Summary of Dedion tube failures

[anthonym]

how much does a new DeDion tube cost?

and to fit?

and does the current version fit all previous cars such as both 2000 R500 and 1989 BDR?

 

 

 

Anthony

[Ian B]

Can't comment on failure of the ears, but if yours has the 'gusset' plates fitted to the damper mounts like this then it should be OK, if not you need to be aware that this type of failure is well known.

 

As far as i know all new Dedions are now supplied with the gusset plates, and are thicker material, but CC will advise on how retrospective the fit is (there are narrow and wide centre butresses for example).

 

Cost is just shy of £300 at present here

 

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Ian - Slightly Vider SVelte SuperVeloce model 😬 - Joint AR for North Kent

[anthonym]

the CC Shop entry says used since 1996, but am I right in understanding that does not mean used in its present form since 1996?

 

Anthony

[Ian B]

That's my understanding as well - the detail has changed.

 

Simplest check is to see if you have the damper 'gussets'

 

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Ian - Slightly Vider SVelte SuperVeloce model 😬 - Joint AR for North Kent

[anthonym]

how much time for a professional to remove and replace a new DD?

 

 

Anthony

[Irrelevant]

how much time for a professional to remove and replace a new DD?

Hour or so . . I guess.

[anthonym]

Questions:

 

do we know how many of these have failed without any warning at all? This would mean no amount of visual inspection would help.

 

To what extent do we accept that these may be (if at all) the result of being kerbed with force, such as on the race track?

 

Do we or not, accept that not all items are at risk? What I am getting at here is whether the fault is a design fault or whether it may be say metal fatigue or more simple excessive forces ()such as i mention above).

 

At present I have presented to me what I see as two opposing views that:

 

up to a certain age: (edit: see my own reply to this post below)

 

1 - all cars are at risk

2 - not all cars are at risk

 

edit: it seems that car above a certain power and type of use may be the ones at risk

 

Note that practically 100% of my driving is along precipitous cliffs, this subject has my attention as I do not have any bushes or trees to spin off into.

 

Apparently the latest DD tube is 5mm longer than the rest, I am off to measure mine right now.

 

Anthony (0121 314 4750 in case you see this while i am doing the measuring and wish to chat)

 

 

Edited by - anthonym on 16 Oct 2009 09:40:55

 

Edited by - anthonym on 16 Oct 2009 14:36:07

[anthonym]

Answers:

 

mine is a pre-gusset DD and looks just fine.

 

The DD measures 115.3 cm from inside ear edge to inside ear edge.

 

Having lain under the car for a while looking at all this, I can see how using the centre of the DD tube as a jacking point is perhaps placing an unexpected weight in an unexpected direction on the DD around its middle. The DD is not the chassis, though where to put a jack? The towing eye? In any case my jack is one of the quick lift variety and not using the DD ("crucifix" as borrowed from the term used for the front of the car jacking point used by many (inc me)) centre would be a real nuisance.

 

From what I have read there are two failure points: (1) around the middle - there is a pic of one broken as such and (2) the rest seem to be around the damper mounting points.

 

Following on from that these two possibly allow for different causes and arguments capable of being put forward seem to be:

 

(1) around the middle caused by (excessive? meaning long periods and / or often) the car being suspended from the middle of its DD AND (apparently) the incidence of low speed incidents suggests power being the issue: they break under load (which intuitively makes sense too, more than the jacking point idea)

 

(2) (damper mount points) Kerbing has been suggested (mainly track I think) for the damper supports; though strikes me once weakened, the power mentioned at (1) above will also contribute.

 

In both cases, to consider the "no warning" element, once a crack appears in its first instance, it may well be very little time before complete failure, so a visual inspection "last week" may well be far too long ago in this context.

 

I am actually wondering if an inspection by feel might even be better, if I can reach with my hands/fingers to the damper mount points and either side of the central bracing each time out, that would give me tactile feedback; where metal should be smooth, any problems should show up as "not smooth".

 

Latest (today being 16 Oct 2009) DDs are

116.3 cm long, being 1cm longer as a development to allow for 8" wheels to be a bit further from the radius arms, in the pursuit of perfection. Also they are checked for alignment post production, again as a development (not suggesting they were not in alignment in the first place, just an extra check).

 

Mine at 115.3 is clearly an earlier version (looks like version 3 to me at post one of this thread (for which thank you for the "heads up".)

 

edit:

 

There is a third point of failure, the ear to the weld or the weld to the tube.

 

All failures are seen as power related on high power cars used to their max.

 

The damper mounting issue is addressed by the extra triangle of metal welded on for strength.

 

A long bolt can be added from one ear to the other right through the tube, as belt and braces. This is a 116.3cm tube item, a couple of washers could be used for the 115.3cm tubes.

 

"b" These failures are not likely to be instant and are likely to be found by regular visual inspections.

I am not clear about how to inspect for the ear failure. (Ear meaning the ear on the tube, NOT the alloy ear).

 

edit:

 

How to measure the DD without tears (e.g. for accountants like me)(i.e. without dismantling anything): a metal reel rule (so not a ruler), lift rear of car (I poked the rear out off the end of the trailer on its ramps (keeping the car attached to the winch), while lying under car abut rule end against inside edge of an ear, run rule along DD tube to inside edge of other ear; then spend ages trying to see if it is 115.3 or .4 cm The latest is 116.3 so you can at least see if yours is NOT 116.3 and more like (Say) mine at 115.3cm (I took some pics so blatmail me if you'd like to see).

 

Anthony

 

This post contains my finding and understandings or lack of them.

 

 

Edited by - anthonym on 16 Oct 2009 14:33:11

[Ian B]

Hi Anthony,

A couple of comments:

All failures are seen as power related on high power cars used to their max.

Not from the information I have, certainly relating to the damper mounts. The power of the car does not seem to have a bearing on it and any power car can be affected.

The damper mounting issue is addressed by the extra triangle of metal welded on for strength.

as well as increasing the dedion tube wall thickness.

 

YHM

 

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Ian - Slightly Vider SVelte SuperVeloce model 😬 - Joint AR for North Kent

[Ian B]

BTTT for those winter fettlers to check

 

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

[Racing Snake]

Thanks Ian

After seeing Bio's failed D/dion tube last year i will be under my 7 in the morning

 

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Mad Hatter Racing - Feel The Duralight R Torque 😬 Carl

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[JFoX]

If you recognise your entry and think it contains inaccuracies, or you can add the car year, mileage or Dedion Version number, then please either post here, or to remain anonymous blatmail me to let me know, and I’ll try to keep the above updated.

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I am "failure 12" in the original post.

 

My DD tube failure happened in Feb 2005 and I gave details to Ian soon after. Then BC became members only. Then I became a member. Then here I am, giving more details to anyone who feels the need fore more info.

 

Car is a 1991 LHD BDR, factory build.

Mainly used on track by 1st owner (15000km). Mix track / road by me (+30000km). Stock specs (150ish BHP).

Tyres : Yoko A032R / Toyo R888, much grip hence much struggle on the tube.

Failure mode : the same as failure 21

DD version : was 2, replaced by 4 after the failure. I can confirm v4 is much heavier (because much thicker) than v2.

No warning before the failure, but I have to admit I spend more time in the car than under it....

As Ian mentions in the first post, there were

some contact marks on differential where it could have contacted the Dedion tube.

The rear diff mounting which should be cut off was still on, and seemed to have fouled the DD tube. It could have caused similar stress than a "crucifix" jacking.

 

I think that last point is worth a quick check. I could even hacksaw the bit in situ (boot floor off job).

 

Replacing it was quite straight. 3 spanners on a scale from 1 to 5. Wheel hubs come in 1 chunk with ear, disc and caliper. They can be suspended to the top end of the damper if you don't want to disconnect the brake line. Then the tube goes out by the side of the car (check lateral clearance before !).

 

I hope that thread will help many of us to avoid that scary wobbly rear feeling...

 

JFoX

 

Edited by - JFoX on 18 Feb 2010 12:35:49

[Guy Lowe]

Only just read this thread I had a DD tube fail on the way back from the 50th event in Norwich 2007..  I was doing about 35 when the rear of the car suddenly stepped out to the middle of the road and crabbed along. I had no warning before this but had done some 'hot' laps of Hethel in the afternoon and this happened just before Bury St Edmunds, some 36 miles later. The failure was exactly like "FAILURE 21" in Ian's pictures, no sign of any corrosion and it appears to have started at the weld of the buttress. The car is a 1991 and had done about 16,000 road miles. Arch sand blasted and re powder coated the chassis including the tube in 2004 when I did a ground up rebuild. At no time did they or I notice anything wrong. The tube I replaced it with was part number 79106 (Version 2 narrow buttress) however the part description on the CC invoice also says "H.D. 10 GAUGE". I have always jacked from under the diff, but the previous owner could have used the tube as a jacking point. It was an unpleasant experience which thankfully happened at low speed (we were in convoy and had been pushing on a bit down the A134 before slowing down when entering Bury S E ). 

[Ian B]

Thanks for the info Guys, 1st post and photo links updated

 

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

[eric]

the good idea is to change your de dion tube by a new one

if you have a doubt.

 

In France there is some accident known as the car are old now

[Ian B]

Number 26 added. In 2009 CC told the owner they had only seen this on race cars that have been driven over the kerbs 😔

 

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

[Ian B]

With all the potholes around now, remember to check your damper mounts (especially the front side) for signs of them cracking and peeling away from the tube

 

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

[irrotational]

I kept meaning to say a big thanks to Ian for this thread - I got more and more worried about my tube as it was of the classic type to fail (3?).

 

I replaced mine last year and so far the rear wheels are still attached.

 

It may well have saved me from a nasty accident somewhere down the line

 

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my mind is blank....

[combine]

Learning curve big time for me , so I'm not the only one , thank god the wife and I are still alive and not the other side of the road !

[Ian B]

Thanks Irrotational - I just hope no further failures cause accidents ☹️

so I'm not the only one , thank god the wife and I are still alive and not the other side of the road

Combine glad you (and mrs. combine) are OK. Did caterham say "we've not seen one of those before"?

 

If you've got any pictures of the break, and don't mind them being added to the list on page one, please blatmail me and I'll tell you where to email them

 

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

[combine]

Ian , CC said ' Probably metal fatigue , or someone must have been in an accident in your '7' before you owned it ( I'm 4th owner ) , oh , it is 20 years old anyway ( its 19 ). Must admit I was not happy at these comments . Haven't taken any pics yet . Also am wondering which version of the de dion I'll get in the post/carrier ? Pic 21 & 25 are identical to my break on tube.

 

Edited by - combine on 9 Jun 2010 21:29:28

 

Edited by - combine on 9 Jun 2010 21:35:57

[Ian B]

CC said ' Probably metal fatigue , or someone must have been in an accident in your '7' before you owned it ( I'm 4th owner ) , oh , it is 20 years old anyway ( its 19 ).

Can't say I'm I'm surprised 😔

 

Any photos for the archive?

 

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

[anthonym]

Well, my new dd tube is on its way to me with some other goodies and two "fixing kits" (nuts and bolts, seems sensible to change them in any case. )

 

I engaged CC about thgis a while ago (around the time of my earlier posts in this thread) and received some replies I found interesting. That is to say interesting in the context of how what my wife sees as "back axles breaking without warning" context. I characterise these replies as "polite blocks". No willingness to share information and no recognition of anything being amiss at all. So I left it there - I believe Ian has done a tremendous job of collating info and engaging CC.

 

So. I put my business hat on and wondered what would be the consequences of a recall?

My unscientific conclusion is that might be deeply deleterious to my favourite car maker and as such perhaps not such a good idea. However, I think the price of the new items, in view of the history, is excessive and these items should be made available at massively reduced cost. I would see this as tacit recognition that some of us may not be comfortable continuing to drive our cars in view of this history - and I have two of them, both with suspect items.

 

Anyone want to buy my old DD Tube? Undamaged (on visual inspection), the version 3 circa 1999 just before the additional welds......

 

Indeed, how would I feel about selling it to anyone? Maybe for track use only, in full knowledge.

 

I suppose this is one of those things that everyone sees as happening to someone else, until the day arrives - at least that's how I see the response to this thread.

 

My 2p.

 

Anthony

 

[combine]

Yes , agree , could do with a reduced price de dion and yes they should have done a recall. We had a recall a couple of years ago on our landcruiser back axle , something about bolts coming loose , ( our truck seemed fine ) , they paid for everything including a hire car while job was done and cleaned and polished landcruiser inside and out , thanks Toyota ! We have just bought a second one to add to the fleet for the wife. How about that CC .

[The Outcast]

I think the most annoying aspect is that a member was summonsed and found guilty of careless driving as a result of a Tube failure [which can be catastrophic if it happens as you hit a bump at speed.] Mine certainly went that way and put me in the ditch BUT I was lucky as it was an empty road, In traffic the result could be nasty.

I can understand CC keeping a low profile after all most failures are age related and well outside any warranty there where thousands of cars fitted with the unbuttressed tubes so the expense could have very very bad consequences for such a small manufacturer and I suppose if driven very carefully some tubes may last the distance. But as time progresses we are seeing more and more on this forum and obviously have no idea how many are failing elsewhere with folk who have no idea of the history and presume it's an isolated incident. I'm on my third tube now as after my original failure CC admitted that the replacement batch where all faulty and BRUCE had to replace all of them. ☹️