On Dec 6, 11:58*am, "Larry B" wrote:
I have 2 old Case toilets in my home. I have plenty of parts and just
changed the seat and plunger seat on one of them. The fill does shut off but
now. But, after the tank has filled 99% , there is now a prolonged period of
hiss-filled "topping off". *Any suggestions on how to correct this
phenomenon? Thanks.

If there is a screw on the top center it needs to be slightly
tightened down .