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Summary of Dedion tube failures


Ian B

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I have the feeling (and that's all it is really, from reading here and LF classifieds over the years) that it is possible the vast majority of cars do hardly any mileage each year and only manage a few thousand over a large number of years - look at the two with that nice tale touring Spain in this months's LF (a good read I thought), one car had been moth balled for 10 years and the other for two - in deed I have a car unused for... more years than I care to think about.

 

I wonder .. I need to re-read the original post and see if mileages are given.

 

Anthony

 

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I'd be surprised if people haven't - the problem may get lost in a bigger accident when the car is just generally knackered...

 

Caterham seem to have dodged a very big bullet so far...if a fatality or something got attributed to this, they would be in big trouble - especially as there is tacit "evidence" on here of them ignoring it in the past...

 

 

 

I do wonder if an article on this would make it into LowFlying...I worry that non-blatchatters are blissfully unaware...

 

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my mind is blank....

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How many at risk tubes are out there?

Multiply by £300

= the risk at retail price

 

20,000*300

=6,000,000

 

Exchange the 20,000 with your own estimate.

 

Let's say product liability insurance covers actual claims, so that's covered.

Let's say insurance does not cover a recall, so that's not covered.

Let's say a recall would not be financially possible.

 

The business process is clear, if not moral.

 

So reducing the DD Tube price to buttons would encourage self replacement of any cars in greater use by owners aware of the issue.

 

A reasonably low priced including fitting exchange scheme (to get old ones out of the market place).

 

I suppose that any admission of any issue is in itself a problem because there will be those who simply expect a recall regardless of the consequences to cc. I keep wondering how many toyoda accelerator failures there were until recall was made. Here's how their press release deals with it http://pressroom.toyota.com/pr/tms/toyota/FAQ-for-Sticking-Accelerator-Pedal

 

Also occurs to me that an inspection service or even an "inspect your dd tube instructions" owners notice would address the moral aspect, or at least not leave owners in the dark.

 

I am replacing mine because practically 100% of my Seven driving is Alpine. This means that if my car spins/careers off the road even a metre or two it will be into a mountain chasm; no handy bushes here to break the fall.

 

I can't say I am comfortable writing about this subject in public, nor offering any appearance of telling CC how to run their business, but nor do I want myself or anyone else to die or be seriously injured for the sake of a car part I know has a history of failures. Back "axles" should not fail, ever.

 

Anthony

 

 

Edited by - anthonym on 13 Jun 2010 16:35:03

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I believe the moral aspect, which is not really a business imperative, would translate into a public relations (which is a business imperative) disaster of epic proportions; that's where the future damage would lie, aside from any successful damages claims (i.e. the tort of negligence - wilful or not failure to meet a duty of care).

 

This subject is the type of thing I have long and expressly stated is why we should have somewhere to discuss matters privately. I feel like that my writing of such posts could be harmful and yet there is nowhere else. I also suspect that more responses would be forthcoming if the discussion were not public. I have to be certain that none of us would wish any harm to come to CC or indeed ourselves.

 

Anthony

 

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You are probably aware that the MT have appealed for Tech items for LF so there is a great opportunity. *thumbup* It would have to be written with NO criticism or apportionment of Blame to CC but as a maintenance check item. *cool* With lots of pictures showing owners what to look for and photos of the removal and replacement procedure. This would reach every member of the club, and would not attract any negative interest against the Club from CC. 😶‍🌫️

So how about it Ian your in best position for such a project and have the literary prowess to so do??? 😬

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I wasn't aware of that. Having said that I haven't finished reading this months's LF, presumably it's in there somewhere?

 

Very Nicely spotted though in any case; I will be doing my usual photograph every step (see engine out) procedure when my new tube is fitted shortly (i.e. when it arrives here, sent the other day by CC.) so may be able to offer some pics.

 

 

 

Anthony

 

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*eek*

Clearly looking at this with major concern.

 

I have had my '92 (non-factory build) car for 10 years as the 3rd owner. I bought it off my best man and no surprises, it previously belonged to a guy who built it himself and tracked it. I would have thought that any horror stories that might be lurking would have reared their ugly heads or been picked up through servicing (JW does mine). Had rear end re-skinned following an 'up the chuff' dink, the work was done by the 7 workshop which included a complete dig out of various trees. So I'm hoping that any problems might have been found then?

 

Guess I'll have to go under and see what is what and perhaps change the tube anyway. Peace of mind can be quite expensive when you're all thumbs.... *rolleyes*

 

A

 

 

 

Edited by - Andy Lef on 14 Jun 2010 12:07:51

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Anthony, the older method of mounting dampers was using a bolt that went through the centre of the dedion tube, rather than through a 'boss' welded underneath it.

 

Outcast, it had crossed my mind, not sure about my "literary prowess" though!

Have a few personal items to deal with at the moment, so if anyone else wants to take up the pen please let me know, otherwise I may well start putting something together but it will have to be later in the year.

 


Ian - Slightly Vider SVelte SuperVeloce model 😬 - Joint AR for North Kent - Area details and calendar here
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Anthonym - as per Ian B's post - if you look at the pictures there is a rather large hole through the middle of the tube - the dampers used to be mounted there.

 

The part that fails was added on to accomodate longer dampers, and when it was originally designed, probably wasn't designed to be strong enough... 😳

 

---

my mind is blank....

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Yes please Gingerbread Man (or is that Ginger Breadman? *eek* *wink*), the more the better as it helps to build a picture of the failure modes.

Car age, mileage, type of use (eg road/track), and brief circumstances of failure or how it was spotted are all great (similar to list on page 1), together with some pics if you have them?

 


Ian - Slightly Vider SVelte SuperVeloce model 😬 - Joint AR for North Kent - Area details and calendar here

 

Edited by - Ian B on 14 Jun 2010 12:50:18

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Myles has written a description on his site which could be fleshed out for this (if he doesn't mind of course), in fact I am in the middle of doing that to reconcile nuts and bolts, fixing kits and part numbers with what work has to be done to replace the tube. Trying to create my own Ikea like instructions - flange A with bolt B type of thing, which reminds me the build manual Section 8 has copious details and torque settings, it all needs drawing together.

 

Edit: in fact mix together the build manual and Myles' description as each have what the other does not, plus part numbers and Bob is our uncle.

Expect the build manual covers only current models.

 

Anthony

 

 

Edited by - anthonym on 14 Jun 2010 12:52:59

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irrotional: if I understand you correctly, those holes were dropped from production - I think I got that from Ian's list. So I have to look see if mine has said holes for dampers.. presumably.

 

So here we are from op:

 

My version:

One of these two:

1997

Indent for Watts link bell crank added

2000

Buttress ends bronze welded

 

2004-present

Damper through-tube mount deleted

 

Penny drops: anyone with an older model will/may need/prefer through the tube holes which my existing DD Tube has never used - and these have never failed in that application? That's good news. edit, of course if none ever fail, no replacements will be needed. *confused*

 

Anthony

 

 

Edited by - anthonym on 14 Jun 2010 13:05:48

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Just found mine to be none servicable.

 

Near side shocker mounting (Lower welded on type) tearing away from the dedeon tube from above. Not detached yet but can put my little finger in the hole.

Found on inspection after renewing drive shaft boots on drivers side. I run my fingers round any handy welds when servicing and cleaning the car as a matter of habit.

Just back from a Scotland so suspect that some rough potholed roads are to blame. It was fine just prior to the trip. The tube is rust free and clean with the paint in good order on the outside. It has been waxoiled on the inside from new.

I think this failure is not due to corrosion but to inadequate strength at the point of the welded attachment of the lower shocker mounting tube.

 

!998 Superlight R, 25,000 miles and built by myself. Has longer shockers and watts linkage. I think it is a 'Version 3' so no real surprise that it has failed.

 

The car has been used enthusiastically but not abused.

 

If you need any more info please let me know and I will be happy to oblige.

 

S7MAD

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that is (perversely) a comfort to hear because as a precaution I am about to change mine on Sunday, 2000 R500 30,000 Miles. Also Version 3 - and it has done a lot of rough roads, has Watts linkage (don't know about dampers length). Extra thanks for your post.

 

Anthony

 

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  • 3 months later...
  • 1 month later...
  • 2 months later...

I changed mine (thanks to RJ's help) last year.

 

We were both wondering what to do with the old one - which appears to be in perfect order, being from a gently used R500.

 

:-)

 

The new one weighs a kilo more than the old one as I recall.

 

Anthony

 

 

Edited by - anthonym on 28 Jan 2011 15:41:28

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Why not get the strengthening bits welded on and it will be as good as a new one.

I had my tear welded and the strentheners fitted on mine as Caterham were 'out of stock', and it is now perfect.

Just a reminder that 'new' ones are wider than 'old' ones by a few mm. *wavey*

 

S7MAD

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