If your brakes fail,

Try not to panic, and think quickly. Engage the emergency brakes. Although total brake failure is very rare on modern vehicles, it is still crucial to know what to do should brake failure occur. Try pumping the brake pedal to temporarily restore hydraulic brake pressure. If this does not work, apply the parking brake gently but firmly while holding the release button. It is a good idea for new drivers to practice a parking-brake emergency stop under controlled conditions with a qualified driving instructor.