# Corrosion



## trev1964 (Oct 10, 2018)

Had my car in the air today to swap wheels around and noticed my boot floor is seriously corroded. 
Going to throw it on ramps tomorrow and attack it with a drill and wire brush attachments and then treat with rust remedy. Stonechip it all once treated. 
Dissapointed to say the least though. 9.5 yr old car with low miles and its rusty as fook under there. Dreadful.


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## BlackTipReefShark (Jun 1, 2016)

is it corroded from outside or has water been sitting inside the boot?


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## trev1964 (Oct 10, 2018)

Underneath the car. 
Attacking it tomorrow. 
I'll get some photos. Seriously worried about bursting through the floor. 
I'm hoping its a case of looking worse than it is. It looks fucked. 
Found loads of corroded bolt heads and suspension components etc since buying the car. 
Shocking build quality. Really put me off Audi.


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## r_turner01 (Sep 12, 2018)

What year is the car as mine doesn't have 1 spec. Sounds like it's been exposed to a lot of bad weather


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## trev1964 (Oct 10, 2018)

June 2009 registered. 
Bodywork is ok. 
Underneath isnt though. 
Bolts and fasteners arent either. 
Shocking state for a less than 10 yr old "premium " brand car.


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## Hoggy (May 8, 2002)

Hi Trev, If it is just surface corrosion you'd be better off coating it with Waxoyl or ACF 50. Waxoyl would be my 1st choice.
Hoggy.


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## trev1964 (Oct 10, 2018)

Got flaking paint everywhere and lots of rust. 
Got rust remedy and 2 aerosols of stonechip. 
May throw waxoyl over everything once I've sorted this. 
Gutted to be honest. Had bought this with the intention of keeping it for a few years. 
If i bust through the floor with the wire brush tomorrow, it will be going.


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## Hoggy (May 8, 2002)

Hi trev, My MK1 has hardly ever got wet & yes was surprised at the amount of surface corrosion on suspension & fasteners. Vorsprung durch Technik. :roll: Been sprayed with Waxoyl for a few years now.
I have a 36 year old XR3 with less corrosion on suspension. Also German made.
Hoggy.


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## trev1964 (Oct 10, 2018)

Its been steadily getting me down all day. 
Sold a 2006 SLK 350 and bought this TT. 
Wasn't a spot of rust under the SLK. 
Just fancied a change. Was a toss up between the TT and a Boxster, owned one before, should have bought the Porsche. 
I am hoping i rescue it tomorrow. 
Fingers crossed.


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## happychappy (Feb 9, 2015)

I would be interested to see your photos of the corrosion as I am working my way (slowly) cleaning/inspecting from front to rear and am surprised at how good my car is!

Yes some of the bolts are corroded on the head and also some of the self tapping screws are a little worse for wear, but a quick whizz over on the wire wheel attached to bench grinder, a couple of coats of paint and all is well.

Must be honest, the wheels were a bugger to get off, but I am generally pleased with the condition under the car, especially after using a steam cleaner underneath the chassis, it looks like new!

I have yet to get to the rear, but have noticed that the subframe is not great, that is my next winters job - subframe off, respray/powdercoat and reassembly, might do a quick touch up job on it for this year though.

I am going to take a look at the boot floor when I venture out to the garage this morning, you have me worried!


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## trev1964 (Oct 10, 2018)

I'll get some pics shortly. 
You're not the only one who is worried. 
I've read up and the front end is aluminium, yet the rear is steel..!!
Who thought that was a good idea. 
My subframe is also quite corroded, nothing like as bad as the boot floor though.


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## trev1964 (Oct 10, 2018)

Offside is the worst. Nearside looks just surface corrosion. 
Subframe isnt rotten, just rusty.


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## happychappy (Feb 9, 2015)

Wow, that's really not good 

Don't wanna go down to the garage now......


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## Hoggy (May 8, 2002)

Hi Trev, That's really bad, never expected it to be like that. Must have been driven through the tide to be that bad.
Hoggy.


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## tttony (Dec 21, 2014)

Wow, I'm shocked and amazed. It reminds me of Italian cars of the 1970's. Not at all what I would expect of a TT. Even exposure to normal winter road salt shouldn't have had that effect. I can only assume that the car has been subjected to sea flood water.


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## Allspeed (Oct 7, 2016)

Omg!


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## trev1964 (Oct 10, 2018)

Its the only part of the body thats like that. 
Front end is all good, as is the floorpan. 
Ive sorted it out now but I'm not happy.

After wire brush and rust remedy and then primered.


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## trev1964 (Oct 10, 2018)

Now stonechipped.

Ive emptied the boot and checked from inside. Its like new. All external corrosion. Garbage build quality. 
My first ever Audi, also my last. 
Its not even an old car, 9.5 yrs old. 76k miles with a full service history up to 75k. 
Really annoyed with it. 
Got to calm down....


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## tttony (Dec 21, 2014)

That extent of rust is not normal. I assume that you have not owned the car from new. At some point in its life it has been exposed to something abnormal such as driving through deep salty floodwater or along a long stretch of damp beach.


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## Stiff (Jun 15, 2015)

tttony said:


> That extent of rust is not normal. I assume that you have not owned the car from new. At some point in its life it has been exposed to something abnormal such as driving through deep salty floodwater or along a long stretch of damp beach.


Totally agree. That's not your average rust for a that age of Audi. Mine is the same age with twice the milage and is nothing like that at all and I think you'd be hard pushed to find anyone on here with a MK2 in a similar state.
With that in mind, I wouldn't let this one-off put you off the Audi brand completely - you could well have bought a Boxter that had been treated similarly and be cursing Stuttgart. Someone somewhere _will_ be, I imagine. There's good and bad in every make and model.
Chin up now though, looks like you've done a good and thorough job. Nice work.


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## Allspeed (Oct 7, 2016)

Indeed, my Nephew was considering a TT, but opted for a low mileage mint Boxster instead with full Porsche history.
Fast forward two years. The Porsche needed expensive engine repair with a ceramic bore issue.

He should have gone with the TT.

Now part exchanged un repaired for an Alfa 4c

Anyway O.p. Your efforts should do the trick for you.
Are you in the Highlands?


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## Hoggy (May 8, 2002)

Hi, Looking much better hidden, but if you intend keeping it, spray Waxoyl or ACF 15 into those box sections, as probably corroding inside as well.
Hoggy.


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## SwissJetPilot (Apr 27, 2014)

It really looks like the car stood in salt water for an extended period. I was in Bosham some years ago and I had to run out and move the car when the pub owner told me the tide was coming in. He had pictures on the walls of quite a few people's cars that ended in knee deep sea water.


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## trev1964 (Oct 10, 2018)

Thanks everyone. Good advice to throw waxoyl in the cavities. 
I'll do that. 
I'm confident I've stopped it in its tracks for now. 
I'll get some waxoyl ordered now.


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## trev1964 (Oct 10, 2018)

Ordered 4 x 500 ml cans of cavity wax and a 360 degree hose to get it in the nooks and crannys. 
I'll get it done next Sunday. 
Aiming to do all the box sections on the car and into any access holes i can find. 
If i do it all front to back, it should last the distance. 
Been many years since i chased rust on a car.


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## r_turner01 (Sep 12, 2018)

That is shocking i have to say, mine is brand new underneath but also never exposed to any form of winter.

Done 20 miles today to blow the cobwebs out as it was bone dry here, back back in the garage now as evening coming.

It reminds me very much of my previous MX5, was a 2006 and totally rust free, underneath was solid but my friend also bought a 2006, same colour, and very similar age, but his looked like a boat underneath compared to mine, appeared his had spent time in salty water where as mine was garaged, nothing to do with build quality, but quality of care of previous owner.

I also had the whole car sealed underneath, I will at some point do same with this as its good practice, seems like you have got a grip of the situation and now can relax


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## grantlack (Aug 3, 2017)

I see undercarriages like this all the time in the midwestern US. mine isn't great either, but not quite this bad- mostly confined to the bolts, subframe, and maybe one spot on the body itself. typically that's a byproduct of long winters, aggressive road salting, and outdoor storage, but the first two seem unlikely contributors for your lot. waiting for my rear suspension nut/bolt order to be fulfilled, and replacing all my rusty hardware after this winter is up.


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## TT-driver (Sep 14, 2010)

On mine it wasn't as badly rusted as seen on the posted pictures. But that's because I applied anti rust spray wax a couple of years ago. There were at least 30 spots of rust on an otherwise perfectly clean surface. Even hand cleaning the underside of the car annually couldn't prevent this rust.
But one has to be aware: this area of the car is steel. And it's literally only covered in primer. In a hybrid aluminium/steel construction the steel part is always more susceptible to rust. The bottom of the TT being perfect proof of that.

Anyone who wants to keep his or her TT pristine needs to add a couple of layers of paint to properly protect this steel section. In those cases I prefer paint. It doesn't hide anything, is easier to clean and looks factory original when done right. Also should any rust develop it's visible. Underbody coating may hide rust until the point where rust has perforated the metal.


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## pdk42 (Apr 23, 2018)

Crikey - I'm afraid to look at mine now!


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## happychappy (Feb 9, 2015)

Just got in from the garage and it's not brilliant news. :x

It's nowhere as near as bad as the OPs car, but it's worse than I thought.

I will spruce it up this year, but next year the subframe is coming off for a total refurb.

Why on earth did Audi make such a great job of the front end and neglect the rear?

Is it a weight/balance thing?


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## trev1964 (Oct 10, 2018)

It's a definite weak spot i think. 
Steel with hardly any protection. 
Thing is, if you have no reason to go under there, you could easily miss it. 
I only noticed it cos i was swapping front wheels to back and was under there with trolley jack and axle stand.


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## happychappy (Feb 9, 2015)

Totally agree, I could see that a couple of parts were a bit groggy when I removed the rear wheels.

It's only since I went under it this morning that I realised it was worse than I initially thought.

It's nothing that can't be sorted out, but if you want to do it properly it's not a roadside job.

Maybe this problem could be added to one of the buyers guides?


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## jokskilove (Sep 10, 2013)

Should be part of any generic buyers guide to get down low and have a look under the car, regardless of age.

I got mine in mint condition and got it rust protected right away. Danish roads are really unforgiving in winter - aggressive use of salt, and wet climate.

5 winters later, it's still doing alright. The exhaust looks decent, but the part holding the rear muffler together with the rest of the ehxaust had rusted away, so had to replace that.


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## happychappy (Feb 9, 2015)

Problem is with the rear is it's hard to see where the corrosion is unless it's up in the air and if the front has been inspected first this will lead to a false sense of security.


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## Xcession (Nov 15, 2018)

Whoa Trev - just seen your original pictures - that looks awful mate  Like others, I'm kinda scared to check my own now, but think I'll have to inspect it sooner rather than later having seen that! Having said that, looks like you've done a fantastic job in treating it - hope all will be good from now on!


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## grantlack (Aug 3, 2017)

I think the aerodynamics of the underbody, coupled with the fairly open rear wheel wells, are heavily to blame- that and obviously the lack of appropriate preventative treatment. while the front of the underbody is really nice and flat all the way back to the fuel tanks, that all goes out the window at the rear subframe. no doubt there's a good bit of turbulence carrying salt and water up into the offending areas. on a day with particularly heavy freezing rain, I even had my rear sway bar completely iced into place and unable to move. rear end was all over the place, it was terrifying.


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## TT-driver (Sep 14, 2010)

Think you're partly right there. Additionally the layer of primer is even too thin to properly cover the spot welds. Also while welding sparks will contaminate the surface. If these aren't covered properly, these sharp particles will stick out of the primer like an ice berg sticks out of the sea. The top of these particles will start rusting the day the car leaves the factory.

And while the metal is zinc protected, the zinc oxidises first. Once that starts, the primer around such a particle can simply be wiped off!


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## Iceblue (Jul 20, 2018)

@ Happy Chappy - Yes. Aluminium at the front incl bonnet and doors to reduce addittional weight and distribution of a fundamentally front wheel drive vehicle. Lucky it was not a Golf as the whole frame may have been rusted out.

Amazing the corrosive effects of salt which fortunately is not required on the roads in Oz. Mine is 09 (83,000 kms) and had a good look underneath at the last service and tyre change and could not see any rust except on wheel hubs and horizontal side of discs which is annoying as you can see this through the alloys.


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## grantlack (Aug 3, 2017)

Iceblue said:


> @ Happy Chappy - Yes. Aluminium at the front incl bonnet and doors to reduce addittional weight and distribution of a fundamentally front wheel drive vehicle.


not quite. doors are steel, as is the bootlid.


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## happychappy (Feb 9, 2015)

You would think that seeing as the car is designed by a European team (I assume?) in a European country that has the southernmost side of its country visited by snow and ice which results in salted roads for a good portion of their winter that corrosion protection was high on their list.

As I have already mentioned the front end is amazing, so why not do the same at the rear?

I understand that boot/doors are made of steel to try to achieve 50/50 balance, but these are on show and corrosion would be easily spotted so that's not a problem, but to use steel on the underside of the boot in any area is surely a step backwards?


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## TT-driver (Sep 14, 2010)

It's like the TT engineers never had winter in mind while developing the TT. Frozen solid windows of the doors being another point in case.

During the winter the TT should be tucked away under a blanket with a thermometer stuck into the grille.

The Q5 should be out there conquering winter wonder land!


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## tttony (Dec 21, 2014)

I have just put on my winter wheels (we've not had any frost here on the south coast yet!). I had a good look under the rear of the car (ten plus years old now) and there is no sign of any corrosion of the sort that the OP has. I am convinced that his car has been exposed to high levels of salt at some point such as driving through deep marine floodwater.


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## happychappy (Feb 9, 2015)

I'm not so sure about the car being used as a boat, but I wouldn't rule it out 

A friends late MK1 is terrible underneath and it's very minty in all other places, I think I am right saying that the MK1s had no alloy in the bodywork?

My car is similar,not quite as bad, but I haven't been all over the back like I have the front yet.

One thing that is bugging me is the rear subframe, thats gotta be done next year, I will tart it up for now.


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