Track day roll bar woes

[krisfl]

Evening.

I'm failing to fit a new FIA/Track day roll bar (cross type) to a 2014/15 S3 metric chassis.

I had the car jacked, shocks off and the standard bar off in about 30mins including tea slurps... 9hrs later... the F'ing IA bar is still not bolted home. I"ve had all the usual fun described on other threads with straps, helping hands and much swearing.

I"ve eventually got the 4 main bolts in finger tight as well as the 5th top 13mm bolt which goes through those wing things. But the last bolt isn't going to line up in a month of Sunday's.

Have a look at the photo... Should I:-

a) Take the Dremel to it... 
b) Call CC parts and ask for another "Precision Laser cut" bar to be sent 
c) Try a pearl of wisdom which someone here might have which will magic away my frustration? 

Ta muchly

 

[L66TEY]

Wish I could help with some words of wisdom, but unfortunately I cant. 
I had mine off to powder coat, but it went straight back on. 

Without second guessing the worst, ie a bent frame - I'd be asking Caterham some questions. 

Hope you get it sorted in time for the pending track day. 

Chris 

[krisfl]

Bent frame???  I hope not. The old bar drops back in perfectly. 
 

ill call CC Parts this am and see...  it's hardly the most technical job in the world, so can't see how I could have lined up the other 5 bolts in such a way that this last one is this far off? 

[Wilts North AR]

Are the bolts now fitted only in by a few threads ?

If so try & pull the roll bar up until stopped by the bolt heads then see if there is enough wiggle room to insert the last bolt. If so then tighten down all bolts a turn at a time until bottomed out.

If not then the roll bar is dimensionally inaccurate. Trouble is that also could be the case with the chassis although 'Westbury' chassis are allegedly built to more accurate tolerances.

Use of Dremel in this case not recommended !

[krisfl]

Thanks. Noted on the dremel! 

The bolts are wound in a little more at the mo. But only wound in with fingers to see where things settle. Easy to have another go. I have tried unwinding a little to give more waggle room and lifting, but so far not enough to get the bolt in without risk of trashing the thread. And I can wind the bolts in smoothly with finger tips. It's just this last little sod! 

 

[Geoff Brown]

That is a mighty large hole for the 'secondary' top bolt which indicates that CC have dialed in some lack of accuracy in manufacture.

I still think that resorting to the Dremel is a bad idea but on reflection it is a 'secondary' bolt hole so could be subject to some adjustment which should be limited to probably not more than 1mm on the offending side of the hole to avoid weakening. 

The other suggestion is assistance to grunt the bar hoping that the tiny bit of distortion may allow the offending bolt to 'drop in'. I have heard of people resorting to strops to distort the bar so all the holes line up.

 

[Jonathan Kay]

"I have heard of people resorting to strops to distort the bar so all the holes line up."

Me too, with the preferred order being to leave the rear legs till last.

"I"ve had all the usual fun described on other threads with straps, helping hands and much swearing."

Is that the order you were trying with the straps?

Jonathan

[krisfl]

Jonathan, yes. The straps helped me to get the main bolts above the shocks in, and in the end, easily threaded running free with just fingers so all good there. And yes I"ve also left the rear legs free, as well as trying to loosely locate with screw drivers. I"ve also tried having a mate lift the whole bar with the main bolts wound in a few turns. But I think that wing plate is just welded on on the wonk. Even If I start that side, and with that bolt, I can't get it to align with the hole...

[krisfl]

Hi Geoff. Yes Straps/strops did help. For this bolt though, the whole bar needs to rotate clockwise about 2mm. Which even with no other bolts in doesn't seem to want to go... It could be me of course! but I like to think I can cope with tasks which are one spanner difficulty on the Haynes manual scale!

[Geoff Brown]

krisfl - I think you have exhausted all alternatives apart from removing the rb & starting again. 
Nuclear option is still the dreaded Dremel.

IMO this is just another example of CC not quality batch testing components from outside suppliers. For all that CC & the customer knows is that the jig for welding up is worn or has become squint over time.

So what do the so called 'build experts' on the line at Dartford do ?  Ignore the poor alignment & just severely grunt to fit? If that is the case so much for defective component reporting & continuous improvement initiatives. But we all know those regimes do not exist any way.

[ScottR400D]

I think Geoff's probably right. A poor quality component allowed to slip through a poor quality system. Shouldn't be too big a surprise. 

I'd  be going right back to CC with it. 

As far as I am aware and certainly the case for me, the only 'persuasion' needed was a little bit on the rear bars not on the bolt holes across the front. 

[krisfl]

Yup rapidly coming to the same conclusion. I think you gents are, sadly, spot on.

I just spoke to CC. They weren't terribly interested, though asked for me to email a photo, which I've done.

However I've had several people now, including a seven specialist tell me that any replacement bar will be the same, but also not to worry about the top bolt too much. Its just there to fill the hole it seems. Or in my case to attach the half hood straps! The integrity and extra strength in the mount comes from the underside bolts, above the shocks. The specialist said its OK to file/dremel so long as the 4 main bolts are OK. But to try grunt again first. So I'll give brut force another go before firing up the angry tools...

Thanks all. I'll share any updates from CC. But not expecting much.

[ScottR400D]

"But not expecting much."

Not a bad starting point. 

[Geoff Brown]

'not to worry about the top bolt too much'  The ONLY bolts that attached previous generations of roll bar to the top of the chassis so they must be relatively important.

Even with later roll bars the bolts still have a purpose in the 'secondary role' - structural integrity, stress management, belt & braces. It is a bit flippant to dismiss them with such a comment.

If they were not required then facility for them would not exist.

Hope you have success with CC about a replacement. Personally I would take the roll bar there, kick down the door & make comparisons/get a replacement. Worth the journey ?

[SLR No.77]

If I'm correct these are the two small M6 bolts outboard of the sockets in the chassis?  Those likely offer very little to the strength/integrity of the bar, in fact full cages don't actually include the plate.  Much more important are the bolts fitted vertically (above the shocks) into the main rollbar tubes, neither of the two cars I've had, had had these bolts fitted ... and one had been used in competition. If you're not going to fit the main bolts though the small ones might offer something!

[Tony P]

I seem to recall, way back when, it was determined (by whom, I cannot remember) that the presence of those two small, outer, setscrews was more to do with a requirement for the number of individual fixings employed, rather than their location or function (for competition accreditation, presumably, when it was said to have FIA approval). They must, obviously, add 'something' to the integrity of the mounting, but how much?

As mentioned above, the oversizing of the hole suggests that some latitude is expected (though I don't think I've seen that much on earlier bars). Unfortunately, given the size of the hole (esp. if you enlarge it a touch) - and that very ugly welding next to it - you may not be able to satisfactorily cover it, and give the head full bearing surface, with a large washer. It seems doubtful, also, that you'd be able to force fit it with the other fastenings in place; and if you could I might be wondering what stresses were being induced in the chassis (that's just a thought mind).

(When I replaced my 'FIA' bar with an Arch-made 'FIA+2' bar - on an Arch-made car - I recall it fitted with very little difficulty at all.)

[krisfl]

Hi Geoff. I can believe  all the strength comes from the chunky bolts which thread in above the shocks,  As having looked at 3 other sevens with the FIA bar fitted only the head of the bolt is touching the plate and not by much. All 3 were all off in different directions. They're not done up that tight either, 20nm ... but this slightly misses the point for me - they should be closer to lining up in this day and age!! 
 

CC have "forwarded my photo to the bar makers for comment"  Teflon shoulders... a Putin style invasion of Dartford may be needed! 

[Geoff Brown]

We can go on about how useful the two top roll bar bolts are but as I stated previously they were the ONLY bolts that attached early generations of bars to the chassis.

In fact ACBC found that the structural stability of the rear end of early Sevens was enhanced by attaching a roll bar utilising the two small top attachment bolts therefore decreasing the amount of rear chassis bar failures.

krisfl - best of luck in your quest with CC. Don't let them go all Teflon shouldered on you.

[CtrMint]

Krisfl I hear your pain.   This was a particular low point during my build.  For hours I thought it impossible to fit, in the end I did manage it, though even now I'm not sure whether by luck. 

The approach that worked for me was to catch only 1 thread underneath on both sides while someone hold the bar, then move the top into place and secure gradually.  From reading your post it does sound like you've got the bottom in so I'm not sure my advice is really that helpful.

It took me an entire day to do mine. 

 

[David Brown]

#19 I would never suggest that it's correct to only fasten a fitting by one thread while adjusting the other end. A definite possibility of stripping the thread. Three or four, while still leaving slack a far better idea. 

[Doc007]

My experience of roll bars, and my trackday cage in particular, would suggest that if you leave it long enough (I found 2yrs to be more than adequate) the rust will enlarge the hole for you and simultaneously lighten the part.