SLK R170 rear wheel arch rust tell tale

[DickyC]

Although I'd seen them before I'd never investigated the bulging ends of the rear wheel arch rubber trims. Just part of it, I thought.



The grip part should be nice and parallel like the section higher up. The bulge means the seam beneath is rusty.



The paint shop, doing the wheel arches, bless 'em, just painted over it. So I dug out the rust and did the Kurust and Hammerite Underseal routine and will investigate further next Spring. The car has a had a lot of work done and I was disappointed I missed this area of rust. Even more disappointed with the paint shop who knew I was trying to beat the rust. They did do a nice job on the bodywork though.




These are the rubbers.



They are unobtainable now and I'm going to have a go at making some by modifying standard boor or bonnet strip available by the metre. Even though they couldn't help with these, the Parts Department at MB Newbury have been very helpful during the car's refurbishment.

[Ian-27xza]

Thanks for posting your pictures.

My 2003 320 SLK will be going through a thorough restoration over winter (new wings, all rust spots sorted, screens-out respray).

[DickyC]

Ian-27xza said:

Thanks for posting your pictures.

My 2003 320 SLK will be going through a thorough restoration over winter (new wings, all rust spots sorted, screens-out respray).

Nice. I only did the bits that needed doing so other than the rear screen it wasn't a glass-out respray. The rear screen came out to sort a patch of rust on the driver's side C pillar. Finding someone to do the underside was tough. Silchester Garage did it: cleaned, repaired and painted for £250 which was good.

[trevalvole]

DickyC said:

Finding someone to do the underside was tough. Silchester Garage did it: cleaned, repaired and painted for £250 which was good.

That's interesting. I'm wondering about getting someone to protect the underside of my slightly newer C320 sports coupe. Did they do the whole underside including the wheel arches for £250? What did they paint it with?

[DickyC]

trevalvole said:

DickyC said:

Finding someone to do the underside was tough. Silchester Garage did it: cleaned, repaired and painted for £250 which was good.

That's interesting. I'm wondering about getting someone to protect the underside of my slightly newer C320 sports coupe. Did they do the whole underside including the wheel arches for £250? What did they paint it with?

More complicated than that. When I was discussing with the paintshop what they would do they refused to do any work on the underside. Body and wheel arches yes, undersides no. Silchester Garage, classic Mercedes specialists, agreed to do it and it worked out fairly cheap because they could only find surface rust. The problem for me was finding rust in the wheel arches the day before it went into the paintshop. The paintshop did the body and the welding had to wait until I got the car back. I was with the welder when he did the rusty grommet holes. It was not all of them and the ones that were had the problem disguised beneath paint and underseal. The seals stayed in place and continued to conceal the rusty seams. Back to the paintshop for the wheelarches and when it came back the seals had gone and the rust painted over. I didn't notice the seals had gone until after the car was back. And I didn't notice the rust - or recognise the significance of the swollen seals - until I had sourced replacements.

I haven't been back to the paintshop about the missing seals and painted over rust but I've emailed twice. No response.

Not sure what paint Silchester Garage used but it wasn't black which interested me. I'm sure they'd tell you if you rang.

The wheel arch responsibility grey area caught me out. How people with little mechanical knowledge would have a car refurbished I don't know. Thinking about it, they probably wouldn't start.

[trevalvole]

DickyC said:

Not sure what paint Silchester Garage used but it wasn't black which interested me.

May be it was something like this, which is brown?

https://bilthamber.com/product/dynax-ub/

[DickyC]

Spot on. It is brown.

[DickyC]

Maybe I should put this in Reader's Cars. While it was enduring the World's Most Lethargic Refurbishment, I bought an SLK32. The blue car is my wife's beloved SLK230. She's had it for twenty years and doesn't want anything else. But she's had it so long she's a bit windy about driving anything other than an R170 so the SLK32 ticked several boxes.

If you know what I mean.

[Dewi 2]

Just in case this might be relevant.

I am dealing with (the usual) wheel arch rust, on my 23 year old W208 320 (owned 20 years).
Just surface rust with only two perforations, both in the exact corresponding positions - front wings, lowest point, just forward of the wheelarch.
Very small, so fixable.

After a quick investigation, the reason for those holes immediately becomes glaringly obvious.
The front wheel arch liners have small gaps, front lower outer corners.
Dirt/mud goes through those gaps, sticks to the inside of the wings, retains dampness and corrodes.

All that it needed were patches to cover those gaps, then no trouble, but not many owners would go looking around prior to corrosion occuring.
It did take 21 years to corrode, but still not up to image that Mercedes consider they have, particularly when comparing to my garden rubbish car, a 1995 Vauxhall Cavalier which still has wheel arches looking like new.

Perhaps this might also apply to other models. Take a look at your wheel arch liners (if you intend to keep your car for some time).
Probably something as simple as gaffer tape, would solve such design flaws.

[DickyC]

Thanks for that Dewi. Yes, in a word. Every couple of years I remove the front wheel arch liners, remove the bolts at the bottom of the front wings, slacken the ones in the door shuts pull the bottom of the wings out a bit and hose them out. It's leaf mold in my case but it still blocks the drain holes. The car will be 24 years old next month. We've had it for 20 years and have just had the front wings replaced. So it was worth doing. In the case of the R170 it's the bracket that joins the front wing, bumper and inner wing that suffers most. It's an uncharacteristically poor piece of design. Fixed now.