View Full Version : Toto fill valve gasket leaking

Andy Griffith
08-30-2012, 03:50 PM

I have a Toto MS854114S that is leaking where the nut holds the bottom of the fill valve to the tank. At first I thought it was the supply line and replaced that, but then noticed it was coming out between the white nut and the tank. I tried tightening that nut a bit but it just made it worse if anything.

Looking around the net it looks like the original part number for the valve is TSU07A.5? Also, it appears that I can't just replace that gasket, and I have to replace the whole valve?

Is this something that lowes or HD would carry or do I have to order it over the net?





08-30-2012, 04:31 PM
If your local hardware store has the korky 528T fill valve, it is the same as the original valve. If not, get the Korky 528mpk at Lowe's; it is identical to the new Toto universal replacement fill valve. You might try draining the water and removing and reinstalling the old valve. Check the gasket on the inside of the toilet, rinse off, etc. Maybe lightly sand the inside of the tank around the hole to make sure it is smooth for a good seal. But the gasket may just be done, partiucularly if exposed to chlorine or bleach on the tank water. Hope this helps.

PS you need the 528T or 528 mp. The regular 528 white cap one will not work. You need the blue or silver cap one.

08-30-2012, 04:53 PM
You can also pick up a new Red Flapper for it if that is needed. The replacement will fit over the existing pins on the tilt valve you have.
www.terrylove.com/korky (http://www.terrylove.com/korky)

Lowes carries the Korky products.


08-30-2012, 06:44 PM
To put an even finer point on it, Home Depot does not carry the proper 528 fill valve (the 528T or 528MP a/k/a 528MPK at Lowe's). Only Lowe's (and a zillion local stores) do.

Andy Griffith
08-31-2012, 12:45 PM
Ok thanks very much for the information. Managed to get a 528T from the local hardware store. Just installed it and no more leaks. The gasket on the old valve was completely compressed.

However, I'm wondering if I'm ok on this fill level. When setting the height I used a small straight edge to come across from the top of the overflow tube to the corner of the flush valve as specified in the instructions. I then carefully removed the fill valve, locked it in place and reinstalled it.

Finished the installation and turned on the water. The water stops filling the tank right at the top of the over flow tube. No water flows into the over flow tube but the water level is right at the top of the over flow tube. So I rechecked with my straightedge and the valve corner was now a bit higher than the top of the over flow tube by about 1/8-1/4". I don't understand why that changed unless it changes a bit during the twist/lock process?

Anyway the water level is about 1 - 1/4 to 1 - 1/2" below the bottom of the flush handle opening so I think fulfills the code. Is this water level ok?



08-31-2012, 01:57 PM
Looks like you have done a nice installation. Looks like you have an eighth of an inch or so there. One of our toilets came from the factory like that. If I wanted to tinker, I might lower it a notch, but unless you start getting running or overflow, which you won't, most likely, I would leave it alone. If you do see some overflow or running, you know how to fix it. Just turn off the water at the wall, flush, rotate the valve (the head will move ever so slightly down when you do), then when unlocked just nudge it down one peg (because it seems a smidge lower when unlocked, make sure you actually go down a peg) and then lock back in position, turn on water, and voila. (My little trick is to unscrew the nut underneath, hold the head in position, and rotate the stem, rather than the head, to lock and unlock. That way you don't have to disconnect anything or take anything out of the tank.)

The code issue is the critical level being an inch above the top of the overflow tube, which it is, so you're fine. When you turn the thing to lock, it rises just a bit, explaining the rise in water level. However, by rising, it's putting the critical level even higher from the top of the overflow tube, so there's no code issue. You also want the flush lever to be more than an inch above the top of the overflow tube, which it is (as you haven't touched it). So it's technically fine, as well as practically fine.

(The "critical level" relates to the backflow prevention ("anti-siphon") feature of this and other code-compliant fill valves. An anti-siphon valve will not allow water from the tank to be sucked back into your plumbing (i.e. drinking water supply) if, for example, you drain your house water system to do repairs. The critical level is marked on every compliant valve, and it is the level above which the anti-siphon feature will no longer work. So, by putting the critical level on the valve at least an inch above the top of the overflow tube, you minimize the possibility that water would ever be higher in the tank than the critical level.)

08-31-2012, 02:16 PM
OFten, there's a fill line printed on or scribed into the tank. If the water level is higher than that, you'll be using more water in the flush than by design (the flapper valve is designed to close when it drains to a certain level and if the level starts out high, more water is used). Normally, that fill line is around 1" or so below the top of the overflow tube (varies by model and brand). I'd lower the tower a bit.

08-31-2012, 02:28 PM
The water should be below the top of the overflow tube by about 1/2" inch. You can also get by with 1/4"


08-31-2012, 03:16 PM
The guys are correct, of course, as to how it is supposed to be, and I hadn't really thought about Jim's concern about wasted water. (Bad me. Bad!) Code doesn't enter into it here, but perhaps other concerns do.

If you perfectly-align the bottom of the blue cap with the top of the overflow riser, you get a built-in 1/2". That's because the water cutoff line on the 528T (and the other 528s) is 1/2" below the bottom of the colored cap. And all of my Totos have a stamp in the tank saying that the right water level (to get a legitimate 1.6 gallons used per flush) is 1/2" below the top of the riser.

I was just taking an "it aint broke, don't fix it unless you want to" approach. And in many months, I haven't bothered to lower the water level in the Toto that came from the factory set at about 1/8" from the top of the overflow riser, and it hasn't been any kind of practical problem. But they're right.

If you decide to adjust it, try my "spin the shank" from underneath the toilet method described above; I think you'll find it easiest. If you do it, of course, recognize that you are unsealing the gasket between tank and valve [duh] so any water in the bottom of the tank will dribble out. I'm sure you know that, but I didn't want to not say that in case you didn't.