Grinding to a Halt
Hearing a grinding noise when you break?
Q: From time to time, I hear an awful grinding noise when I apply my vehicle’s brakes. It does not happen every time I brake, but when it does, the grinding can be heard and felt in the car. So far, the service center I use has been unable to find a solution to the problem.
A: Brake noises should be checked immediately by a competent auto technician, since they are often a warning of a serious problem. Some noises, however, may be normal.
Since you have had the brakes checked at your service center and no problem was found, that grinding noise you hear from time to time could be caused by a light coating of rust on the brake rotors. This can happen if the car has been parked for several hours with wet brake rotors.
If the grinding noise is caused by this light coating of rust, it should only be heard—and perhaps felt—during the first few stops. After these brake applications, the brake pads should have removed the rust from the rotors and restored normal braking performance. If your car has alloy wheels with large openings, you should be able to see a light coating of rust on the brake rotors before you start driving.
Some drivers describe the sounds made by the antilock braking system (ABS) as a grinding noise with vibrations that will definitely be felt in the vehicle. If the noise occurs only during panic braking or when braking on a slippery surface, it could be the ABS doing what it was designed to do.
If, however, the grinding occurs when neither of these situations is present, you need to have the car checked again immediately.
This article originally appeared in the May/June 2019 edition of AAA World.