View Full Version : Toto bowl doesn't fill high enough.

08-28-2007, 11:30 PM
I have a Toto toilet with (Model #??) "C854" stamped on the inside of the tank). It doesn't fill the bowl after a flush unless I hold the lever down until the waste is discharged. It only fills to half (or less) the proper height if I release the lever immediately. How do I fix this problem? There doesn't seem to be any adjusting mechanism on the either the flush or fill valve that have any affect on it.

08-29-2007, 05:02 AM

What you have is the MS854114 Ultimate toilet.
If the water is not filling the bowl but the tank is being filled, check the fill tube (small rubber tube) coming from the fill valve (blue valve) to the overflow tube (white tube where the blue flapper is connected to) and make sure water is going down the tube.

08-29-2007, 10:16 AM
Thanks for your responsee. The fill tube is connected to the overflow tube so that it discharges into it the way you describe.
It seems to me that the flapper valve is closing too quickly, and that less of the residual water at the bottom of the tank (after the waste is discharged but before the flapper valve closes), doesn't flow into the bowl. The water level in the bowl is about 1 to 2 inches below where it should be when that happens.
The chain on the flapper valve has very little slack. to tighten it up more would prevent it from completely closing.

08-29-2007, 11:09 AM
If you have residual water in the bowl immediately after the flush, it isn't working right...basically nearly all the water gets sucked down, then water from the overflow tube during refill of the tank fills the bowl up as far as it can go.

Now, if the water level in the tank is not set right, it may not run long enough to fill to the max. Once finished, the tank level should be in the order of 1/2" below the top of the overflow. If it isn't, raise the level and see what happens.

I think it was already suggested, but if not, slowly pour water into the bowl - a gallon should be more than enough. Then let it sit to equalize. that is the max the bowl can hold. Compare that with the level it fills to on a normal flush and let us know.

08-29-2007, 01:17 PM
That's how I thought it should work, too. The water level in the tank is about 1/8" inch below the top of the overflow tube -- no matter whether I hold the lever until the waste discharges from the bowl, or release it immediately. However, when I release it immediately, there's about 1.5-2" of water in the tank (above the lip of the flapper valve where it closes) that doesn't run into the bowl because the flapper closes so quickly (in my opinion).

08-29-2007, 03:51 PM
The low-flow toilets almost universally do NOT empty the tank...this is done on purpose. Just like a water tower provides pressure for all of the houses downhill from it, that height in the tank provides a better flush. The bowl is NOT typically filled by water at the end of the flush, it is filled by the water dumping down the overflow tube during refill of the tank. The stream from that hose should be strong while the tank is refilling, if it isn't there could be a kink or blockage. But, once the bowl is filled, any extra goes down the drain. that's why it was suggested to take a container and slowly fill it up. That level is the max it can obtain, ever unless the drain line is plugged.

08-30-2007, 09:58 PM
When I pour water slowly into the bowl, I add 2 - 3 inches before it stabilizes at its maximum fill point. It flushes everything out of the bowl OK, but because solid waste is too crowded in a smaller space when it doesn't fill to its design point, it doesn't clean as well. Surely there's an adjustment or a flapper that doesn't close so quickly, and allows the bowl to fill as much as it should.

08-30-2007, 10:29 PM
I think I found the answer to my question in another member's that was answered by Terry in a query titled "Toto Drake parts question".

I have an Ultimate model with a RED flapper. Terry indicates that the red flapper is for the Drake model, and the BLUE is for the Ultimate. Sounds like a common problem with an answer that s/b automatic -- once the model is determined! Does TotoUSA have manuals or parts lists that verify this?

08-30-2007, 11:25 PM
CST854, Ultimate, Blue flapper
CST854 Ultramax, Red flapper

ST743S Drake, Red flapper

06-29-2008, 09:44 AM
I have the CST 854 Ultimate and thought I was having the same problem as described in this thread.

I then filled the bowl up to the level it should be but after 5 or so minutes I started to hear the siphon start making noise and the water level had fallen about ~1 inch from the level it should be.

The flap seems to be sitting flush, but it appears as though water is draining out?

Although last night I manually filled up the tank and that didn't happen. People are mentioning there is an adjustment for this model, but I don't see one? Anyone have any ideas?


02-14-2011, 06:49 PM
I have the same problem. The water fills to the correct water spot size then drops back about an inch after about 30 seconds