How to Replace a Kohler Flush Valve Seat

Shut off the toilet's water supply and unscrew the supply line from the fill valve. Flush the toilet and continue holding the handle down to remove as much water as possible from the tank. Soak up the remaining water with a sponge or towel.

Disconnect the tank from the bowl by unscrewing the tank-to-bowl bolt nuts underneath the bowl's rim with an adjustable wrench. Lift the tank off the bowl and set it on a bath towel. Peel off the old black foam tank-to-bowl gasket from the lock nut on the bottom of the tank.

Unscrew the flush valve's lock nut with a large pair of slip joint pliers. Separate the small black rubber fill tube from the top of the flush valve and disconnect the lift chain by hand. Pull the entire flush valve assembly out of the tank. The tank's attachment plate will separate when the valve is removed.

Unscrew the fill tube, the thin plastic tube in the center of the flush valve, from the flush valve's seat. The flush valve canister and seal will separate with the fill tube.

Install the new flush valve seat using a new shank washer and tank-to-bowl gasket. Reassemble the parts in reverse order. Reconnect the water supply and turn the water on. Flush the toilet several times to assure proper operation.