The brake pads should be inspected during every oil change. Brake wear varies with vehicle use and driving habits. Constant stop and go driving is likely to wear the linings much more quickly than highway driving. Vehicles equipped with an automatic transaxle are more likely to wear the linings more quickly than those equipped with a manual transmission.
Driving habits also affect brake wear. Aggressive braking from high speeds is likely to wear the linings more quickly than slow gradual stops. Aggressive braking also generates much more heat which could result in premature brake rotor wear, potential rotor warpage and wheel bearing damage, as the heat generated can decrease the ability of the grease to adequately lubricate the sealed wheel bearing.
Some brake pads are equipped with audible wear sensors. When the brake linings reach their wear limit, a small metal tab begins to contact the brake rotor, making an audible, but light scraping noise which initially occurs when the brakes are used. Eventually it will make a high pitched scraping noise any time the vehicle is moving, being most noticeable at slow speeds.
Sometimes brakes do squeal even though the brake linings are not worn. In this instance, the brake squeal usually diminishes when the brakes are used hard.
Causes of brake squeal include the following: