EFA Posted April 20, 2002 Share Posted April 20, 2002 Today I found one of the allen bolts which pass through the lower damper mounting on the front wishbone had snapped. Over half of the bolt had dropped out, and it was sheer luck the partial failure was spotted during some other fine tuning of my suspension. - A total failure would without any doubt have resulted in collapse of the nearside front suspension with obvious consequences. I sugggest you check you can see the heads of these two bolts (one on each side of the car) to be sure things are OK. If things are wrong the head and a couple of inches of bolt shank will have dropped out! I should point out that I have probably increased the risk of failure by using rose jointed dampers which do not spread the damper load across the full width of the aluminium spacer which fits inside the damper bush, so if you run O/E dampers you will very likley not be at risk, but many of you I know also use rose jointed damper setups, so if your car falls into that category its especially important to check! The bolt which failed was new in Feb 1999. Fat Arn Visit the K2 RUM siteid=red> See the Lotus Seven Club 4 Counties Area Website hereid=green> Link to comment Share on other sites More sharing options...
metal mickey Posted April 21, 2002 Share Posted April 21, 2002 Arnie, I don't know the rose jointed shocker set up you describe but can you have it altered to allow fitment of a bush to spread the load ? Say fit a larger i.d joint in the bottom with a bush inserted into it. Mike. Link to comment Share on other sites More sharing options...
EFA Posted April 21, 2002 Author Share Posted April 21, 2002 It already has a 1/2" ally bush over a 3/16 bolt. Guess a steel bush may be the way forward if it occurs again. I have a conical spacer and a couple of packing washers each side of the rose joint to prevent the rose joint fouling. Fat Arn Visit the K2 RUM siteid=red> See the Lotus Seven Club 4 Counties Area Website hereid=green> Link to comment Share on other sites More sharing options...
Paul D Jones Posted April 21, 2002 Share Posted April 21, 2002 Arnie It already has a 1/2" ally bush over a 3/16 bolt. Is that correct 3/16 bolt for the wish bone to damper? Sounds a bit small. Paul. See My Car Here Link to comment Share on other sites More sharing options...
EFA Posted April 21, 2002 Author Share Posted April 21, 2002 Paul, I think its 3/16 9without checking the manual) Whatever, it was the std alloy bush and the std bolt. All new Feb 1999 Fat Arn Visit the K2 RUM siteid=red> See the Lotus Seven Club 4 Counties Area Website hereid=green> Link to comment Share on other sites More sharing options...
elie boone Posted April 21, 2002 Share Posted April 21, 2002 Arnie, While running a check up on a K series (115bhp) before a track day i discovered that the lower bolt on the lh side was about 1/2 inch loose. Maybe it is an other spot to keep an eye on like the rh radius arm at the rear. Link to comment Share on other sites More sharing options...
Coose Posted April 21, 2002 Share Posted April 21, 2002 3/16" = 4.8mm..... Surely shome mishtake??? As Mike said, I would fit a rose-joint with a larger i.d. and thus a bush to suit, going up to a 12mm dia bolt... Also, check the grade of bolt - these MUST be high tensile (can't remember the correct designation...) Cooooose Link to comment Share on other sites More sharing options...
sjwb Posted April 21, 2002 Share Posted April 21, 2002 I thought it was 5/16th in old money. Anyway, I wondered if the constant hammering of the rose joint on the bolt has caused stress related fracture(s) which has become a catastrophic failure. The standard bushes (being isolators) almost certainly protect the fixing from any such shock loads. There is of course the chance of a faulty bolt. Unbrako? As an afterthought, perhaps a 3/8" fixing would be more appropriate and do renew all the other fixings as I am sure you will. Steve B Link to comment Share on other sites More sharing options...
captain chaos Posted April 21, 2002 Share Posted April 21, 2002 I've got the same set up as Arnie and I have to say these bolts were worrying me BEFORE Arnie's posting. I think a steel bush might help but even though the shank of these bolts is 7.8mm it still makes me nervous! Link to comment Share on other sites More sharing options...
EFA Posted April 21, 2002 Author Share Posted April 21, 2002 Yes they are 5/16ths. Sorry for the confusion. I think they have just become an anual service replacement part. I'm not sure its that simple to change to a 3/8 bolt as the head size would also change..... Fat Arn Visit the K2 RUM siteid=red> See the Lotus Seven Club 4 Counties Area Website hereid=green> Link to comment Share on other sites More sharing options...
edmandsd Posted April 22, 2002 Share Posted April 22, 2002 It was for this reason HTR fabricated my wide track front suspension around the trunnions Arnie. They weren't comfortable with the loadings on the bottom of the dampers with the standard set up. Link to comment Share on other sites More sharing options...
Coose Posted April 22, 2002 Share Posted April 22, 2002 Increasing the diameter of the bolts will undoubtedly increase the bolt head size, and thus will probably mean attacking your chassis with a drill, and possibly even mean the manufacture and installation of new mounts. But, after one has snapped already do you really want to take the risk of this happening whilst at full chat? I would certainly recommend going up to 10mm dia whilst still using a bush setup, possibly steel but a decent quality dural would probably suffice. Also, make sure that the bolt is of a higher grade than the standard 8.8, 10.8 being the norm for disc mounting... All suspension mounting bolts on my Striker are 12mm dia. and that is how they'll stay! Obviously, the choice is yours but I'd hate to say I told you so... Coose Ieng AMIIE BBC ITV 32DD Link to comment Share on other sites More sharing options...
AMMO Posted April 22, 2002 Share Posted April 22, 2002 You should be able to get 5/16" bolts in 12.9 from Unbrako / SPS. I would not use 8.8 in this application. 10.9 are a bit of an odd ball, I haven't come across them that often. Most shock bolts are 1/2" or 12 mm. AMMO Link to comment Share on other sites More sharing options...
Morls Posted April 22, 2002 Share Posted April 22, 2002 Cooose, Quoting Wilde or Morrisey is one thing, but...the Hivesquestion.gifsmile.gif Mark Link to comment Share on other sites More sharing options...
Robster Posted April 23, 2002 Share Posted April 23, 2002 I have just ordered Avo spherical bearing rear shocks (the spherical bearing is at the lower end to go onto the live axle)...and am now a bit worried. The bolt on a live axle holds the arms to the chasis from the diff as well as the damper. Not sure what size the bolt is, but it is big..I wasn't planning on using a bush insert as it would mean using a smaller bolt which then wouldn't fit the rest of the parts. Do I need bush inserts? Arnie..glad you posted this thread, if everyone on the site takes 2 mins to look at these critical bolts we would all be a bit safer! Robster Link to comment Share on other sites More sharing options...
EFA Posted April 23, 2002 Author Share Posted April 23, 2002 Robster, The rear bolts are 1/2" dia I think so you will not have a problem. The bolts on the front wishbone of a car without trunnions are much smaller! AMMO, I will be seeking some 12.9 bolts and will post here when I find them..... Umbrako do not have a 12.9 2 3/4 x 5/16 UNF - Its an odd size for a caphead! Fat Arn Visit the K2 RUM siteid=red> See the Lotus Seven Club 4 Counties Area Website hereid=green> Link to comment Share on other sites More sharing options...
AMMO Posted April 23, 2002 Share Posted April 23, 2002 Arnie When I had my workshop in Surbiton I used to use a little shop called Jones Industrial Fasteners. Run by husband and wife team. Very helpful. Managed to get most things I needed. Don't know if they are still there. Number was 0181 390 4818. AMMO Link to comment Share on other sites More sharing options...
sjwb Posted April 23, 2002 Share Posted April 23, 2002 Arnie, If you call Bob Beale at Cromwell Tools on 024 76664614 I think you may well find your bolts. 3" are easier to source but 2 3/4" should not present a problem. Unbrako capheads are all 12.9 grade. Just refer to his recent conversation with Steve Bourne. Steve B Link to comment Share on other sites More sharing options...
EFA Posted April 23, 2002 Author Share Posted April 23, 2002 Unbrako only go to 2.5" in 12.9 They can do a US spec 1960 which is similar strength and these are £140 per box of 100. I'm trying to get the spec of the std bolt from Caterham at the moment, then I'll be trying to find 49 other people with the same problem! Fat Arn Visit the K2 RUM siteid=red> See the Lotus Seven Club 4 Counties Area Website hereid=green> Link to comment Share on other sites More sharing options...
Nick M Posted April 23, 2002 Share Posted April 23, 2002 Arnie, You could try Trident Racing Supplies - 01327 857 822 - or www.tridentracing.co.uk They've come up trumps with all the nuts and bolts I've ever needed. Link to comment Share on other sites More sharing options...
ECR Posted April 23, 2002 Share Posted April 23, 2002 Arnie, another name to phone: Non Standard Socket Screws 0121 523 3211 (a really useful company on occasions !) Link to comment Share on other sites More sharing options...
EFA Posted April 23, 2002 Author Share Posted April 23, 2002 Too bad all, The std bolt is a 12.9! I am hoping this is a recent (post 99) upgrade, and that my old bolt was made in China! Fat Arn Visit the K2 RUM siteid=red> See the Lotus Seven Club 4 Counties Area Website hereid=green> Link to comment Share on other sites More sharing options...
Bilbo Posted April 23, 2002 Share Posted April 23, 2002 Hi Arnie Well having just ordered some it does give me a few concerns. See my posting under "new shockers" on this list. Another place I buy bolts from is Capital Supplies in Croydon its small but very helpful 0208 665 5520. 1988 200 bhp, 146 ft lbs, 1700cc Cosworth BDX with Brooklands and Clamshell wings Q 979 CGY Link to comment Share on other sites More sharing options...
Coose Posted April 25, 2002 Share Posted April 25, 2002 It's obvious - go up to 3/8"! Do you want to die???? eek.gif It may mean chassis mods, but surely its gotta hurt more next time they break when you're diving into the hairpin at Cadwell? I know what I'd rather do.... Link to comment Share on other sites More sharing options...
gramey Posted April 25, 2002 Share Posted April 25, 2002 May be a stupid observation, but I wonder if a 12.9 is too brittle to take the shock loads using a Rose joint. I suspect it's not a load problem, but the higher grade the bolt, the more brittle they are. I would experiment with a lower grade bolt as the shear load capability of a lower grade bolt would probably far exceed the loads it is taking. Any metalurgists out there to call bull***? George Link to comment Share on other sites More sharing options...
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