fiat Available Here. Since it is just as important to be able to stop while driving as it is to be able to go, cars have a brake system. Brake lines are part of that crucial brake system. Many vehicles have hydraulic braking systems that use fluid to transfer braking power from the foot to the pedal to the brake. That fluid is carried through tubes called brake lines. If a brake line malfunctions, the brakes will not work. Inspect your brake lines to make sure that they are not showing signs of wear like frays, cracks, and corrosion. Replace your lines if they begin to break down.