90 20v Sill Corrosion

[Obli]

Hi folks,

I'm usually active on the Classic Audi forums. Sone of you may know me from there. Been starting to read here too lately as there are fellow 7A owners here. I hope it's okay to post about mine here? Embarrassingly, I've come begging as the Classic Audi forums are down (historically, it's stayed that way until the end of the month).

I posted the following on Facebook (Classic Audi) too.

---

I've spent a few days a week this past 6 months on my 90 20v getting it started, moved, running well and usable. It's been SORN for 9 years, didn't move for 5.5. I've been focusing on getting it roadworthy and nice to drive/use, rather than the cosmetics (for now). Been a steep learning curve but thanks to the community, a few manuals and lots of time, I'm getting there...

Id like to put it in for an MOT but I'm really worried about the corrosion on the passenger (UK) side at the front of the rear wheel arch. In addition to the holes in the sill end plate, there are holes around the trailing arm bush / bolt nut.

Has anyone had a similar issue with theirs and any idea where to go to get the repair done properly? Methinks this is going to be a big, expensive job. Eeek!



In more positive news, I've managed to make the subframe look a little more presentable for the MOT with a bit of wire brushing and Fertan treatment! Pics below after rinse off of Fertan and then after it dried. No paint applied yet.

[John.]

Yes CA down again !

I bought a 90 quattro a number of years back (unseen) and it was poor then, to be honest I was very disappointed as I'd hoped to get it back on the road but it would of taken my money and someone's skill and time to sort out (it was cheep and so it got stripped for bits)......if I'd kept a hold of it it'd probably look like what you're faced with now ?
That's a big job and one that should only be taken on by someone who knows what they're doing, it's a structural area and it's critical that the rear beam bolts end up in the same place !
I'm sure you already know this though.
Given that the car means a lot to you I'd be careful where you go for repair, almost to the extent that you'd be better to consider the most expensive quotes first because they're the one's that are likely (but not for sure?!) to do the job right first time.
There was a guy on CA who'd had a similar repair done to his B2 coupe ??....might be worth finding out who done it?

[Tractor Dave]

Ashley Grant in Banbury is very good. He did an amazing job on my Ur.

https://www.acgrant.co.uk

[K Simmonds]

Iot's of 7A owners on here James, good to see you posting.

As above that's a quite tricky bit of welding and highly structural, no way that'll pass an MOT currently and regardless it need's dealing with sooner rather than later. It's a time consuming job as the rear axle and trailing arm will need to be removed to get decent access and then the bodywork itself is difficult and must be done correctly, it's critical that the mounting point ends up in the same place.

The guy Dave recommends is really good from the photo's I've seen of his UR.

Jim the guy I work with could also do it properly but pinning him down time wise is hard as he's fully booked up for months, a couple of garages have closed around here recently and it's hard to get a slot anywhere even for basic jobs. I honestly think it would be next year before he could tackle that, it's a couple of days work on a lift. The thing with rust like that is there will always be more work than you can see once it's stripped down, not an easy fix to be honest, though perfectly doable.

What's the other side like?

[Obli]

Hi Kit Thanks (all) for your input, always much appreciated.

The other side looks a bit better, might be OK for now but there's similar corrosion although less developed and it will need attending to, ultimately.

Love the car so going to have to take this one on the chin and get it done properly. There are a few local places I need to speak to, one that's already familiar with the issue - they've done one already (Martin Pollard, Frampton, Glos). I'm wondering if it might save money in the long run by getting both sides done at the same time, what with parts removed. It's probably only a matter of time until the other side goes. Really though it needs someone experienced to take a good look all over.

Geometry considerations aside, I wonder how long I could expect such a repair to last. Be nice to get 10 years out of it. One place I spoke to said it could be £1500-2000 as worst case scenario but said it's considered done then, as in you won't have to worry about it again. Don't think he realises I want to keep the car another 30+ years!

Like you Kit, this car is (hopefully!) a lifer

[K Simmonds]

£1500-2000K sounds about right to be honest as it is a lot of work, it may even cost a bit more to do both sides, but once done you shouldn't have to worry about it again.

A fair chunk of the cost will be in the labour removing and reinstalling the the axle, then doing wheel alignment etc so if the other side is at questionable get it done, though it could be savable, as you say it needs someone experienced to have a look at it. The car needs to be on a lift to assess it properly and really with the axle off and a bit of time spent exposing all the rust. It's one of those job's that's pretty much impossible to price accurately until a start has been made. Probably find there's brake flexi's and solid lines that want replacing and you may as well get the rear axle bushes done as well whilst it's off, their on borrowed time now anyway and you won't get a better chance.

If done properly and finished correctly with paint, seam sealer, underseal then Waxoil injected/sprayed into the sill as well everywhere else it should last indefinitely. You'll almost certainly have to deal with rust somewhere else before that needs any attention again, what's the rest of the underside like, any other spots where's there's significant corrosion?

It's such a rare car that at some point I dare say it's value will catch up with the cost of restoration, though if your like me and keeping it for life that doesn't really matter.

[Obli]

Thank you for your thoughts Kit.

The rest of the underside looks ok to my untrained eye, apart from the fuel pump carrier. There are spots of bubbling coming though around the top of the rear window and on one of the A pillars. The area around the engine bay beneath the brake master cylinder / inside wheel arch is corroded quite badly.

I seem to remember Audi saying that the galvanised body corrodes 5-10 times slower. I'm going to have to keep on top of it as best I can and then she can rot with me in my grave!

Still, they don't make them like this anymore so it's a keeper. Utter madness to others, but new stuff does absolutely nothing for me. Too sanitised. Audi were doing it right in the 80s and 90s. The value of the car to others doesn't matter to me much. It's definitely underappreciated and forgotten. But it's worth a lot to me so the money doesn't matter

[K Simmonds]

No problem, wish I was in a position to take on the work.

I don't have to charge as much as most garages as I don't have may overheads and I work at my own pace and just charge what I thinks fair.

However I haven't got a lift yet and to be honest even if I had, that's actually a bit beyond my skill level. I could certainly do it, but there's people with much more experience than me and that need's to be done really tidily.

Jump on any corrosion you can find before the car see's the road, especially bloody salt. The drivers side chassis leg and wheel arch always seem to be a bit crusty, I think it's the heat from the exhaust. The fuel pump carriers are nearly always now rotten on B2/3 cars, though that's fairly easy to fix, the one on my 80 has dissolved and I'm simply going to make a new one from scratch.

If you can find B5Nuts thread, he goes into detail will how to deal with surface corrosion in this area properly, it's a good read regardless.

I don't think it's madness at all, modern cars are soulless box's built down to a cost and a complete pig to work on as a rule if they require anything other than basic maintenance.