MAURY712 Posted May 16, 2008 Share Posted May 16, 2008 today I think I went next to big problem Indeed, the upper part of the steering column is broken ! Fortunately I was riding gently !! and i stoped immediatly with a big play with the steering wheel ....then Repatriation of my 7 in my garage. this evening i have remove all the parts fron the upper steering column for inspection, and there is nothing to accuse exept this upper steering column. bushes are almost new ,the universal joint on the steering rack is in good order.. It s very dangerous, 😔if i were on circuit or driving fast on the road.... Is someone already have this trouble 🤔 1996 road legal 7HPC Link to comment Share on other sites More sharing options...
Dickie Normuss Posted May 16, 2008 Share Posted May 16, 2008 Is it the original fixed column or a removeable one? It should be quite easy to see where the problem is. Have you checked the clamp above the footwell that joins the two parts of the column together? VX HPC - Loud and proud here Watch out, whatever hits the fan will not be distributed evenly Link to comment Share on other sites More sharing options...
MAURY712 Posted May 16, 2008 Author Share Posted May 16, 2008 Thank you for your answer. It s a standard steering with moto-lita wheel . yes i have seen the clamp and i think it was too tightened What do you think about 🤔 1996 road legal 7HPC Link to comment Share on other sites More sharing options...
stevefoster Posted May 16, 2008 Share Posted May 16, 2008 I suppose over tightening of the clamp grub screw could strip its threads or same with the bolts and cause it to become loose... To correctly secure the upper clamp (assuming its in an ok condition) screw in the grub screw so it is proud by 0.5 or perhaps 0.75mm and then tighten up the two bolts on either side evenly. Use thread lock on all. Doing this loads the grub screw in a way that you cannot achieve by simply tightening it with an allen/hex key. It literally digs into the opposing steering column face - if you were to disassemble a correctly mounted clamp you would be able to see a little ding from the grub screw point if it's been done properly. This should then be permanent. Don't forget to add lightness :-) My 2002/2003 racing pics here General pics (mostly of 7's and cars). here Link to comment Share on other sites More sharing options...
MAURY712 Posted May 16, 2008 Author Share Posted May 16, 2008 Thank you for these instructions about the timing of the clamp. the upper steering column is broken above the clamp 10mm at the end of the machining. I am very scared even i will replace all the parts,i i dont find what is the trouble......... 1996 road legal 7HPC Link to comment Share on other sites More sharing options...
stevefoster Posted May 16, 2008 Share Posted May 16, 2008 Oh that is scary. I wonder what cause that. Mechanical or material imperfection causing failure is rare but... Can you post some photo's somewhere? Don't forget to add lightness :-) My 2002/2003 racing pics here General pics (mostly of 7's and cars). here Link to comment Share on other sites More sharing options...
MAURY712 Posted May 16, 2008 Author Share Posted May 16, 2008 Yes I can send some pictures ,but i dont know where and how to do ? exept by email I am a novice 1996 road legal 7HPC Link to comment Share on other sites More sharing options...
DaveMorris Posted May 16, 2008 Share Posted May 16, 2008 I don't know exactly what happened to your column, but .. .. .. a POTENTIALLY similar thing happened to me 3 years ago, though for me the column sheared/seperated right at the top of the machined section. Essentially the machined cut-out to allow the clamp to be fitted SHOULD be radiussed.On my column the machining had square-cut corners and (I believe) this caused the start of a stress induced crack that propogated all around the column. You cannot easily see the top of this cutout without removing the upper column. I wasn't quite as lucky as you - mine eventually failed at ~50mph (80kph) and resulted in "a bit of an off". Thankfully I was running in a new engine at the time and so not pressing on too much. I now have the top section of column on a maintenance schedule for inspection. I don't think that this is, in any way, a regular occurrence - just a BIG ISSUE when it does happen 😳 Link to comment Share on other sites More sharing options...
Beelzebub Posted May 16, 2008 Share Posted May 16, 2008 Has anyone got pictures of a failed column ? I think this would be in everyones interest to know more about these failures. The consequences of the column separating at speed or under cornering loads don't need spelling out. Dave. Link to comment Share on other sites More sharing options...
DaveMorris Posted May 16, 2008 Share Posted May 16, 2008 Somewhere I've got pictures of the failed column + the consequences. Will get round to posting (though not right now) In-fact IIRC - somewhere I've got the old bits of column. Link to comment Share on other sites More sharing options...
CageyH Posted May 17, 2008 Share Posted May 17, 2008 Salut Maury712! Si vous m'envoyez les images, je les mettrai sur le Web. email link Une autre 7 en Aveyron? J'ai jamias vu une autre 7 dans le departement. Ma future épouse est un Aveyronaise (St Amans des Cots). Je prends souvent mes 7 à l'Aveyron. Il y a beaucoup des routes fantastiques ! J'aime la region. Edited to fix the e-mail link... Edited by - CageyH on 17 May 2008 16:32:52 Link to comment Share on other sites More sharing options...
Jason Plato Posted May 17, 2008 Share Posted May 17, 2008 Gagey *arrowright* 😬 looks like Billy has found a mate 😬 🥰 🥰 🥰 here is C7 TOP Taffia rear gunner Link to comment Share on other sites More sharing options...
CageyH Posted May 17, 2008 Share Posted May 17, 2008 Gagey? Pieman, It's quicker to fly back to the UK.... Only dead fish go with the flow....! Link to comment Share on other sites More sharing options...
Mickrick Posted May 17, 2008 Share Posted May 17, 2008 DaveMorris, still thinking of ditching the screen? 😬 Academics are seldom any use at engineering. One must have a mistrust of theorists. (Keith Duckworth) Link to comment Share on other sites More sharing options...
DaveMorris Posted May 17, 2008 Share Posted May 17, 2008 Mick, on recent re-build of the supersprint I've got 2 scuttles.One for the black-pack screen, the other for an aero (no drill holes). So in some ways I am thinking of going screenless, but as I'll probably end up selling the S'sprint and keeping the HPC I might never get to savour the experience. Aeros are no good at snapping barbed wire as you go through the hedge anyway. I reckon that screen supports are so much stronger than my neck 😳 Have you decided on the spec of your new one yet ? Link to comment Share on other sites More sharing options...
Mickrick Posted May 17, 2008 Share Posted May 17, 2008 DaveMorris, YHM. Academics are seldom any use at engineering. One must have a mistrust of theorists. (Keith Duckworth) Link to comment Share on other sites More sharing options...
CageyH Posted May 17, 2008 Share Posted May 17, 2008 Pictures now available here... Only dead fish go with the flow....! Link to comment Share on other sites More sharing options...
Mickrick Posted May 17, 2008 Share Posted May 17, 2008 I think those should be sent to CC with a read reciept, so they are aware of it. Academics are seldom any use at engineering. One must have a mistrust of theorists. (Keith Duckworth) Link to comment Share on other sites More sharing options...
stevefoster Posted May 17, 2008 Share Posted May 17, 2008 [Monty Python Eric Idle voice on] In all my years of 7'ing I've never heard or seen such a thing, until now... A balm, what are you giving him a balm for? It might bite him... [Monty Python Eric Idle voice off] Don't forget to add lightness :-) My 2002/2003 racing pics here General pics (mostly of 7's and cars). here Edited by - stevefoster on 17 May 2008 22:40:14 Link to comment Share on other sites More sharing options...
CageyH Posted May 17, 2008 Share Posted May 17, 2008 The question is, what could have caused the column to break in such a way? It is not broken where I would have expected it to go. I feel relatively happy about the condition of moine, as I replaced the upper part last year, but I think people with older cars should check for signs of cracking. Only dead fish go with the flow....! Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted May 17, 2008 Share Posted May 17, 2008 It doesn't look nice 7 related photos Link to comment Share on other sites More sharing options...
Julian Thompson Posted May 18, 2008 Share Posted May 18, 2008 When I got involved with my big rebuild this winter I decided to sort out the column once and for all. I was aware of the failure suffered by Dave (Morris) and will confess to never feeling comfortable with the principle of the design behind the standard column. I have gone for a one piece tubular column - deciding that the danger of losing the 'collapsible' part of the column is less than the danger of a snapped column due to this kind of metal failure - or even failure due to the clamp coming loose etc.. Link to comment Share on other sites More sharing options...
rj Posted May 18, 2008 Share Posted May 18, 2008 I guess this is why the current design has a radius rather than a sharp cut. Shearing always starts form sharp edges... Link to comment Share on other sites More sharing options...
CageyH Posted May 18, 2008 Share Posted May 18, 2008 RJ, Agreed. Known as crack propagation. You can also get stress related failures caused by corrosion. Link to comment Share on other sites More sharing options...
Bob Simon Posted May 18, 2008 Share Posted May 18, 2008 When examining my column, I noted that the hole was drilled with a rather dull bit at a high feed rate leaving a nasty row of ringed grooves inside. The notch had no radius. Lots of nice stress risers for crack propagation. I've since fitted a CoMo steel tube with a nice radius in the notch area. Saves a bit of weight as well. -Bob 94 HPC VX Evo III Link to comment Share on other sites More sharing options...
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