Any chance there is blockage in the drain line? You could run a garden hose full blast down the hole to check for that.
Does this leaking occur only when you flush? If not, the leak could be from under the tank.
That doesn't seem right, but if you need more compression/thickness, use the black thing you removed. How much higher does the top of the blue sit higher than the floor with the toilet off?
The toilet could have a defect. I am not saying that is likely.
What caused you to start this project? Rocking toilet?
Thanks for your questions and the time you took to carefully think them out. I'm impressed. My answers are as follows:
Q. Any chance there is blockage in the drain line? You could run a garden hose full blast down the hole to check for that.
A. Not likely but I cannot rule that out. No problems with leakage with the prior toilet that was installed until three days ago, but the conditions now are different, i.e., I purposely tore/removed the broken part off of the original flange, installed a spacer on top of it, and installed the FluidMaster on top of that.
Q. Does this leaking occur only when you flush?
A. No. I left it alone for a few hours and came back to find a very small trail coming out the right front of the base. I wiped up the trail, left it for another few hours and found another trail. So it's just a very slow leak.
Q. If not, the leak could be from under the tank.
A. Where under the tank could the source of the leak be other than through a gap I have inadvertently left between the horn and the Fluidmaster?
Q. That doesn't seem right, but if you need more compression/thickness, use the black thing you removed.
A. That's what I thought. I asked about that, but the Fluidmaster phone rep said to use two of the blue things (by buying another). I'm tempted to do that just to see if it works. I would welcome an $8.00 fix. Or, maybe a $3.00 messy wax ring would do the trick. I just don't have the knowledge and experience with plumbing to make a competent assessment of problem and solution. I thought I had the solution until the slow, thin trail of water appeared.
Q. How much higher does the top of the blue sit higher than the floor with the toilet off?
A. The spacer sits about 1/4 inch or just slightly higher off the floor. The blue thing sits probably another 1/4 inch to 1/3 inch higher than that. I really can't recall about the blue thing since right now it's under the toilet. But won't be in about twelve minutes when I remove the toilet again.
Q. The toilet could have a defect. I am not saying that is likely.
A. It may not be likely but it is possible. It's a second-hand toilet I just got. Owner claims all is good with it; I don't think he would lie, but he could have. He's doing a remodel and is getting rid of two of them and giving me the second one soon. He claims his young son covers his ears and gets scared every time either is flushed. The one at issue that he already gave me is a Gerber 21-377 or 21-372 (both numbers are oddly stamped on the bowl) mated with a Gerber 28-380 tank that is installed with a Flushmate 503 pressure-assist unit. The Flushmate 503 was attractive to have and that's why I swapped out the one I had for it. (I looked up the Flushmate serial number and it was not on the recall list.)
Q. What caused you to start this project? Rocking toilet?
A. Yes. It wasn't a serious issue, but the house inspector caught it before move-in and told me the flange was likely broken. I wanted to take care of it before it became an issue. And, installing the Gerber with Flushmate seemed like a fun and simple learning project whilst repairing the broken flange. Three days later . . . boy, was I wrong.
