When replacing my toilet I observed that the metal flange is rusted and half of it is flush with the floor and the other half to approx 1/4 inch below floor surface. I installed a jumbo wax ring but the new toilet also leaked where the flange is below floor surface. Should I tear out the old flange and install a new flange with the pvc extender attached. Pelase any help is appreciated. The floor is wood with vinyl.