How to Change the Tank Gasket on a One Piece Kohler Toilet

Shut off the toilet's water supply. The hose running out of the wall below the toilet tank is the water supply line. Turn the valve on this line to the off position.

Empty the tank of water by flushing the toilet. Wipe away any additional water with towels or rags. Detach the water supply hose using a wrench.

Place old towels or rags on the floor around the toilet in case some water leaks onto the floor.

Take the top lid of the tank off. It should lift off the tank easily.

Locate the tank gasket. The gasket is a round, black, rubber piece that is stuck onto the bottom of the tank. Pull up the gasket so that it is no longer attached to the tank.

Put a new gasket in place of the old one. Apply a thin layer of sealant onto the new gasket to keep it in place. Allow it to dry for two hours.

Place the lid back on the tank. Make sure it lays evenly so it doesn't slide off.

Attach the water supply to the tank. Secure the water hose with a small amount of sealant. Turn the water supply back on. Once the tank fills with water, flush the toilet. Make sure there are no leaks anywhere.