Hiring a repair person is likely the best course of action ... Next, there are two large screws on each side of the toilet keeping the tank attached to the lower half, which need to be removed.

For this reason, flapper valves generally need replacement more frequently than other toilet parts. The Overflow Tube ...

UNIVERSAL DESIGN - The toilet replacement parts inside tank fits 3-inch plastic flush valves, compatible with American Standard and most toilet brands with 3-inch toilet tank valve opening.