The ability of the Pontiac disc brake pads to be converted to dust is why no damage occurs when friction is being created to stop your vehicle's motion. In each of the brake calipers on your Pontiac is a pair of disc brake pads. These pads are forced against the smooth disc-like surfaces of the rotors by the piston in the brake caliper. If for any reason this force is compromised by a leak in the system, the friction being created will be at a reduced level. The owner of a Pontiac will know when it is getting close to the time to replace their disc brake pads when the reservoir of the brake master cylinder is getting low. The brake fluid that was in this reservoir has moved to the brake caliper as the piston is moved out to compensate for the loss of material on the disc brake pads. If brake fluid is added to the master cylinder when a brake job is completed replacing the front disc brake pads, the piston in the caliper will be moved back into it forcing the level in the reservoir to increase. If too much was added, it will overflow and be needed to be cleaned up on your Pontiac before it makes contact with the paint. If the Pontiac disc brake pads are not replaced before the padding material is completely gone, then the metal backing plate this padding material is attached to will come in direct contact with the metal rotors. This is when the driver will hear a grinding noise from the front wheels when the brakes are applied. This is the rotors being damaged because of the lack of pads that should be there.