There are a number of ways to tell if your brake rotors are bad. If you suspect that they are bad, you should have them checked out by a mechanic. He will be able to tell you if they need replacing or not. You should always make sure your brakes are working properly. Faulty brakes can present a hazard and put people at risk for injury. If your brakes ever give out, you could cause a serious accident.
You can tell if your brakes rotors are bad if they begin to pulsate when you push the brake pedal. You get the sensation that you are pumping the brakes when you are not.
Your rotors are starting to go bad when you hear a low grinding noise when you push the brake pedal. This sound can increase to a loud grinding sound when the brake rotors get worse.
Ridges On Rotor
The noise starts when the brake pedals wear out and the metal screws rub against the rotors. Ridges similar to the grooves on the edge of a quarter, only larger, form on the rotors.
Sometimes you can hear a low grinding noise even when you are not pushing the brake pedal, and the noise escalates when you push the pedal.
Once you push the brake pedal, as it begins to grind, your car will come to an abrupt halt instead of a smooth stop. The screws from the worn out brake pedals push into the rotors and make it seem as though the emergency brake is on.
When a car is parked, you can look through the tire at the rotor and see the ridges that have formed. There is a tool called a micrometer that you can use to measure the thickness of the groove in the brake rotor. If a rotor is not completely worn out, a mechanic can machine the rotors, which remove the grooves. Some rotors cannot be machined because they will be too thin and they could pose a safety risk.