What causes brake discs to rust, and is it dangerous?

ave you ever noticed? Just leaving your car parked overnight can cause rust to form on the brake discs — is it dangerous?

1. Where does the rust appear?
   Rust typically forms on the surface of the brake discs, showing as reddish stains on the metal area where the brake pads make contact.
2. Why does rust form on brake discs?
   It’s caused by moisture and water droplets, which are especially common during the rainy season. When driving on wet roads, water splashes onto the brake discs and causes red rust to develop. It can also occur if the car is left parked for a long time, or after washing the car and leaving it without driving.
3. Should you be worried about rusty brake discs?
   If the rust is minor, simply drive the car as usual — the friction from braking will naturally remove the rust. However, if the rust is heavy or deeply embedded, it’s best to have the brake discs inspected at a service center.
4. How to prevent rust on brake discs
   – Avoid parking in humid or damp areas; choose a location with good ventilation.
   – Drive regularly — normal braking helps clean the discs and remove moisture.
   – Inspect the brake discs regularly, and consider applying anti-rust coating to prevent corrosion.
   – Never spray lubricants directly onto the brake discs — it will make the brakes slippery and could cause accidents.

Source: Safe Driving by DLT
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