Water should not come out of the vacuum breaker when the Bathroom Faucets is turned on, it is a one way valve that should only let air in. If water comes out of the vacuum breaker then the internal parts are most likely not working properly.Repair The Vacuum Breaker: Remove the cap covering the vacuum breaker by applying even and upward pressure on both sides of the cap. Under the cap you will see the vacuum breaker parts. Try to clean them. If cleaning the vacuum breaker parts does not stop the leak then you will need to buy Antique Faucets replacement parts at a local plumbing store.