The Toto toilet fill valve looks quite robust. It was pretty easy to take apart and clean, even though the first time I missed the final step. Here is a simple and short video of how to take it apart: How to quickly fix a hissing leaking Toto toilet with a new flush valve cap
I’ll quickly summarize:
- shut off the water through the water shutoff valve, or turn the house water off
- Remove the ceramic top cover of the tank
- Find the toilet fill valve (ling stalk looking thing)
- Remove the black rubber hose from the toilet fill valve and the water inlet pipe (should have a metal clip)
- Remove the green cover. There are two snaps on either side. It comes off pretty easily
- There is a black valve cover, or cap, which you turn counter-clockwise (to the left). Clean out any dirt. Also check a small hole in the cover that should be clear
- Pull out the black stalk in the middle. It will be long. Clean the top.
- At the very bottom of the black stalk is a white piece of plastic. This is the dirt filter. Pull this out and clean it. There may be a lot of trapped particles from the incoming water.
- Reverse everything and put it all back together.
The black fill tube can also get stiff, but if it does not leak there is no need to replace it.
All the Korky parts are pretty robust plastic and do not degrade much. Once clean the toilet should fill very well. You can also check the flapper, which does wear out after a while.