OEM Toto CST854 Flapper

[Vince DR]

hello.

I have three Toto CST854 elongated toilets where the flappers are at the point where they are hanging on by a thread. Because the toilets were there prior when we moved it I am unsure what the part to replace the flapper is. I managed to find the following:
http://www.korky.com/flappers/genuine-toto-3-universal-flapper

The flapper should be relatively easy to replace as long as I follow the instructions right? What I am finding now is that water is seeping between the flapper and 3" hole very slowly to the point where the water level will eventually go below the fill line and the tank will add more water.

Is this the case where I need to find the exact OEM part?

**some troubleshooting
I've allowed the tank to fill and closed the water supply at the shutoff valve. I want to determine if it is the flapper or the flush valve.

Emptying the tank water up to the level where the flapper and the flush valve meet and I let it sit overnight the water level did not drop past the top of the flush valve, so the issue is the flapper right?

Thank you in advance.

 

[Reach4]

Is this the case where I need to find the exact OEM part?

No.

See http://m.korky.com/landing.php to help select the part.

Clean the seat with a cloth. You can do this before trying the new flapper or while changing the flapper.

 

[Sponsor]

 

[Vince DR]

thanks for the reply.

I went on the part selection website and it is really helpful... I have purchased 2 of the 3 recommend with the same result.

As per your comment, which seat are you referring to please? I may not have all my terminology.

thanks again fro the reply

 

[Terry]

"Emptying the tank water up to the level where the flapper and the flush valve meet and I let it sit overnight the water level did not drop past the top of the flush valve, so the issue is the flapper right?"

Yes, it appears to be the flapper.

 

[Reach4]

As per your comment, which seat are you referring to please? I may not have all my terminology.

The flapper drops into+over a hole. The contact area is called a seat. I would take a damp cloth and wipe away any possible debris. You can also feel for a burr; the seat should feel smooth.

If the new flapper does not cure the problem, it is possible that you would need a new seat. That is a fair amount of work to replace. Also, it is rare but possible that there could be a crack in the overflow tube.

You could wipe the seat with a light coat of silicone grease, but that is not a common thing to do or need.

 

[Vince DR]

thanks Reach4 and Terry.

The flush valve is the plastic ring that meets the flapper right? I've checked to make sure that it is smooth and that there is no debris, cracks etc. Is the flush valve supposed to have any kind of rubber gasket or something? Because it is just straight plastic. the flapper would to have fit perfectly over the flush valve. At this point, i've tried a few flappers and cleaned the seat of the flush valve and I've checked to see if the overflow tube has any damage. Is there anything else I can do? would you recommend a flush valve repair kit if if the flush valve is the problem
http://acehardwaremaldives.com/product/plumbing/43505/#.Vjzsk7erSM8

thanks again for responding

 

[WJcandee]

Check the chain length on your new install. There should be one link of chain loose on top of the flapper. If you have too little, sometimes the flapper ends up sitting imperceptibly above the flush valve seat. Too much, and it will hang up under the flapper lip.

The water pressure presses the rubber of the flapper against the hard plastic, forming a seal, so no need for a rubber piece around the lip of the flush valve.

A new flush valve is easy on the Ultramax. Unlike a two-piece, where you need to remove and reinstall the tank, here you just turn a couple of screws and lift it out from inside the tank. However, I would mess with it more before going that route. Also, no chance of a leak between the flush valve and the porcelain below it? I.e. flush valve isn't properly screwed down?

You can post a pic of the inside of your tank and we can often see stuff right away that's wrong.

You don't have the refill hose just shoved into the overflow tube, do you? It should be mounted on a little clip above the tube so it's above the water level in the tank.