If you've owned your Model S for more than a year and you live in a winter climate, chances are you're beginning to see rust on your rear brake rotor high hats. It's an unfortunate consequence of the alloy used to make the high hats. Many other brands of cars have the same issue. I've found that Audi's brake rotors are notoriously prone to rust, often requiring premature replacement. Fortunately, in Tesla's case the rotors themselves are not as susceptible to rust as the high hats are. Here is one of my rear high hats after two years of driving in Vermont... On my P85, this is unfortunate because otherwise the car is still in pristine condition. The front high hats do not seem to suffer this rust problem. A few years ago, GM developed a treatment process that makes their rotors highly rust-resistant. I believe it can also be achieved by adding zinc to the steel used to make the rotors. So what is a Model S owner to do with their otherwise pristine car? Jerry Jones, the owner of ForMyTesla.com, suggested that I try some high temperature brake caliper paint that he sells. So I took my car to a local body & paint shop, and they tried out Jerry's paint kit. The results are quite good, and the car looks like new again. Time will tell whether the paint stays intact, but based on the etching pretreatment the kit included, I'm optimistic. UPDATE The body shop tells me that there was some paint leftover, but probably not enough to do the front rotors. So, plan on purchasing two paint kits if you are doing all four rotor hats.