How do I install a new toilet flush valve?

Flush valves are held to the tank by one large jam nut on the bottom of the tank. Installing a new flush valve usually requires removing the toilet tank from the bowl, which can be rather complicated. However, wall-mounted tanks may not need to be removed.

  • If the toilet tank must be removed, turn the water off completely, flush the toilet and hold the trip lever down to evacuate most of the tank water. Use a sponge to remove the remaining water. Disconnect the tank's inlet fitting from the water supply. If the flexible riser tube is damaged, replace it.
  • Then, unscrew the two rubber-gasketed bolts flanking the flush valve. These bolts go through the tank and bowl flange, with nuts beneath. Use caution-forcing the bolts may cause you to break the tank, bowl or both. Use plenty of penetrating oil on the threads. If they still won't budge without force, try wrapping masking tape around a hacksaw blade and sawing with the teeth facing you, so the blade cuts on the 'pull' stroke. The layer of masking tape will protect the bowl's glazed surface from saw scratches.
  • The tank should now lift away from the bowl. Lay it upside-down on a throw rug or newspaper padding to protect it, and unscrew the large nut holding the flush valve to the tank. Use locking pliers plus penetrating oil and extreme care to avoid breakage. Clamp a well-padded locking plier/wrench around the flush valve to keep it from rotating inside the tank.
  • Install the new flush valve (see image) according to the directions. The rubber gasket goes on the inside of the tank to prevent leakage. The flat washer fits on the outside to prevent tank damage.
  • Use new brass tank hold-down bolts, which will remain workable. Tighten the bolts just enough to compress the tank's soft rubber gasket and keep it from leaking.

Check your state and local codes before starting any project. Follow all safety precautions. Every effort has been made to ensure the accuracy and safety of this information. Neither Westlake nor any contributor can be held responsible for damages or injuries resulting from the use of the information in this document.

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