How to fix unsightly, but not terminal, rust?

[philnewmerc]

Hello. My new to me CLS 55 has quite a lot of surface rust on its rear arches on the inner lip. I hope the photo shows this. I've bought some hydrate 80. I wonder if I should just paint this straight on. I don't really want to grind away as the instructions suggest because I don't know if it will end up looking like a complete pig's ear. I am obviously unsure what the inside of the arches looks like because it's behind a plastic liner. I suppose I could get that and the rest of the car wax injected/sprayed. Any suggestions welcome

 

[ALFAitalia]

I don't think you will achieve too much just painting over it.. I find the only way is to grind out as much as possible....then treat it with the chemical...then paint over.....but even then it often comes back if the slightest trace is left behind....

 

[KillerHERTZ]

Needs taking back to bare metal and completely removing the rust, even if you still see black dots after sanding down/treating it will still return.
You want to stop that in its tracks before it becomes much much worse over next winter.

Unusal to see a W219 looking like that.

 

[alabbasi]

With a little bit of chicken wire and a lot of fiberglass, there's no such thing as terminal rust.

Jokes aside, once you strip it, you'll find that it's going to be worse than what you see.

 

[Teego]

My bodyshop fixed that for me. Not a lot of £ as part of a tidy up exercise.
He's an OCDC one man band. Does a lot of work for bikers who are hyper critical.

 

[philnewmerc]

My bodyshop fixed that for me. Not a lot of £ as part of a tidy up exercise.
He's an OCDC one man band. Does a lot of work for bikers who are hyper critical.

Have you a ballpark figure I might expect for a professional to tidy this up on two wings? They seem perfectly solid just unsightly.

I saw a handful of CLS and they all had small amounts of corrosion, but this one was the worst. I bought it because it was low mileage and in otherwise excellent condition, and by far away the cheapest. I think the Scottish climate wasn't kind to its wings and they were packed with mud

 

[Gnasher141]

That looks like a front wing which makes life simpler in the fact there is only one sheet of metal as opposed to rear arches having 2 that are welded together and an inaccessible seam.

Remove wheel to get better access.

Take off the arch liner and clean off all debris.

Grind off all flaking paint until you reach bare metal. (It should be possible to contain to arch lip)if you have any holes or pits, treat with rust treatment.

Any holes (I would imagine these will be small going by pictures) will need to be filled and sanded flush before applying any paint.

Prime the bare metal, then apply paintable spray stone chip resistant paint generously to the inner arch and edge to seal out any water ingress(most important to prevent rapid return of rust)

Paint treated area with basecoat and clear spray paint. A little tip when masking up is to fold tape back on the radius of the edges to prevent a sharp masking up line.

Hope this helps

 

[Petrol Pete]

Phil , there is probably a fair bit more of that dotted around the car , pi$$ poor quality for such 'high end' cars in my opinion . My 2006 C55 AMG (+/- £52K when new) showing similar , and more, when at the same time my 2006 Toyota and her 2004 Vauxhall show zero rust.

Stick around , soon someone will pop up saying "it must have been badly repaired in the past as all MB's from year 19 whatever were galvanised. "

Whatever you choose to do I would have a VERY close look in all knooks and crannies and even behind plastic trim and any body kit before you get any work done , might save yourself multiple visits.

Which silver is it ? Notoriously difficult to match/blend . Best of luck and let us know how you get on , before and after photos etc.

 

[philnewmerc]

Thanks all. It is just the rear arch lips (and it is just surface, not worse than that fortunately), not noticed anything elsewhere apart from the usual surface rust of mechanical components. I don't have a garage so jacking up and taking off arch liners is not really feasible where I am. My plan then is a compromise: use a Dremel to remove any rust and paint that is not adhered. Paint with Hydrate 80. Paint silver. Get the whole car sprayed up and injected with something like Krown or Dinitrol e.g. this place seems to have a very good reputation Home | BUSINESS NAME (If anyone knows a waxoil type service closer to the north east that'd be great)

 

[oldguy57]

Thanks all. It is just the rear arch lips (and it is just surface, not worse than that fortunately), not noticed anything elsewhere apart from the usual surface rust of mechanical components. I don't have a garage so jacking up and taking off arch liners is not really feasible where I am. My plan then is a compromise: use a Dremel to remove any rust and paint that is not adhered. Paint with Hydrate 80. Paint silver. Get the whole car sprayed up and injected with something like Krown or Dinitrol e.g. this place seems to have a very good reputation Home | BUSINESS NAME (If anyone knows a waxoil type service closer to the north east that'd be great)

I doubt that a Dremel will be man enough to tackle that extent of rusting. I'd be using an angle grinder with a strong wire wheel, which won't remove as much sound metal, albeit rust will remain in the pits which is where your Hydrate will come in . You will find that the rust is somewhat more widespread on the arch than what is visible. I removed all the rust on the arch lips of a car with a spot blaster and 10 years later still rust free, but probably not an option for you.

 

[philnewmerc]

I doubt that a Dremel will be man enough to tackle that extent of rusting. I'd be using an angle grinder with a strong wire wheel, which won't remove as much sound metal, albeit rust will remain in the pits which is where your Hydrate will come in . You will find that the rust is somewhat more widespread on the arch than what is visible. I removed all the rust on the arch lips of a car with a spot blaster and 10 years later still rust free, but probably not an option for you.

I think I'll get a quote from a body shop first

 

[philnewmerc]

Just thought I'd giving update on two opinions from small body shops. Both said more or less the same thing: you cannot stop this and we don't really want to fix it because you'll be cross when it comes back in a year or two. Or if you want to you need to cut out this lip and then spray half the car near the repair. They were also not convinced that hydrate 80 or other rust stabilisers would help. So, I think this has to be a DIY job. I'm going to do a very small patch first and see what it looks like. Plan is to scrape off flaky paint, remove surface rust, paint with hydrate 80, paint with silver, paint with lacquer. Then lather the whole arch and seams ( and the whole car underneath) with rust stabilising wax oil type stuff. Apparently the front wings have been replaced in the past. Honestly, Mercedes and rust... Does it ever stop

 

[jdrrco]

Hi Phil. Sorry to see the hassle you're having. The Motorist at Sherburn in Elmet are very good if you intend this to be a keeper car.

 

[l5foye]

I strongly recommend that, after you remove ALL traces of rust, you cover the surface with fibreglass resin, then paint. The aim is to keep water away.

 

[philnewmerc]

I strongly recommend that, after you remove ALL traces of rust, you cover the surface with fibreglass resin, then paint. The aim is to keep water away.

Hmmm i see your thinking but if the adherence is not perfect over time it may be a gap for water to creep into and hence corrosion. I was thinking similar principle but use Bilt hamber Dynax-S50 to seal it up in waxy oily stuff

 

[alabbasi]

The body shop is correct. Like I said, if you're seeing rust through the paint, it's a lot worse than what you see. These type or repairs are almost always temporary because the metal will be pitted and in the pit there will be rust which you'll never get to unless you dip the panel.

2-3 years might be acceptable to you and if so, tell them that you understand and to go ahead.

 

[rf065]

Your pictures look very similiar to my CLK when only 4.5 years old.
Mercedes under warranty, had it repaired at the bodyworks place they used which did have a good reputation. Only for it to return 18 months later.
Again, Mercedes had it repaired at their cost (or the bodyworks place cost, who knows?), this time they claimed it would never come back, but it did, in less than 3 years.
By that time Mercedes had washed their hands of it due to age and services done outwith the main dealers.
One point to note though, the bodywork place looked just like a Mercedes forecourt with the amount of MB's parked outside waiting on work getting done and none of them very old either.

 

[philnewmerc]

OK so another place with a good reputation has suggested a 'value' repair (they were pretty honest in that it is not going to be permanent, probably 2 years): Remove rust and treat rusty lips, remove bubbling near base of wing, treat etc, respray wing up to the crease at the top of the wing, match paint as good as possible = £300 total, what do you reckon? I was then planning to soak the whole car in Bilt Hamber type wax oil including getting it into the inner sides of the wing lips.

 

[rich1068]

I've had similar work done on non-Mercedes from a body shop I've used many times and trust. Similar spec, tidy it up, make it last 2 or 3 years, not really bothered about longer because I don't keep cars. I've normally paid him about 250 cash so your 300 sounds about right.

 

[noogieman]

I thought MB cured their shi**y problems they had in the mid 90's using poor steel?
Looks like cutting corners is still one of MB's main goals?