Rust on new sitting rotor normal?

Maintenance/Repairs
1

Why would this rust be on a new rotor? It has been sitting in a nonhumid climate controlled storage for a year. I opened the box and it looks like this. It was not like that when first purchased.

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2

It’s steel.

Steel rusts when not used

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3

You might very well think that the storage area was controlled and non-humid, but it was not, the photo shows condensation build up and even drip lines. The Discs “8 o’clock’s” position was probably low point and assuming it was standing on edge, you can see the rust build up as the condensation dripped down the rotor. It if really was bone-dry there, the rust coating would not be so heavy and it would be just a “light dusting” like layer
 Some “elbow grease” and sand paper with take care of it, or an orbital sander will make short work of it. Have you ever looked at your disc rotors after a couple of day’s rain when the car was not driven?

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4

That little clean spot was when I hit it with a little brake clean. I’m going to try and clean it all off with some more brake clean.

It was laying flat in a closet in the house. House rarely, if ever, gets above 50% humidity.

The same brand ones that have been on the car do not even have that much😆

5

It is iron.

But iron still rusts just like steel.

Hit is with a little sand paper or just install it and the brake pad will clean it right off.

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6

This looks fine. Rotors will get this way if they sit, including on the car. It doesn’t look pitted or like it is flaking apart or anything. Just install and drive. There is no need to clean this up.

For long-term storage, some folks like to wipe with oil or for even longer term, cosmoline. This stuff is NASTY and can take a lot of work to remove though.

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7

Normal. I bet a Scoth-Brite would clean that right up. I’d just spray them down with brake cleaner, put them on the car, and let the pads do the work.

8

Before installing, wash rotor’s surface thoroughly with warm water and soap to remove any protective coating. Otherwise it may rub off and clog the brake pads. Otherwise, just minor surface rust, not a worry. when doing brake work on my own cars, I usually rub the brake drum or rotor surfaces lightly with 160 grit AlO2 sandpaper, oriented roughly at 90 degrees to the direction of rotation, radially, inside to outside on rotors. Helps prevent squeaks.

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