto
Fallbrook, Ca