The Brake Line is an integral part of your car’s braking system. Today, most brake lines are hydraulic, which means that fluid is used to transfer power from your foot to the brakes. When the brake pedal is applied, fluid from the master cylinder is transferred to the brake calipers, forcing them to clamp down on the rotors. Although brake lines will typically last the life of your car, hydraulic fluid leaks can damage the hose and connections.