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Summary of Dedion tube failures


Ian B

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A close up of the current braced underslung damper mounts would be useful if you get a chance *thumbup*

 


Ian - MI 5EVN - Slightly Vider SVelte model 😬 now repainted to match the Autocom headsets (and AA recovery truck 😳)
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Well done Ian, your post has been really interesting to follow.

 

Although I'm not a owner yet I will be one day [soon I hope] and it is interesting to understand what I have to allow for and budget for in my purchase and ongoing ownership. Given the nature of an s7 I don't think you can tar them with the same brush as a main stream car manufacturer imagine the same problem on a GTI hot hatch!. An s7 is a racing car for the road in either a 100bnp or 300bhp form and given the limited production range and its unique place in the market you have to make some allowance it can't be even compared with Atoms and alike as the new kids on the block. The basis of the car we all know and love is 50 years old! In saying this people lives cannot be put at risk, and given the strength and longevity of this post it would be nice to see some sort of reaction from CC.

 

I have been following s7s since I was 9, I'm 48 this year and none of what I have read has swayed my following it would just be reassuring to hear a reaction to this post.

 

As I'm from an engineering background I also have to say has some of the problem come out of the amounts and levels of power that the chassis and drive train now have to take.

 

A Caterham is for life not just for Christmas!!!! *thumbup*

 

Ian, I'm pleased to see after all your DD trauma that you still have one and fly the flag.

 

Best wishes

 

Ian [Mr P]

 

 

Dreaming of a Se7en someday soon

 

Edited by - MrP on 13 Jun 2008 22:39:27

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Thanks for your kind thoughts Mr P *thumbup*

 

Darrens Photos of a new tube are now up here *thumbup*

 

 

Oh, and I've finally sorted out the numbering so they should all be correct now

 


Ian - MI 5EVN - Slightly Vider SVelte model 😬 now repainted to match the Autocom headsets (and AA recovery truck 😳)

 

Edited by - Ian B on 14 Jun 2008 18:22:43

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  • 1 year later...

Thought it was timely to bring this BTTT, as there was another dedion failure on the recent Alps tour.

 

Very lucky it wasn't on a mountain hairpin *eek* ☹️

 


Ian - Slightly Vider SVelte model 😬 - Joint AR for North Kent
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Bri, I've described the nominal 'versions' on the first page of this thread.

 

Version 3 is indeed before the gussets were added *thumbup*

 

 


Ian - Slightly Vider SVelte SuperVeloce model 😬 - Joint AR for North Kent
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It is important one they fail to change them NO amount of welding will EVER get the ear mountings back in their correct positions and the suspension geometry will be way out ,resulting in crazy tyre wear and poor handling. Unless you had Bruce's JIG you'd never get it right. *nono* 😬

 


jj

MTM , N.I. L7C AR 🙆🏻

Membership No.3927.

240BHP 1900cc K Series 40th Anniversary

 

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  • 3 weeks later...

1996 dedion. 100,000+miles, lots of trackdays and HEAVY use.

1x re-powdercoat in its life

No visible cracks and/or problems up until recent flat floor session (its first) where we identified 2.25degrees of toe at the rear of the car, disproportinately allocated between the two sides. suspect too heavy kerb usage or a pothole somewhere maybe.

 

Replaced with 2nd hand (albeit newer) dedion tube which is from what i can tell 10mm wider and has NO toe at the rear (unlike the original which has some).

 

I prefer the bent one! Has made the car handle very differently to before, however turn in is much better and the car feels more 7'esque on the handling. I suspect that this is as a result of reducing rear toe and therefore reluctance to turning has been removed.

 

So. Well done on first one for surviving heavy use.

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sounds like your tube was bent from jacking under the crucifix. I had the same issue.

 

Jonty, if you weld or straighten the tube and then check the alignment with a straight edge, the tube may need top be machined parallel at the ear mounts. But its quite possible to repair without the original jig. Bruce makes the tubes to +/-10min toe anyway so they need correcting even when new *smile*. Its only a tube with 2 chunks of steel plate on each end after all *wink*

 

here is my Duratec R .... C7 TOP

Taffia joint AO with Al

 

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Hi Ian,

 

You'll have to wait a little while longer for an answer - I am currently in the departure lounge at Montreal airport waiting for the flight home *smile*

 

I plan to pick the car up from James Whiting either Wednesday or Thursday and I will let you know any information that I may get regarding weights then.

 

Robin

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I'll grant you that one Dave BUT how many average owners [Not experts like you ] are going to be able to check the Alignment of those two bits of tacked on metal in both planes My comment was directed at Mr Average who would just bend the hedge tear back into place and hit it with the MIG. *wavey* *wavey*

 


jj

MTM , N.I. L7C AR 🙆🏻

Membership No.3927.

240BHP 1900cc K Series 40th Anniversary

 

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sounds like your tube was bent from jacking under the crucifix. I had the same issue.

Do you mean the 2,25 deg toe is result of jacking at the crucifix? I would expect that gives more likely some camber into the positive direction?

 

BTW: is the jacking there really that critical? I usually to do that ☹️

 

cheers Volker

 

 

German Sevener in Scotland

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I thought that jacking under the crucufix, was the only sensible place to do it. Or so I've been led to believe many times on here 🤔

 

Confused now!

 

Do tell..........

 

Nigel.

 

C7 FST....Powered by DVA

 

A Wolf in Clams Clothing!

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*arrowup* *arrowup*It looks like they are referring to the A-frame to DeDion tube bracket as a "crucifix". I can see how this could cause the dedion to bend but must admit that I have often used this point to jack the rear of the car. Is it better to use the diff or should it be done using the outer chassis frame by the towing eye (where I always put the axle stands)
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I was indeed referring to the triangular section of the dedion that the A frame attaches to as a crucifix.

 

I bent my tube in this way - not in one action but over the course of several years.

 

the camber changed but also the toe altered as the tube went banana shaped.

 

I would advise that the link to the tech wiki contains wrong information. I also wouldn't jack under the a frame front bush as on many models this is in single shear with a bolt going into the bush on the chassis .

 

I now jack under the diff or from the rear toe eye

 

here is my Duratec R .... C7 TOP

Taffia joint AO with Al

 

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  • 1 month later...

oh dear ... just come here from here

I have a 2000 K R500, ordered 30 May 2000, built by October 2000 so may have a version 3 DD. And one about the same age failed on a recent Alps trip. I have Bilsteins.

 

I am trying to understand how this thread may apply to my car, so anyone who has figured out the same for their similar car, please chime in.

 

Anthony

 

And http://www.blatchat.com/t.asp?id=118927&pn=3&ps=15

 

http://www.blatchat.com/t.asp?id=18773

Edited by - anthonym on 15 Oct 2009 19:35:07

 

Edited by - anthonym on 3 Jun 2012 17:01:16

 

Edited by - anthonym on 3 Jun 2012 19:55:06

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