salis

Hi guys,

I just noticed a scratch on the rear wheel arch and it seems like there is a small dot of rust. Is this possible? The car is a 2008 S500. I am attaching a photo below.
Also, I noticed a bump on my front tyre - do you guys think this is dangerous? Should I replace the tyre? Also attaching a photo.

thanks in advance!

1bad540

yes to both.

salis

thanks, I will change the tyre.
But how is it possible for a 2008 Mercedes to rust? I thought the rust issue was sorted by then?

DaveW68

Because there is a chip or scratch then went all the way through the paint & primer, that's how.


To repair, just clay bar the area, or use a good polish to rub the rust off. Then dab some touch-up paint into that spot and you'll be good to go. It shouldn't come back.

salis

thanks!
I thought that a Mercedes from 2008 should not rust.. not very impressed..

steveb9771

All steel with the exception of stainless will rust if the integrity of the protective coating is compromised. Even galvanized iron will rust if the coating is scratched down to the bare metal.

mrbobby

Stainless steel doesn't mean that it won't rust , it means that it will rust "less". We see very expensive German stainless steel (medical instruments) rusting sooner or later.

steponthegas

The tire looks bad.

pleeson

Look at any car's brake rotor after a wash, exposed steel oxidizes in minutes.

Unfortunately, when it has been left for a while, the rust often extends farther under the paint than you think. You need to scrape the paint back with a sharp edge to expose clean metal, prime and paint the area.
Just dabbing touchup paint won't work -- you'll get a big bubble later on.
Many YouTube videos will show how it's done.

And also agree that that tire is shot -- looks like pothole damage.
Be sure the wheel is round before you put a new tire on it.

Good Luck!

salis

ok, thanks!

salis

Might be a stupid question but how do I know what tyres I need to fit? Obviously I can check the current tyres, but I can't be sure that the previous owner got the right size. I have already checked my manual and official car specs, but I can only see the rim size.

thanks a lot!

steveb9771

The original tire size should be on a data label inside the driver side door jamb.

salis

thanks!

salis

btw, does it make sense to fit run-flats? These should be safer than the standard ones, right?

DaveW68

They are definitely safer if you're fleeing the scene of a crime and the police set up road spikes to try and stop you. Otherwise, go with regular rubber as the run flats will ride harsh and will eventually wreak havoc on your air suspension.

salis

thank you!

pleeson

I had run flats on a BMW 3 series -- terrible.
The first time I hit a little pavement crack I thought something broke in the front end.
A switch to normal tires made the ride and handling much better.
Avoid them at all costs!

shawnepps1

;l

KNBS550

Not unless he is in the UK or any other part of the current or former English Empire.

alx

Lol. They do rust. Even if there is no compromise of the coating- rust will just bubble up. It used to take 5 years now it takes 7-10- especially in the regions where salt use is excessive in the winter (like north east).

Quadcammer

this thread is painful.

xpl0sive

I thought most body panels on w221 were aluminum?

akssdd

^^