I rolled my car out today to finally work on it after it being in hibernation for the past 3-4 months. As I am pushing it out onto the drive, I tell SWMBO to brake. The car continues to roll. So I say louder... BRAKE!!!. She says I AM! After it rolls into the street it finally stops. After we manage to push it back into the driveway I pop open the master cylinder and it is bone dry!.. How could that be? When I parked the car months ago it stopped fine. What to do? I have no brake knowledge. I know that I should just not add fluid should I? Help, please.