Page 1 of 3

Rotoflex couplings

PostPosted: Tue Mar 27, 2012 6:16 pm
by ftsoft
Well, after 45 years it's finally time to replace my doughnuts. I have a fairly serious tear in the left outboard doughnut. I have read through the archives and am suitably intimidated, but determined to go ahead with it. There is mention of a coupling clamp to help the alignment of the holes. I wonder if this is worth tracking down or if just leaving the clamps on will suffice? Where would one find this clamp? Thanks.

Frank

Re: Rotoflex couplings

PostPosted: Tue Mar 27, 2012 7:13 pm
by nebogipfel
ftsoft wrote:Well, after 45 years it's finally time to replace my doughnuts. I have a fairly serious tear in the left outboard doughnut. I have read through the archives and am suitably intimidated, but determined to go ahead with it. There is mention of a coupling clamp to help the alignment of the holes. I wonder if this is worth tracking down or if just leaving the clamps on will suffice? Where would one find this clamp? Thanks.

Frank



Leaving the clamp on should be OK but if you want more flexibility the traditional method is linking good quality jubilee clips together to form a ring clamp of the appropriate size :wink:

Re: Rotoflex couplings

PostPosted: Tue Mar 27, 2012 8:11 pm
by pereirac
Frank,
New doughnuts come with a metal band fitted, only remove this after you have fitted the couplings. Jubliee clips joined together around the old doughnuts make removing them easier. I would use lots of WD40 as well as the bolts can rust into the doughnuts... If you have a Sprint, they have 'failsafe ' driveshafts to stop them flying around if the coupling breaks at speed. In this case you will probably have to disconnect the bottom of the A frame from the wheel hub to get the doughnuts out.

Re: Rotoflex couplings

PostPosted: Tue Mar 27, 2012 9:44 pm
by Fred Talmadge
45 Years! Mine are about 10 years old I've been thinking of replacing them. Maybe I got some bad rubber.

Re: Rotoflex couplings

PostPosted: Tue Mar 27, 2012 10:46 pm
by jimj
I found that new Rotoflexes only last a year or so and as failure doesn`t bear thinking about, they are quite expensive, and they are a pain to fit, I switched to Miller CVs. Fit and forget but to my mind the drive train is not as smooth. I never experienced the "kangarooing" with doughnuts in period, or recently, that I hear mentioned.
Jim

Re: Rotoflex couplings

PostPosted: Wed Mar 28, 2012 12:33 am
by Henry VIIII
You must have done relatively few miles if your doughnuts lasted 45 years.

I'm thinking of fitting Miller CV drives when my doughnuts next fail.

Billwill described the fitting process with photos at:
elan-f14/replacing-the-doughnuts-t16456.html

Re: Rotoflex couplings

PostPosted: Wed Mar 28, 2012 8:20 am
by 512BB
I have some bad news for all you elastically challenged folk this morning. The lovely Susan does not sell her cv driveshafts any longer, for Elans, only +2's. Notice how politically correct I have been this morning.

As has been mentioned previously, she was not happy with the quality of the cv's she was able to buy, due to premature wear, caused by the angle of dangle on the Elan. She is still happy to supply driveshafts for the +2, as your dangle is less, as everyone who has been out with a +2 owner will testify.

Leslie

Re: Rotoflex couplings

PostPosted: Wed Mar 28, 2012 12:22 pm
by ftsoft
Thanks for the replies. I asked Ray at RD about the longevity issue and he had no evidence of it. I've been dealing with Ray for 30 years and have never known him to sell something that would be so drastically inferior. It wouldn't surprise me if the Portuguese couplers failed sooner considering the price difference. Anyway, CV joints aren't for me at this point. I'm thinking of buying the vise grip tool with the chain just in case. Being that the couplers have been in there for so long, I imagine getting them out will be an adventure.

Frank

Re: Rotoflex couplings

PostPosted: Wed Mar 28, 2012 2:52 pm
by alan.barker
sorry to correct you Carl but not all Sprints have failsafe pins on the driveshafts. I have a June 1972 Elan Sprint and has never had failsafe pins.
Anyway as for new rotoflex couplings, i remove the band before fitting and assemble 3 Jub Clips. I adjust using an old rear brake disk, so the holes align perfectly. The bands when new are not always in perfect line. Then the bolts slide into the holes using your fingers and no swearing or hammering. After many years working on Lotuses, i find it's the best way :mrgreen:
Alan B

Re: Rotoflex couplings

PostPosted: Wed Mar 28, 2012 5:47 pm
by trw99
Alan

Your Sprint should have the failsafe devices fitted. They were part of the Sprint package when the car was introduced, although I believe they had already been fitted to Federal S4s before then.

Due to the nature of their purpose (safety) and given the emerging risk of litigation in the Nader era, I would think it unlikely that the factory got rid of a few old 'unstrengthened' drive shafts as late as 1972. Having said that, I do know that a few Sprints ended up with different components fitted, for example a steering wheel without the Chapman signature. But as I said, I do not think even Chapman was playing it too cavalier by the 1972 when it came to safety.

Tim

Re: Rotoflex couplings

PostPosted: Wed Mar 28, 2012 6:12 pm
by Fred Talmadge
What exactly is this failsafe device and can I retro-fit to my S2?

Re: Rotoflex couplings

PostPosted: Wed Mar 28, 2012 6:45 pm
by nebogipfel
Fred Talmadge wrote:What exactly is this failsafe device and can I retro-fit to my S2?


They are little extensions to the centre line of the shaft and they protrude into the centre of the coupling. You could fit the later intermediate drive shafts to your S2.

Re: Rotoflex couplings

PostPosted: Wed Mar 28, 2012 7:37 pm
by Fred Talmadge
Could I weld a little stub onto the drive shaft?

Re: Rotoflex couplings

PostPosted: Wed Mar 28, 2012 7:48 pm
by rcraven
512BB wrote:I have some bad news for all you elastically challenged folk this morning. The lovely Susan does not sell her cv driveshafts any longer, for Elans, only +2's. Notice how politically correct I have been this morning.

As has been mentioned previously, she was not happy with the quality of the cv's she was able to buy, due to premature wear, caused by the angle of dangle on the Elan. She is still happy to supply driveshafts for the +2, as your dangle is less, as everyone who has been out with a +2 owner will testify.

Leslie


Last year whilst I was having some other works done to my Sprint at Paul Matty's they felt my rotoflexes needed replacing. After some discussion with them I decided to go for CVs, but later they got back to me and said they too were not happy with the present quality of CVs and couldn't recommend them at the moment. So I've had to have yet another set of rotoflexes.

Re: Rotoflex couplings

PostPosted: Wed Mar 28, 2012 8:02 pm
by TimMullen
No, not all Sprints have "fail-safe" couplings. They did have the "reinforced" couplings (the steel plates bonded into the rubber of couplings in-between the bolt holes.

My Sprint is one of the last ones that was brought over (made October, '71 and registered as a '72). It was even one of the two "show cars" that Lotus toured the major car shows with (although the twin cam Europa was getting all the attention at the time). I bought it in early '76, and I changed out the original rotoflex couplings (one had torn) when I bought it. It did not (and still does not, although I wish it did) have the fail-safe couplings.