As per the title, but not on a MK3 Fabia but a 2015 6C VW Polo 1.2TSI - which will be identical to a MK3 Fabia in the area of the support frame bolts.

 

The bolt nearest the ARB mounting clamp on the near side failed, with I think is due to road spray including road salt getting in behind/above the collared bolt head and causing the bolt shank to corrode/waist until the bolt head popped off - and ended up on my garage floor!

 

I can't say when this happened as the sheared face of the bolt remains and the bolt head are heavily rusted across - but the "upper" surface of the collared bolt, ie the face that was in contact with the support frame metalwork is about 80% shiny metal, well maybe less than 80% as the rust is obviously covering what was the over sized bolt hole in the support frame and slight rusting is evident from the outer edge of the collar on the bolt head, but then there is a clean area all the way round the collar - I'm including that point as it seems that this bolt head has ended up closing off any chance of accumulated water getting thrown up onto this bolt, draining back out again.

 

(I had a similar type of thing happen with my old 1991 VX Cav GSI 4X4, but on it, it was the ARM link that failed or its fixing nut and part of the threaded end parted company with the rest of the ARB link - in that case, road spray was able to get in from under the rubbers and stay trapped in the oversized hole in maybe the track control arm instead of draining back out.)

 

I'll be letting my trusted VW Group Indie take care of that as they might manage to weld a bolt/nut to the end of that bolt and get it out, if not the support frame will need to get dropped and the car given a 4 wheel realignment, very annoying.

 

I've not known that to happen to the late 2009 SEAT Ibiza of my wife's old 2002 VW Polo over the time that we had them, 10 and 13 years respectively - but having said that, I would not have been any the wiser until I had looked under this 2015 VW Polo - the rusty bolt head on the garage floor was the clue today!

 

Maybe "check your bolts"!

Pics?

Here is a pic!

 

Thanks. 

How bizarre.

Looks like that broke ages ago and the bolt head has just been sticking there with corrosion debris?

I guess there are 3 other similar bolts to remove/inspect? The symmetrically opposite one on t'other side especially.

Items 6, 4 here? LLLParts

This is something that VW need alerted to if they are not already. 

Their people will have to speak to other people and do inspections and tests and maybe decide it is one of those things and happens on 7 year old cars.

 

Or they might need to issue a TPI, inform Authorities in countries such as Germany, even the UK and start a Service Campaign, Recall Actions or whatever. 

56 minutes ago, Pete_Ex-Wino said:

Thanks. 

How bizarre.

Looks like that broke ages ago and the bolt head has just been sticking there with corrosion debris?

I guess there are 3 other similar bolts to remove/inspect? The symmetrically opposite one on t'other side especially.

Items 6, 4 here? LLLParts

As normal for me, bad timing, younger daughter  and her hubby have come up from London for Easter so my car will need to get used, plus my local VW Group Indie is not answering his phone, so I'm guessing not open for a few days.

 

At least local VW dealer parts department is open so I've taken the worst case situation and ordered in items, 3, 4, 6, 12 and 13.

 

I'd think that it will be only the one on the other side, if it is similarly "boxed in" will also be rusting badly, but just in case the subframe needs lowering, I've prepared for that - I think!

 

I've forgotten how similar the subframe on the 9N and the late 2009 Ibiza is to this 2015 Polo, in case it is a possibility on these models, to be frank, if that bolt had not turned up on the garage floor, I'd be still driving that car around, maybe, just maybe that bolt shank having been expanded due to heavy rusting, is what is stopping the subframe from moving or flexing, everything seems fine when driving that car.

49 minutes ago, roottoot said:

This is something that VW need alerted to if they are not already. 

Their people will have to speak to other people and do inspections and tests and maybe decide it is one of those things and happens on 7 year old cars.

 

Or they might need to issue a TPI, inform Authorities in countries such as Germany, even the UK and start a Service Campaign, Recall Actions or whatever. 

You would like to think so, but "out of warranty = out of our hands" seems to be plan.

Not globally.  I still get a Recall notice annually for a 2009 Suzuki Jimmy manual brake bolt issue.   Oddly it was an Automatic I had.    You only know how things might fail after 5 years when 5 years have passed. 

The bolt was overtightened to beyond the elastic limit and the corrosion gradually has done the rest.

 

Probably by a mechanic (you really have to heave on them) who would have felt the yield and stopped before shearing it right off, or it could have been an incorrectly hardened bolt from the initial assembly line.

 

The remaining shaft will unscrew easily, getting a purchase on it will be the hard thing, welding a nut on the probably solution.

I doubt anyone's touched that since build day? 

7 hours ago, J.R. said:

The bolt was overtightened to beyond the elastic limit and the corrosion gradually has done the rest.

 

Probably by a mechanic (you really have to heave on them) who would have felt the yield and stopped before shearing it right off, or it could have been an incorrectly hardened bolt from the initial assembly line.

 

The remaining shaft will unscrew easily, getting a purchase on it will be the hard thing, welding a nut on the probably solution.

If that has had been overtightened, it could only have happened at initial assembly in South Africa, and like the "popping off" high pressure fuel rail screws on the 1.2TSI and 1.4TSI engines, it should have happened to quite a few cars over a period in time.

 

If I'm correct on how/why it corroded so much, I'm guessing that the threaded section and its captive nut will also be rusted up to bug--y and will not be willing just to unscrew, so yes, nut welding on as a minimum, lowering subframe maybe - and that might bring with it some other bolts not being exactly willing to come out with their heads still on, and that is my concern.

Edited 15 April, 20224 yr by rum4mo
Spelling!!!!

My local VW Group Indie has now re-opened for business after Easter break, so car is booked in for 28th April.

Car has now been sorted out, ie all bolts replaced and returned to me and 4 wheel geometry checked and adjusted, the camber on the RHS was at its limit of -58' and the toe'ng was well out LHS +21' and RHS -23' - which would be what has caused a bit of uneven wear across the front directional winter tyres and making them a bit noisy, hopefully that and not a wheel bearing(s) issue, swopping over to summer times soon will prove/disprove that theory!

 

The front bolt from the other side has quite a bit of surface rust but not rusted deeply into the bolt shank as the sheared had, this bolt was still wet when I collected the car 3 hours after it had been worked on and the rusting is quite far up that bolt, that car has not been out on wet roads since 14th April, so 2 weeks later there is still water in the cavity that is formed by that bolt's head and the subframe metalwork - that is not good!  I'll need to see if I can get Waxoyl or some more creeping rust proofing into that area to try to preserve these new bolts.  The 2 rear bolts look very clean so that area must be okay.

That opposite one doesn't look to have been far behind.  Would be interesting to do a tensile test to failure in its current state and see what it goes at?

Looking like a serious design oversight, isn't it? 

Edit: or just possibly an assembly time error if there was supposed to be a load of waxoil-type stuff squirted in there.

 

Edited 28 April, 20224 yr by Pete_Ex-Wino
Alternative thought

I've been told that these front bolts being wet is "normal" and sometimes, I suppose due to location, water sometimes runs out when these 2 front bolts are removed, and this has been like this over several generations of VAG cars, which sounds like someone missed a trick when designing that area. Though if very few of these bolts actually fail, then maybe I'm just unlucky - but annoyed!

 

I'll aim to get some anti rust fluid down into that area, just how successful I end up being, remains to be seen!

 

One way could be to buy another 4 new bolts, pump in plenty Waxoyl from below, fit the new bolt and torque + angle, then give the bolt head a long slow heat up to flow the Waxoyl back down around the bolt, repeat on the other side.

 

Edit:- part of that plan would be to attempt to keep Waxoyl off the top end of the bolt thread as if that ended up on the section of the bolt that passes into the "nut" then that would mess up the end load on the bolt head.

Edited 28 April, 20224 yr by rum4mo