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Bathroom: Replacing Toilet Ballcock/Fill Valve

Toilet fill valveBallcocks or fill valves, the culprit in many toilet problems, are much easier to replace than most seem to think. If you have determined that the ballcock needs replacement, it’s a good idea to replace the flapper cover also. (See the section: Replacing the Toilet Flapper) While some of the older ballcocks can be repaired, replacement is generally easier and more practical for the average homeowner. Many of the older ballcocks also used the float arm and ball mechanism which seemed to require regular adjustment. Newer models eliminate the float arm altogether and operate quieter and more efficiently.

First, turn off the water supply to the toilet and drain the tank. Toilet cutoff valveRemove the small plastic tube that is attached to the overflow tube near the center of the tank. Then, disconnect the supply line from the toilet. Once you have removed the supply line you will see a large nut on the bottom of the ballcock assembly; remove this nut, holding the ballcock while the nut is turned. If the nut is metal and has rusted, you may have to apply some penetrating oil to assist in removing the nut.

Remove the ballcock assembly paying attention the position of any nuts, washers, or spacers. This will ease installation of the new unit. It’s probably a good idea to take the old ballcock with you when you go to purchase a replacement. That way you can find the one that best works in your situation and you’ll be able to better describe your needs to store personnel.

The new ballcock or fill valve should be installed per manufacturer’s instructions which in most cases will involve:

  • Adjusting the height of the valve body.
  • Installing the rubber gasket or washer on the bottom of the ballcock.
  • Inserting the new ballcock through the hole in the toilet tank.
  • Applying a rubber washer, in some cases a metal washer, and tightening the retaining nut underneath the tank.
  • Insert the new plastic tube from the ballcock into the overflow tube.
  • Connect the water supply, check for leaks, and you’re ready to flush with authority.

CAUTION: When working with toilets, extreme care must be taken when tightening any of the nuts that contact the porcelain surface to avoid cracking the toilet bowl or tank.


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