Toilets are not difficult to fix, because there aren’t many parts that can go bad. Inside the tank is a float mechanism attached to a water intake valve for filling the tank with water. A flapper allows the water to flow into the toilet bowl when you flush the toilet handle. There’s also an overflow tube that allows water to flow into the bowl even when the flapper is closed, so water won’t overflow onto the floor if it rises too high. If all of these parts are old and starting to fail, you might want to replace them all at once.
5 Do not overtighten the toilet mounting bolts or you could crack the porcelain tank. Universal toilet repair kits include the water valve, overflow tube, flapper, and mounting bolts.
Remove the Flush Handle, Mounting Screws, Overflow Tube, and Flapper - Unscrew the plastic nut on the inside of the flush handle, using pliers. Unhook the chain that connects the flush handle to the flapper. Slide the flush handle forward, out of the hole in the tank. Remove the two nuts beneath the toilet tank, located to the left and right of the tank center, using an adjustable wrench. Lift the tank off the base and set it on the floor. Remove the two mounting screws at the base of the tank, and their accompanying washers.
Insert new toilet mounting bolts into the two holes in the bottom of the tank, with rubber washers as explained in the accompanying instructions. Place the toilet tank on the base with the screws going down through the holes in the toilet base. Tighten two nuts with washers onto the bottom of the mounting screws with pliers.
Place the small rubber tube attached near the top of the water intake valve inside the overflow tube.