ISmall Posted October 25, 2000 Share Posted October 25, 2000 My suspected De Dion tube fracture has in fact been confirmed as the radius bolt on the driver's side sheering off in the bush. Red Line took the bolt out this morning and it's not up to spec for the job. I've got a 1996 1.6K SS and I understand that at some point in the last few years the bolts on new cars were of a higher grade of metal. I'm amazed that a thing such as a radius arm is held on by a bolt that is no bigger than the one I have on my Flymo keeping the handle in place!! At the risk fo sounding like a broken record, this failure could have been fatal in other circumstances and was pretty hairy when it happened. Surely Caterham should have issued a general advice notice to owners informing them of the potential dangers of weak bolts in that area and recommending replacement. This needn't have incurred any cost to them, and it's a damn site cheaper than a law suit! Link to comment Share on other sites More sharing options...
Dominic Berry Posted October 25, 2000 Share Posted October 25, 2000 ISmall Any idea when the bolt was upgraded? I have a '99 1.6k SS and this sounds a bit worrying. Can you post the details of the new bolt up so I can check what I've got? Dominic Link to comment Share on other sites More sharing options...
Jules Martin Posted October 25, 2000 Share Posted October 25, 2000 I lost the bolt in the offside rear Watts Linkage right on the Apex at Copse at Silverstone. The axle twisted, and at over 100mph I was very lucky to keep the car on the road. The solution was so simple, I just drilled and wired both bolts (though the nearside is probably unnecessary since it tightens with use)to the chassis. Cost;- a few pence. Since this happened I have been told by Hyperion & Arrowstar that they do this as a matter of course, for safety reasons. Jules thumbsdown.gif Link to comment Share on other sites More sharing options...
ISmall Posted October 25, 2000 Author Share Posted October 25, 2000 I'm not yet sure what the code is on the new nut, but will let you know when I get it back. Caterham Cars have asked to see the old bolt to check it, but it's definitely not the best spec, hence the failure. The design of this linkage was changed to a threaded boss from a simple bolt through the chassis. I wouldn't like to go to the bother of wiring the bolts, and in any case that would have been useless for this case as it completely sheered off, wire or no wire. Link to comment Share on other sites More sharing options...
Dominic Berry Posted October 25, 2000 Share Posted October 25, 2000 I have the threaded boss so I assume all is OK with the bolt. Edited by - dominic berry on 25 Oct 2000 16:23:18 Link to comment Share on other sites More sharing options...
ISmall Posted October 25, 2000 Author Share Posted October 25, 2000 It's impossible to have a check done on all the bolts in the car based on the fact that some of them are safety critical. The radius arm bolts are clearly safety critical, but are they more important than a suspension bolt or one on the steering rack? The important thing is that the kits have the correct spec when they are delivered, and to a certain extent you have to have faith in the equipment as you see it. Not even Caterham can guarantee that their suppliers have done their job 100%. It's evident from the work done on my car today that there were 2 different types of bolt used in the radius arms on each side, which is a bit weird. To the untrained eye, both look the same. As I didn't build the car, I can't take responsibility for that error and neither can Caterham. I would suggest that all 7 owners check the code number on their radius arm bolts to make certain you have the right piece of kit. If necessary, check with Caterham to get it right. It's worth it, because I wouldn't like to go through that sort of control loss again (at least not one as unexpected as that!) Dominic, I assumed that all was well with my car until this happened because I had no reason to think otherwise. I have to admit that my confidence in it will need to be rebuilt which is a bit sad. A trip at the weekend with my foot on the loud pedal should do the trick! Link to comment Share on other sites More sharing options...
Pierre Gillet Posted October 25, 2000 Share Posted October 25, 2000 Is there a risk of stress/fatigue that would lead to sheering, and would it be prudent to replace periodically these radius arm bolts or any other highly stressed bolts? Pierre Link to comment Share on other sites More sharing options...
Graham Perry Posted October 26, 2000 Share Posted October 26, 2000 A stupid question perhaps, but which bolt fails, the one at the di-dion end of the arm or the other at the Chassis end ? I checked my ones at the Di-dion end on my 1990 car and they are very thick and would say that they would never break under a shear load,perhaps they used thinner ones on later cars ? The Chassis end ones are not quite as good, are these the ones that fail ? Link to comment Share on other sites More sharing options...
ISmall Posted October 26, 2000 Author Share Posted October 26, 2000 The bolt attached to the chassis just behind the seats. There's two possible configurations for the bolt. The top hole suits "road" driving and the bottom hole is meant for race conditions. Mine has always been in the lower slot and I've never used it on a track. I don't honestly think it would make much difference to the road-goer, perhaps a little softer ride. When the bolt sheers, the end left in the chassis could be a bu**er to get out because they tend to fuse a bit in the thread. Apparently the bolts tend to split at the top end of the thread, as mine did, where I suppose the strength of the bolt is weakest? The damage caused to my car was mostly cosmetic, because the axle slipped back and scraped the paint on the aluminium body panel behind. Other than that, no other work needed (apart from upgraded bolts on both sides). Quite lucky really. Link to comment Share on other sites More sharing options...
Paul McKenzie Posted October 28, 2000 Share Posted October 28, 2000 There was a report about shearing radius arm bolts I think in Low Flying 2 or 3 years ago - at that time kerbing the rear wheels was thought to be contributory. I called Caterham and had them send me two upgraded bolts to the new spec (minimum 12.9 HT)for my '96 HPC. The bolts they were using at the time were 8.8 I think. Link to comment Share on other sites More sharing options...
Pierre Gillet Posted October 29, 2000 Share Posted October 29, 2000 Paul, Mine is a '97 1.6 K. From your perpective, should I replace the bolts to make sure I have the new spec (minimum 12.9 HT)? Cheers, Pierre Pierre Link to comment Share on other sites More sharing options...
Paul McKenzie Posted October 29, 2000 Share Posted October 29, 2000 Pierre, The spec of the bolt is stamped on the head. Check to see if it's 12.9. If not, personally I would replace it. Link to comment Share on other sites More sharing options...
Pierre Gillet Posted October 30, 2000 Share Posted October 30, 2000 Paul, I just checked as you recommended and found the 12. 9 stamp. Ouf!biggrin.gif Best regards, Pierre Link to comment Share on other sites More sharing options...
Swiss_Tony Posted November 2, 2000 Share Posted November 2, 2000 I received two new nuts and bolts today. One had 8.8 on the end the other had nothing. These were wrong as my chassis is threaded. The correct ones will hopefully arrive tomorrow. I will see what they have written on them. If it is not 12.9 what should I ask for? James Link to comment Share on other sites More sharing options...
Pierre Gillet Posted November 4, 2000 Share Posted November 4, 2000 James, I would ask them to provide you wih the bolts stamped 12.9. Seems vital to me. Cheers, Pierre Link to comment Share on other sites More sharing options...
Jason Plato Posted March 17, 2001 Share Posted March 17, 2001 Checked my radius arm bolts today , the one required a few turns of the torque drive . Bit worrying how soon they can loosen ....... Best check them ASAP and put a tell tale on the bolt head . dave Link to comment Share on other sites More sharing options...
julians Posted March 17, 2001 Share Posted March 17, 2001 I had a radius arm bolt work itself loose on a track day recently, and the loss of control is not something I want to experience again, basically the bolt fell out and the car suddenly snapped round. I was travelling in a straight line at the time it happened on a nice wide peice of track. Had the bolt fell out whilt on the motorway or other normal road I would probably be dead. I have since replaced the bolt ,but have found it needs tightening every two track days, it is always the passenger side that works lose, the drivers side is still tight. I am going to get some loctite on it soon. Link to comment Share on other sites More sharing options...
Glenn Wheeler Posted March 17, 2001 Share Posted March 17, 2001 And I thought that I was the only person this had happened to, the same nearside bolt worked loose and dropped out as I was blatting along a lake district B road, the back end went like jelly as did my knees because minutes earlier I had been driving in an enthusiastic manner on the M6. I walked back along the road and found the bolt about 200 yards away, I borrowed a spanner from a nearby farmhouse and was on my way again. I think the lesson is quite clear, check all your nuts and bolts on a regular basis, I do now !! Take care Glenn Wheeler M17 SOK Link to comment Share on other sites More sharing options...
Allan Haighton Posted March 17, 2001 Share Posted March 17, 2001 For what its worth, I replace the suspension bolts fairly regularly on my live axle car and use sets of parts made up Caterham. The stamping on the bolts heads is usually 8.8 but there have been bolts simply stamped S. My local fastener merchant tells me that this is an 8.8 equivalent. Caterham don't do a better grade of bolt (I've asked) and my local merchant can't get small quantities. So 8.8 it is. Should I be seeking better? Link to comment Share on other sites More sharing options...
Graham Sewell Posted March 18, 2001 Share Posted March 18, 2001 Try buying your nuts and bolts from Namrick (Not sure of address) on the South Coast (possibly Brighton). They sell in single units if necessary in various grades including 'R', 'S' (8.8 equiv) and stainless steel (not for high stress work). Delivery by post is usually next day. Cheers, Graham Link to comment Share on other sites More sharing options...
Dartmoor7 Posted March 18, 2001 Share Posted March 18, 2001 I recently got two sets of bolts/washers/nuts from Caterham to enable me to change from top position to lower position. The bolts supplied are marked RSB and S. So they still don't consider a general upgrade necessary. Not entirely surprised. Link to comment Share on other sites More sharing options...
AMMO Posted March 18, 2001 Share Posted March 18, 2001 The reassuringly named Unbrako company make 12.9 bolts. I think these are only available in allen cap head. These are what I will use when I get round to changing the bolts (soon). They are not plated as this would alter the strength, so a coating of grease is not a bad idea. I'll use bolts which have as much shank as possible in the bush. This might mean using bolts which are longer than neccessary and cutting them down to length. The weakest point on a bolt is the root of the thread which is the narrowest point. I intend to machine a top hat to go next to the bush on the outside so if the bush becomes loose in the link arm it cannot come off. Not as good as having the bolt in double shear but better than nothing. On my car you have to remove the seats to remove the bolt as the nut is under the wheel arch. I may swap it over so the cap head and top hat are under the wheel arch and the nut is inside the car. Using a spanner to do up the nut between the seat and the bodywork it should be possible to change the bolt on a fairly regular basis. The postings I have read scare me stiff. The real solution is a re-design with a bigger bolt in double shear. As this is not a viable proposition regular replacement of the bolt is about all you can do. AMMO Link to comment Share on other sites More sharing options...
StewartG Posted March 22, 2001 Share Posted March 22, 2001 Just got a pair of these 12.9 super bolts from Allscrews in West Ealing for the princely sum of 2 quid not much to pay for peace of mind. Link to comment Share on other sites More sharing options...
serimmer Posted March 22, 2001 Share Posted March 22, 2001 Worrying, this list of sudden failures.? See my posting regarding wheel bearing failure:- This was instant, and on a motorway at 70mph. The car had done 20 miles since new and it had just had SVA & Post build check (obviously, of course). Thank god I hadn't gone for a 'test run' before the necessary legalities were complete, otherwise the boys in blue, who lifted me from the ditch, may not have been quite so helpful? How safe will I be in my next outing? Don't know why? (and can't explain it to my wife!) but I'm not put off. scott1 Link to comment Share on other sites More sharing options...
StewartG Posted March 23, 2001 Share Posted March 23, 2001 Should these bolts be done up tight, what torque, or should they allow the radius arm to move around the bolt as the bearing. There doesn't seem to be a sleeve type bearing in the bush, like say on the front wishbones, to allow movement or are mine so old that it's rusted solid in there. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now