There are many types of lines made from different materials, and they all break for various reasons. Rubber lines break because of natural deterioration caused by moisture and heat. They can also break. Due to the brake fluid’s constant pressure when stopping the car, they end up swelling and then breaking or leaking the brake fluid. The stainless-steel options are durable and long-lasting, but they eventually rust because of various elements and long periods of usage. Also, moisture and salt can cause corrosion of the brake. Physical damages and accidental issues that affect the brake system can also break the break line.