Ideal Standard valve assembly replacement?

If it's the float ball and arm type you don't have to replace. Turn off the water to the cistern Remove the float arm, Usually held by a pin, remove the large knurled nut and plunger on the valve assembly the large washer is what that plunger pushes against to shut water off and its likely the washer has 'holed' replace this washer re-assemble the arm turn on water job done. If it over fills re-adjust the rod that pushes against the plunger.

Bob
June 2009