paul jacobs Posted June 7, 2002 Share Posted June 7, 2002 Has anyone else had a problem with the lower shock absorber bolt ripping open the DD tube, where the metal bush is welded on underneath it? NB - This won't apply to earlier cars in which the bolt goes through the tube. I'm waiting for JC [no not the religious JC, but the one at the factory] to get back to me on Monday, but have requested another DD tube as a goodwill gesture, as, even though the car is now 5 years old, I don't feel that this should ever happen to a car in its' lifetime. Anyone got any thoughts or similar experiences? I'd better mention that my car is a Vx 21, but all the components are identical to and interchangeable with, Seven parts. Link to comment Share on other sites More sharing options...
Stijn LUYCK 1 Posted June 7, 2002 Share Posted June 7, 2002 Paul, lot's of people had this problem before ... some found it out the hard way, I luckly enough noticed it while changing the rear shock absorbers. In my case a hair crack developed at the weld ... a few more curbs and god knows what could have happened. Two reasons that can exagerate this "weak link" are badly tightened bolts and riding on the bump stops. I now have the habit of checking EVERYTHING reguraly ........ Link to comment Share on other sites More sharing options...
Marius Posted June 7, 2002 Share Posted June 7, 2002 Paul, a friend of mine experienced the same fault, going down to Foxhole on the Nuerburgring in 5th flat out. He guessed that excessive curb-riding might have weakend the weld and now only uses the upper mount. I´m also thinking about switching to the lower one to lower the rear end further but all these stories are currently making up my mind... Marius P.S.: 2001 race season Caterham video, Spa Eurocup, Joachim Westermann, 3rd lap, Bus-stop chicane, DeDion cracks right in the middle.... Link to comment Share on other sites More sharing options...
stevefoster Posted June 7, 2002 Share Posted June 7, 2002 I check mine regularly.. yes the tube welds too! Hard curbing isn't my style but at somewhere like curborough you have to don't you. Steve My racing pics hereid=red> Hants (North) and Berkshire area club site hereid=red> Link to comment Share on other sites More sharing options...
V7 SLR Posted June 7, 2002 Share Posted June 7, 2002 Now you've got me worried. Whilst inserting the bolts above the shockers for the roll cage I noticed that shocker was damaged as it had been bolted too close to the de Dion, causing a cut in the shocker casing. It's not serious damage to the shocker but there's obviously stress induced. I better go and check if there's enough room to space it off the tube a bit. Link to comment Share on other sites More sharing options...
paul jacobs Posted June 8, 2002 Author Share Posted June 8, 2002 This seems to be a bit of a weak area. I haven't been riding kerbs or had loose shock absorber bolts, so can only infer that it is due to the extra weight that the car can carry in the back, although frankly, apart from putting some fairly lightweight camping gear in for Stoneleigh, I usually travel with it virtually empty. It just seems to be an item that doesn't seem strong enough, I notice that the latest ones have a small bracket welded on now, perhaps this helps. Link to comment Share on other sites More sharing options...
stevefoster Posted June 9, 2002 Share Posted June 9, 2002 I haven't seen the 'new' add on bracket. It would seem a good idea. The alt is the old style springs. I would like a VX race set really. Steve My racing pics hereid=red> Hants (North) and Berkshire area club site hereid=red> Link to comment Share on other sites More sharing options...
millsn Posted June 10, 2002 Share Posted June 10, 2002 Steve I think that to run shorter springs (assuming similar rates) in order to use the upper pick ups on the tube you'd want to use the shorter damper bodies too. Careful what valving you end up with. Nigel Mills - 2.0 Zetec carbs Link to comment Share on other sites More sharing options...
stevefoster Posted June 10, 2002 Share Posted June 10, 2002 Yep. springs and dampers. I assume the race poundage of the springs would be to great for the dampers I have... Steve My racing pics hereid=red> Hants (North) and Berkshire area club site hereid=red> Link to comment Share on other sites More sharing options...
Richard Ince Posted June 11, 2002 Share Posted June 11, 2002 I have had two occasions this year when the end plate has broken off. Scary moment! Caterham have now made made up some heavy duty tubes. Link to comment Share on other sites More sharing options...
Graham Perry Posted June 11, 2002 Share Posted June 11, 2002 Broken end plate, now that should take some doing as the metal is pretty substantial in that area. I don't like this new lower position for the spring mounts it just looks like an afterthought and this forum has now heard of several cases of failures, so from what Richard Ince says it sounds like Caterham must be re-thinking the design (again) Due to this worry, I recently had my original 1990 tube crack tested after several years of 'heavy' sprinting (my brother and I are both on the wrong side of 100 kg ) and was surprised to discover that the only cracks were in the 4 corners of the central triangular butress, where it mates to the tube. The very experienced welder who repaired it said that the cracks that were there had been made when the original welds cooled and fractured through contraction, rather than load. Link to comment Share on other sites More sharing options...
tbhall777 Posted June 11, 2002 Share Posted June 11, 2002 Should Caterham not perform a recall, or are they waiting for somebody to die. It will happen sooner or later. This component should not fail period. Link to comment Share on other sites More sharing options...
Peter Carmichael Posted June 11, 2002 Share Posted June 11, 2002 It is difficult to envisage a cheap solution. Are you serious in imagining a recall by Caterham? Most failures are linked to track use over kerbs and loose poorly maintained bolts. Agree that this is a component that it is difficult to imagine a safe mode of failure. Peterid=teal> 253 BHP K-seriesteeth.gif, no gearboxbum.gifid=red> Link to comment Share on other sites More sharing options...
Richard Ince Posted June 11, 2002 Share Posted June 11, 2002 I was told by a welder that when the end plates was mig welded the joint was cold. This allowed the joint to fail and for the plate to break away from the tube. I was 2 inches away from hitting the Armco when I stopped. I have subsequently heard that one of the top Superlight drivers had a major crack in the end plate but it was noticed between qualifing and the race. Caterham do not agree with me that the weld was faulty. Link to comment Share on other sites More sharing options...
Chelspeed Posted June 12, 2002 Share Posted June 12, 2002 As I'm using the original damper mount I guess the large number of de dion tubes with the bottom mount torn off would make a handy source of spare tubes for me. No, on second thoughts perhaps not such a sensible idea.... Link to comment Share on other sites More sharing options...
elie boone Posted June 12, 2002 Share Posted June 12, 2002 I have seen some De Dion tubes where the welding was poor especially on the damper mount even to the point that i couldnt believe it was a factory part. IMHO Caterham put the damper mount below the tube to be able to fit the longer and softer proggresive springs. Link to comment Share on other sites More sharing options...
paul jacobs Posted June 13, 2002 Author Share Posted June 13, 2002 Yes, I did wonder why they would use, what, at first sight, looked like an inferior attachment for the spring/damper assembly? Link to comment Share on other sites More sharing options...
Peter Carmichael Posted June 13, 2002 Share Posted June 13, 2002 Found this in the 2002 Superlight race regs: De Dion tubes should be changed as a matter of course following an accident. It is recommended that De Dion tubes are regularly inspected for damage. Failure to tighten damper securing bolts to the threaded bushes may result in the bush being torn out of the tube. A revised version of the existing tube with stiffening gusset to the damper bush has been introduced in 2001. This tube is legal and retains the same part number (79028) as the previous version. Peterid=teal> 253 BHP K-seriesteeth.gif, no gearboxbum.gifid=red> Link to comment Share on other sites More sharing options...
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