Brake pad vibrations that result in a high-pitched noise are the cause of brake squeal.  When pads don’t have proper insulation from the caliper, vibration occurs.  The factory will equip brake pads with insulator shims, clips, and even a silicone backing that allows the pad to stay glued to the caliper.  This helps to prevent vibrations.

Often times when brake pads become too hard brake squeal occurs.  The hard and smooth surfaces then rub together to produce a noise equivalent to nails on the blackboard.  When this occurs, it is necessary to resurface the rotors and replace brake pads.  This will eliminate the squealing.

You should also have your rotors resurfaced when you have your brakes done.  Not doing this will result in squealing.  When replacing brake pads, the rotor refinishing should be done with a non-directional finish.  This will make sure that brake pads are broken in properly.

Act immediately if brake squeal occurs.  Take your car to a highly trained technician to make sure that your brakes are treated appropriately.  And, make sure you have used car warranties to cover repairs performed.  After all, you don’t want to end up paying unnecessary costs.