There are Chevrolet brake drums on all cars of this make that are built without disc brakes. If they are used at all today on modern cars, the brake drums will be found on the rear wheels. This is the actual surface of the braking system that the pressure of the brake shoes is applied too in order to stop you car. The brake drums on your Chevrolet can be damaged if the padding on the brake shoes has worn down and the rivets that hold the friction material to the backing plate come in contact with the inner surface of the drums. A driver can suspect this when they hear a grinding sound of metal to metal contact coming from the rear of the vehicle when the brakes are being applied. When this sound is heard, a brake job should be conducted immediately and the owner of the Chevrolet should be prepared to have the brake drums turned or replaced. The turning of the Chevrolet brake drums is accomplished on a lathe where the surface in the drum is removed until it is smooth again. This process removes the damage that the rivets did when they made contact with the surface. Before this is done and once completed, the thickness of the brake drums interior surface area should be measured. There is a minimum specification for this thickness which is permitted so the appropriate amount of heat can be dissipated from the drum and the brakes do not overheat. If not within the set specifications, the drums will have to be replaced. If overheating of the brake system on your Chevrolet does occur, the brake surface will become glazed and friction from the shoes will not be sufficient to stop your car. This could lead to an accident and the reason when a technician informs you to replace this brake part, it should be done.