Mansfield Tank To Bowl Seal with Mansfield's new style bolts with a rubber head. This innovation makes it easier to install and remove the tank from the bowl. 630-0004, 630-0204. Mansfield's tank to bowl seal is made of a harder rubber than other seal and is specially designed to work with Mansfield toilets. First you place the tank to bowl seal over the nut on the bottom of the flush valve then place the 3 rubber top bolts through the tank. Then carefully place the tank on the bowl lining up the 3 bolts with the 3 holes in the bowl. Finger tighten the 3 nuts on the bottom of the bowl. Use a level to make sure the tank is level. Once the tank is level and all 3 bolts are hand tight use a wrench to tighten them one turn at a time on each bolt so the tank stays level. be careful to not over tighten the bolts because you could break the tank.