Recently bought a new house and the main baths toilet wobbles when you use it. Someone has told us that the flange bolts are to long and we need to replace them. How do we go about this ? the house has a concrete foundation. The caulking around the bottom of the toilet is already pulling away from the floor and I'm afraid that the wobbling will wear the wax ring out causeing the toilet to leak around the base.How do we know what size flange bolts to use.