I had the same issue with the same flush valve on a 2013 or 2014 version of the same toilet. Problem began with water always running. Plumber came and said the flush valve wasn’t repairable so I should buy a whole new toilet. Grrr!
I called Toto directly and they matched up the current replacement flush tower part and then I ordered it online from a seller. About $75 with shipping. Took a month to arrive. Super hard to remove the faulty flush valve! But because I read on this blog here about how to do it (thank you!) I kept trying. The piece is a little different than in Terry Love’s photos so see my images attached (2 brass metal blocks at screwed on gasket base). Eventually it did finally twist off after lots of effort …maybe because I had retrieved a hammer to smash it off as the next solution?? No hammer required.
With the faulty flush valve tower off, my replacement THU469R-A with the green top (no instructions were in the replacement part bag, grrr) now had to be separated into 2 pieces to be able to access the screw heads on the bottom part with the base gasket that fits to the porcelain hole opening. It was a little tricky to separate those two pieces as well. Tip: line up the tiny nubs on the bottom piece with the small vertices of the top piece and pull up. To install the bottom piece with 2 brass blocks, you’ll need to rotate those block pieces inward so the piece can fit into the opening, then use you finger to rotate each block into final outward position and screw ithem tightly to secure the bottom piece to the tank. Then add the top piece of the tower. Connect clear filler hose.
Next step is the little black and white colored cassette piece attached to end of red plastic covered wire. As was mentioned by the previous poster, this replacement is double the size of the original one and the tank interior isn’t quite large enough to fit it!! Maybe 1/8” to 1/4” too shallow to the back of the tank to fit it while aligning with the trip lever. So frustrating. After all this. I ended up hammering the plastic cassette (!) slightly flatter at that back edge…because I didn’t have anything to lose at this point. Otherwise I’d need a whole new toilet. So I used that hammer after all and it did just barely fit in after the edge smashing but it doesn’t connect 100% onto the trip lever’s connection (not related to my edge smashing) so it’s not on there quite straight. It’s been 3 days now and twice it’s become too loose or fallen off. It’s an easy but irritating fix to open tank lid and secure it back on there with the little Y-shaped locking pin, but yes I may have to go to Toto directly like the original poster here to request a free new toilet if it keeps falling off. Or hammer it more?!
This whole issue needs a real solution because we have a second of this exact same toilet model upstairs. Its flush valve tower will fail at some point too since they’re 9 yrs old now. On a positive note, our third bathroom has a 2006 Toto Ultramax (purchased thru Terry Love if I recall correctly) with the normal chain-activated flush and flapper and we’ve had no problems with that one. We have Toto washlets on all 3.
Or whoever is reading this in the future, I hope the photos with notes I have included here will help you through this process more easily! Or you’ll just get a pricey new toilet from the start
