try again to adjust the chain on the flapper, you did it right on the others, you can do it with the other two.

I replaced a soft plastic flapper with a hard plastic per recommendation and still leaked, found another soft one and that fixed it.

Make sure the water stays below the top of the overflow tube.

Clean the seat where the flapper rests on.

ctbosox, when you say adjust the chain, do you mean take the slack out of it? I have all 4 set on the same link with a little slack, but not much.

hendricus, I felt the seats for the flappers and didn't feel any rough edges or debris, but I didn't scrub them. I'll try that just in case.

I have the water level set about an inch below the top of the overflow tube on all the toilets.

on the chain, just didn't want you to have it too tight so it couldn't seat right. sometimes the chain is so long that if you don't snip off the extra it gets caught under the flap. I would still stick with the flap theory first, although the flush valve could leak, I've almost never ran into that.

I really want it to be the flaps, but two of the toilets show zero improvement after replacing them and the rapid flow of dye into the bowl doesn't bode well, does it?

Where should I go next?

If anyone has a suggestion for me, I'd love to hear it.
Thanks.

I bought numerous different flaps for one toilet b4 finding one that didn't leak any at all. I tried the chain in all different ways too. I just assumed they were defective, or out of round a bit. I tried different brands.

I could easily see just a very little bit of water movement at the back of the bowl when they were leaking.

Maybe switch out a flapper from a good toilet and put it in a troublesome toilet. then you could safely assume it was the flapper if the good one happens to correct the problem.

I bought a kit to replace the entire valve, which involves a sticky rubber gasket to glue a new valve down over the old. I'm hesistant to install that.
I've never seen any glue involved with the replacement of a flush valve...but maybe mine is more typical than yours. If yours is just a typical one, I'd just take the one back that requires glue and get a different one. The last one I changed was all pretty well finger tightening of things...if my memory serves me correctly.

I too won't pay a plumber if it is something simple that I can do myself.

Sue

I still want to go with the flap, maybe someone else can chime in here. Take the top of the tank off and watch as you flush the toilet to see what is happening. Not saying you arent' watching, just saying to pay careful attention. I've seen where the handle is out of line, got bent or is rubbing on something to effect the flap seating properly. I really feel something is keeping that flap from seating properly. Also, what type of flap do you have? could you give a description of it.

Sue, what you are describing in your toilet sounds exactly like my situation.

So I poked around in the tank a bit more last night. Scrutinized the process and I don't see anything amiss. Nothing's catching or rubbing or skipping. As soon as the tank is done filling I can hear the trickle sound of water leaking, though, and it never stops. When I reach in and push the flap down harder, the trickling stops. After I release it the seal seems to hold, so maybe this is just a flap issue (I'd love that).

When I bought the replacement flaps I went into the local Mom & Pop hardware store with my old flap in hand and told them I wanted the best they had. I ended up with bright red Korky flaps.

Since holding the flap tighter seems to stop the trickle, should I just start buying different ones to try, or is there something else I can do to increase the seal?

it sounds like a flapper problem. Although a replacement flapper may look exactly like the original there can be a very slight difference that will let water leak. Measure from the center of the eye (hole)that the flapper mounts on the overflow pipe to the center of the sealing part of the flapper. You will find that there are a couple of different sizes...very slight differences like 1/8" or 1/4". If you have the wrong size the flapper will not drop into the center of the hole and will leak.
Hopefully you have not thrown the old ones away yet so you can get an accurate measurement.
Since it sounds like you might have 4 different toilets, checking the ones that aren't leaking might not help. Anyway there are only 2 ways that water can get from the tank into the bowl..the fill level being too high and water going over the top of the overflow pipe or water going under the flapper. The symptoms you are describing sound like a flapper problem.

You are wise to try and solve this problem. I have worked for a company that repaired water damage and saw the results of a leaking flapper. Someone used the toilet just before the family went on vacation and clogged it. Because the toilet flapper leaked, the tanks filled and emptied the whole time they were gone. When they came back, most of their carpet was ruined and the ceiling had come down in their kitchen. Their insurance paid for new carpet and a new kitchen, but I imagine that not everyone with this problem fares as well.

You need to reliably fix this. If your efforts with replacing the flappers are not working, then consider replacing the toilets. I realize that replacing a flapper cost only a few bucks and that replacing a toilet cost much more, but replacing a toilet can be a DIY project. You can buy some of the best new toilets on the market for a little over $100. They flush better and may use less water than the ones that you are replacing and sometimes the local water companies have rebates available that can help. Good luck!

Roland

Sorry I haven't updated this in a few days. I wanted to let you know that I followed all your "it's got to be the flapper" advice and headed back to the hardware store. I bought a completely different type of flap ~ this one is rigid plastic with a rubber ring that meets the seal, and it's much heavier than the flimsy rubber Korky flaps. They only had one in stock, but it instantly stopped the leak in the toilet I installed it in. The relief was enormous.

Tomorrow I'm going back to specifically ask them to order more for me.

Thanks for all your help, everyone. I really was ready to throw in the towel and call the plumber.

congrats to you for your determination, calling the plumber isn't a bad thing, just sometimes you like the satisfaction of fixing the problem yourself.

Sarah,

I just came back to check on you and see if you got the problem solved. Congratulations! I hope DH was proud of you and the money you saved by doing it yourself.

Sue

Sarah, Coming in late on this.... can you post the brand of flapper that worked. I have a toilet doing what you describe, have tried many soft flaps w/o success. Oh, and where did you buy it?? Tx, Mike