Leaky Toto Carlisle Toilet (Something is Wrong!)

[Roback]

I have two Toto GMAX system toilets, a CST 854S, and a CST874S. Both toilets have been in service for about two to three years. Both are running constantly, however, initially after flushing they are quiet for a couple of minutes after a bit of soft gurgling, and then intermittently becomes quite and goes back to creating noise. I drew a pencil mark at the water level, turned off the water and let the toilets sit for an hour or two. There was a drop in water level, so I figured it was the flapper, and proceeded to replace with a new original equipment flapper, model THU175S. By the way, which hold in the trip lever is best to attach the chain to, and what is the little white plastic tube that comes on the chain with this unit? Do I throw it away or leave it on? No dice, still happens. Although, new flapper seems to be creating a nice seal! I took the cap off of of the GMAX system to watch it work in action. Flush toilet, watch the water raise and the shut off on the GMAX system raise until the water is stopped and the noise seems to go away. If I let is sit like that and watch it, approximately two minutes or so later, a small stream of water starts shooting out of the top of the GMAX system. The only way to stop this is to flush, or shut the water supply off. I am not familar with adjusting the GMAX system, YET, so I do not know what to do? Odd that the same thing would be happening in both toilets. This is a hard water area so perahps there is some deterioration to the plastic/rubber components? Any help that anyone can offer would be appreciated. I don't think it could hurt to have replaced the flappers, although it has set me back about $35 so far!

 

[Roback]

Update - Cleaned Valve No Dice

Just as an update, I downloaded schematic to clean the GMAX valve. Took out the float, diaphragm, strainer tube and rinsed all under hot water and went over teeth with a toothbrush! I cleaned the white check ball at the bottom of the float chamber. The only thing I did not do was to clean the rubber diaphgram seal with a surfectant like soap. Perhaps this is the culprit? I am in a hard water area, so I wonder if the rubber seal in the diaphragm needs to be replaced. Can the diaphragm be purchased by itself without having to buy the whole darn fill valve? Does it seem from what I have described that this rubber gasket could be the culrprit? I am stumped! Please help if you can.

 

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[Terry]

Lowes sells the assembly cap for $2.47, under the Korky QuietFill brand.
They also sell the flappers for $9.99

This is the original TOTO flapper

 

[Roback]

Assembly Cap?

Is the diaphragm cap the same as the assembly cap? Is this a likely culprit?

 

[Jadnashua]

The cap helps work to stop the valve from running; it won't help if the water is leaking from the bowl. Turn the water off, flush the toilet, then rub your finger around the flapper valve seat to ensure it is smooth and not contaminated with something.

Make sure that the refill hose is not down in the refill tube or it can siphon some water out.