Rusting brake rotors



I brought my vehicle to an independent repair garage & the mechanic told me I needed new brake rotors & pads for all 4 wheels, despite having only 6,000 miles on the front brakes and 12,000 miles on the rear brakes. He said the rotors rusted since I didn’t drive the car enough (I leave the car at my beach house on Nantucket island all Summer and I only drive it on weekends for a few miles). He said the new rotors are made in China and can’t be “turned down” because they are too thin even when new. Do you know of any spray (silicone or oil?) I might use to protect the rotors from rust without affecting the braking power?


No spray, but no new rotors, either, unless you’re having braking problems. Rotors rust, braking rubs off the rust.


Did you bring it in for service on the brakes or for some other reason?

Brake rotors are typically cast iron and they rust. This is normal. Cars that sit for extended periods, especially with salt spray nearby, can rust more than those driven more often. Unless there is severe pitting or some vibration upon braking, I wouldn’t do anything. It should be scrubbed clean within a short time by normal braking action.

It’s true that the budget rotors are often thinner to begin with and can be made from inferior materials. However, unless you are having to replace them due to some performance issue, the rust is only cosmetic.

You cannot coat the braking surface with anything that will stop rust and not affect braking performance, especially oil!!

If you are plagued by rusting rotors, you can spring for more expensive rotors with a plating or anodizing finish that will significantly slow down the inevitable oxidation process. They are likely to be 3x the cost of standard rotors assuming they are even available for your year/make/model. Even then, the actual swept area of the rotor is still bare metal…


Need a little clarification here. Does it sit all summer unused or is it driven a few miles every weekend during the summer? Is it driven regularly during the winter?

If it sits all summer without any driving, you could jack it up, remove the wheels, spray coca cola or phosphoric acid on the rotors, let it sit for a couple of minutes, then wash off and replace the wheels. This puts a coating of iron phosphide coating, that looks like corroded aluminum, on the steel, but it will keep it from rusting and its very thin so it will rub off quickly when the brakes are used.

Otherwise, don’t worry about it.