CSR owners check your rear suspension mounts

[SamC]

+ Eckles

[David aka Blue7]

#125 Amended to add Eccles

[Brian T]

My car's rear suspension was disassembled and reset at BOSS racing, who I'm certain would have identified suspension mount issues, so I feel reasonably comfortable that my CSR 260 is currently OK. 

But I'm definitely going to keep checking. 

[Gareth H]

Brian, I wouldn't take the risk, mine had a visual inspection a few hundred miles before failure, the potential consequences  are not worth risking for a relatively low cost fix

[David aka Blue7]

I have just collected my car from the Garage having had both clevis brackets replaced and as can be seen in the photos there seems to be no damage to the nearside clevis, YET.  I was told that the vertical studs and the other 4 bolts were removed quite easily but the damper bolts were a bast**d!

I have contacted Mike Calvert to ask if he is agreeable to publishing an article in LF, attributing no blame but just highlighting the problem, explaining how the clevis brackets are replaced and where to source the parts and of course encouraging CSR owners to replace both clevises ASAP.  Not many members visit Tech Talk but they all receive a copy of and read LF and personally I think we would be failing in our duty as a Club if we did not highlight this problem to members.

I will have a go at drafting the article if the Club agrees.

David

[MarkTheGoose]

Good news update! DVSA dialogue with Caterham has led to the following request to me from DVSA:

------------------------------------

The manufacturer has asked if you still have the failed components and if they can have them for further analysis.

If you do have the failed components and are prepared to allow this, it will be more beneficial to use direct contact through the manufacturer. To do this I will need your permission to forward your contact details, usually email and phone number so they can arrange it directly with you. 

Please advise by return.

Please note, further analysis is likely to lead to destruction and it may not be possible to return the components. If you want the components returned, you should discuss this with the manufacturer beforehand.

------------------------------------

I'm 90% sure that I don't have my clevises anymore. Does anyone else still have failed parts that they would be prepared to share with Caterham for analysis? I've made the observation that to remove the wishbone pin, that the parts will have been heat-cycled to break the Loctite seal between the pin and the clevis - not sure how this affects the metallurgy?

I've shared the three threads on here with DVSA too, so I assume/hope that Caterham will now be reading these too.

[ScottR400D]

I'm not sure there's much good news there and I can't imagine how examining broken components of that nature would lead to their destruction, let alone be likely, unless one wanted it to. 
 

 

[David aka Blue7]

Interesting reply Mark, I wonder if Gareth and Sam C have received similar replies from DVSA, in which case they will definitely have the failed clevis to provide CC with.

I haven't contacted DVSA but I have been in contact with Bob Laishley who advises that he is investigating and will reply in due course once he has more information.  I still have my failed clevis which I would gladly supply if Bob requests me to do so although I think CC should pay P&P.

I agree with what you say in #121 in that CC should make the effort to contact all CSR purchasers and contact their Agents to alert them to the problem when they come to service or buy / sell a CSR.  It is totally ridiculous that CC would not supply a clevis unless you ordered at least 10 but in hindsight you would just be buying 10 of the same design that are failing, unless Titan have redesigned their Clevises?  Which  brings us back to the 485, are CC / Titan still fitting this same clevis to their new cars?

David

 

[SamC]

I've been contacted by the DVSA and have supplied all my information including microscope images of fracture surfaces etc. Frustratingly I binned the broken clevises after I replaced them.

A proper analysis will involve destroying the bracket as you'll need to cut the component up to see if there are sub surface fractures, corrosion pits etc. You can only tell so much from the surface. I shouldn't imagine that's a problem though for anyone that has recently removed them.

Definitely worth letting them know how you've managed to get the wishbone stud out though as heat could affect some of the properties they will be looking for such as hardness. I removed mine by heating them to 200deg in an oven, anyone using a gas torch will have been a bit hotter and less controlled.

[Gareth H]

I've been contacted too, still have mine, so will forward them to Caterham when they contact me.

[David aka Blue7]

Update on my situation is that after discussion with Bob Laishley and CC Chief Engineer, CC are sending a Courier to collect my clevises, hopefully tests will establish the cause of the fractures. 

As an aside, when cleaning up the broken clevis, the thickness of metal on the broken section looks thinner than that on the intact section but it may have been drilled to a wider diameter for the bush, see photo below.

David

[SamC]

David, the difference in thickness is due to the bottoming bush and the nut locating on that side. 
 

All failures I've seen have been on the bolt head side.

[David aka Blue7]

Sam that is interesting because that was the offside clevis and the bolt head was indeed on that side.

[MarkTheGoose]

Mine was the nearside clevis, front and I'm pretty sure that was the bolt head end...

[SamC]

It's part of the compounding evidence towards the stress corrosion cracking cause.

Whilst the lug area is slightly bigger on the nut end due to the extra material, it's not a massive % difference. There have been quite a few cars - mine included - that have survived a period of time with the bolt head end failed and only the nut end secure. That implies that the lug strength alone is more than sufficient (how would a component now bearing twice the load it was designed to, plus a chunk of bending due to the other side failing, not fail immediately?) By hand calc, both the lug sizes and therefore strength appears more than sufficient.

The main difference between the two sides is one has a permanent hoop stress imparted on it, the other doesn't. My lug had very small corrosion indications on it which I appear to have weakened the bracket sufficiently for that side to fail well below it's designed load.

Bit of background below for those interested. Main point is that the permanent stress than needs to be applied to a material is often extremely small (sometimes <1/4) compared to it's yield stress. Geekily, it is pretty interesting!

http://www.totalmateria.com/Article17.htm

[David aka Blue7]

Update to say that CC now have both of my clevises the intact one as well as the broken one, I will update further with any feedback from CC.

As I have stated before, only a small proportion of members seem to visit BC but every member has a copy of LF.  I have therefore written a brief technical article for LF explaining the problem, indicating where the clevis brackets are located, where to source replacements, how to replace and urging owners to replace or at least check the brackets as a matter of urgency.  Mike has proof read it and I made a few changes and hopefully it will appear next or the following month.

Other than that I don't know what else can be done to alert CSR owners, there are 9 listed on PH at present, they all seem to be Trade.  Ideally it needs CC to contact all their official Retailers to alert them to the problem but even then there are other specialist retailers, some of which advertise in LF, that will be unaware of the problem.

David

 

[The Chair]

STOP PRESS - For your information:

Please head to the 'News' Section of the Caterham website where you will find the latest information from Caterham on this issue.

There will also be an article and news item in this month's Lowflying magazine which you should be receiving over the next few days.

[SamC]

Link to the above.

https://caterhamcars.com/en/news/calling-all-csr-owners

[SamC]

Incidentally, it is pretty disingenuous of Caterham to suggest it is the same as a spring breaking and not dangerous.  A spring breaking drops the car onto its bump stops. The failure mode of this I much worse in most cases.

[David aka Blue7]

#142 Thanks for the heads up on this Richard

#144 Yes Sam, I was surprised at that statement by CC but at least they have decided to publicise the matter and as I suspected, the same brackets are still being fitted to the 485's

David

[ScottR400D]

Shouldn't they be following some industry standard recall/tech bulletin procedure? 

[Geoff Brown]

All CSR owners who have suffered failure should record said failure(s) with the DVSA.

Vehicle recalls and faults: Report a serious safety defect - GOV.UK (www.gov.uk)

To quote the reporting site:

What counts as a serious safety defect

A serious safety defect is something:

• about the way the vehicle is designed or made that’s likely to cause injury or death
• that happens suddenly and without warning

So, If the defect cannot be detected during routine maintenance or servicing then this is the way to go.

[Jonathan Kay]

From another thread:

Now some Caterham news 

Caterham info CSR(link is external)

inspection guide(link is external)

registration sheet

Jonathan

[David aka Blue7]

Achtung Jonathan, das Registrierungsblatt ist deutsch!

English registration sheet

David

[Geoff Brown]

As the lower damper mount is alloy I am surprised that CC have not recommended utilising a crack detection spray.

From experience on very similar load bearing components on aircraft it is not necessarily so that cracks will show with visual inspection under a bright light. Also the start of or propagation of fine cracks can be mistaken for wear & tear scratching as commented on in the CC inspection instruction.

If I was a CSR owner I would be investing in a spray can of crack detection fluid just to be on the safe side. Just Google 'crack detection fluid/spray'. Average seems to be about a fiver but there are some expensive ones on sale.