Toilet Flush Valve Replacement Parts for 1 Piece Toilet,3-Inch Flush Hole Toilet Repair Kits,Compatible with TOTO THU Series Flush Valve

Our Toto Ultramax toilet, model MS853113, ID mark CST853, was purchased in 2009 and developed a leak at the flapper in 2025, which is pretty good longevity! As described by many others online, several universal replacement flappers (blue and red varieties) both leaked and still did after using a spacer to center the flappers as recommended online. I bought this kit and noticed that bottom part (flush valve assembly) was identical to the one already installed in the toilet. So I just installed the included flapper. With the wing on the flapper set to its shortest position, the flapper fit perfectly and there was no more leak around the flapper. Great item for this toilet model. The flapper is also currently available for sale by itself on Amazon for about ten dollars less than the kit, perhaps a consideration if you have this model of Toto toilet and are having trouble finding a flapper that doesn't leak.

This worked and stooped a problem in my Toto toilet. Was fairly easy to install although it didn't seal perfectly the first time. Tip: I put a little grease on the bottom of the unit where it sits on the tank. This helps it seal and was fine after that.

It worked perfectly.

Easy to install and cured the problem of my leaking toilet. Thank you very much!!

Which is what you'd want. No leaks

Toto toilets tend to buck the prevailing trend. I’ve had poor luck with finding replacement parts at hardware stores. This one fits correctly. If the label underneath the tank cover says to replace the mechanism with THU then this will be fine. It’s a rather simple process for replacing the valve. Just undo two screws and the chain. Installation just needs the reverse.I did have to trim the sides of the sail at the end of the flapper in order for it to fit inside my tank. Instead of a rubbery seal, the flapper has a ring made of silicone. I have found that this does a better job of making a seal than the ones you normally find at hardware stores. An additional benefit is that when it does become worn, you can just replace the silicone seal without changing the flapper.One downside is that the instructions may be confusing to those who have not performed these tasks previously. It would have been better to have individual diagrams for each step of the process. However, the mechanism is relatively simple so it should not be too difficult to eventually figure it out.

I have had American Standard one piece, elongated toilets for a very long time. In my early experience with them, their flush valves were kind of finicky. As such, I actually jury rigged Kohler flush valves to fit them. I actually had one last over 10 years. It finally needed changing the other day. It seems there aren't that many options that fit one piece toilets. I didn't want to get another American Standard valve and I also didn't want to have to "custom fit" a Kohler valve.I came across this Lychee valve which looked reasonable and had pretty good reviews. It looked simple enough and the listed materials seemed like they would solve the common leaking problems.I had expected installation to be a breeze. Unfortunately, this valve is ever so slightly larger than the opening so it could not be inserted as intended. I decided that I wasn't going to give up and cut away about 1/8" from the entire bottom so that it could be flush mounted. It worked like a charm and was totally leak-free. The mechanism is simple yet makes a perfect seal.I most definitely recommend this replacement valve, but measure the opening carefully.

Recently bought a house. Toilet in the house had a problem running. Tried adjusting everything, but I could never get it to completely stopped. Finally decided to replace the guts of the tank and got this. Easy to install, works great.