Is it normal for the brake disc to rust?

Rust is a normal phenomenon, the brake disc has a slight rust, can be completely by the normal brake to "wear off".

To increase brake friction, most cars, with the exception of a few luxury cars that use ceramic brakes, use cast iron brakes. As soon as it rains or humidity is high, the brakes become rusty. This situation is determined by the material of the brake disc, not the quality of the brake disc. In general, this corrosion will not affect the normal braking.

The brake is mainly by the brake disc caliper, and the brake to act, which the biggest wear and tear is the brake pad. So as long as the brake xuan did not wear to the lower limit, brake oil did not deteriorate, under normal circumstances will not affect driving safety, unless the brake disc quality is not through.