Audi TT side skirt rust... with surprises... and lots of cleaning up

In a car that is almost completely rust free, it is odd to find rust spots in the side skirts. Now with most of the body panels either well protected or made from aluminium, there is generally very little rust in the car. But the side skirts – at least the stock skirts – seem to have rust spots on both sides.

So one starts thinking, there must be something inside the skirts that holds moisture in.

Time to look inside. In this pic some of the anti-corrosion surface is already torn off. This was peeling off in places so I tore it all the way to the clean steel surface. Rust spots all right.

And inside the wheelwell, behind the plastic lining...is a huge amount of tightly packed dirt. Yes, dry mud. This rests against the surface, and the skirts being of steel (instead of plastic...for rigidity I guess?), they rust. The mud collects humidity and stays wet for a long time. There are some holes in the bottom of the skirt for water removal, but guess if they work with a 2 kilo pile of mud on top? Right.

A not-so-impressive engineering feat. The rear wheel wells (not pictured, nothing to see here) have much bigger clearances on the sides. And the rear bumper is plastic of course.

The steel seems hard enough, even though it is well rusted on both sides. The body parts are intact though.

This pic is after cleaning out the mud and brushing off the surface rust with a steel wire brush and a dish brush.

And the end product. After brushing and sanding them I painted the rusty surfaces with Hammerite Direct Rust to Metal Paint. This forms a chemical reaction that stops the rust and protects the surface. It is also really close to the Brilliant Black that the Audi has. Although I may fix some of the visible parts with body paint later on.