When Should I Change My Brake Discs?, When you press the brake pedal, the Brake disc, caliper, and brake pads all work together to bring your car to a halt. To stop, the brake pads are pressed against the brake disc by the calipers. This creates friction with the brake disc, slowing the vehicle to a stop at high speeds. Given the foregoing, why do so many drivers not know when they should change their brake discs, given how crucial they are to the vehicle’s performance, operation, and safety?