Automotive Q&A.

Byline: Brad Bergholdt

Q. Can you shine a little light on brake squeaking? I've been told it's somewhat normal, shouldn't happen, the brakes are self-destructing, and recently you wrote that it's a sign the brakes are OK but might soon need to be replaced. How can I be sure of which situation I might encounter?

_Pam Lorens, Augusta, S.C.

A. Great question, Pam. Brake squeal has several facets, from harmless but annoying noise, to rotor-grinding trouble.

Let's start with the usual cause, which is brake-pad vibration. Your car's disc brake pads resemble large Oreo cookies, with an outer layer removed. The filling, or friction material, is …