View Full Version : what to use for bad seal surface for ballcock in tank?

12-30-2004, 07:10 AM
I'm replacing a noisy ballcock and I've discovered the hole in the tank for the ballcock is rather deformed. It was manufactured that way. Almost looks like a chunk by the hole was chipped out but the ceramic is fired with that defect. Anyway, the normal rubber donut at the bottom of the ballcock will not seal the hole properly. It looked like the original installer used plumbers putty to seal the penetration but it's been leaking recently.

My question is should I use the plumbers putty again? Or would I be better off to try and reform the opening with plumbers epoxy putty? Or should I just use silicone sealant at the connection? What's the commonly accepted way of doing this these days?


12-30-2004, 09:06 AM
You can use Silicone, but let it dry before filling the tank. I would give it overnight.

12-30-2004, 01:25 PM
If you use silicone, then you had better get the best fill valve you can find, because you may never be able to remove it from the tank afterwards.

12-30-2004, 01:33 PM
Well, there is that of course.

The last time I saw a deformed tank hole like that we wound up replacing the toilet.

12-30-2004, 01:49 PM
You could use some tape or wax paper, or plastic wrap around the ballcock, let the silicon set up, then take the ballcock back out, remove as much of the tape or whatever you can, then screw it together. You don't necessarily have to screw everything down tight while the silicon is setting up. Then, you'll be able to get it out. Some WD-40 on the ballcock might also work, but you might get some on the porcelain, which might mess up the seal for the silicon.

12-30-2004, 01:57 PM
Now you're getting close to why the toilet was replaced. The toilet tank was tiny, and the flush was poor. It even came with one of those "smart flush" things. You know we had to get rid of that thing.

12-30-2004, 07:44 PM
OK, I put a small bead of silicone around the hole. I put a bit more where the hole was deformed. Then installed the ballcock tube with the cone shaped rubber donut at the bottom and tightened the tube nut on the bottom of the assembly lightly on the underside of the tank. Also ran a small bead of silicone arount the outside perimeter of the base. When cured, I'll snug the tube nut just a little tighter. I guess I don't understand the concern about not being able to get this thing out in the future. I'm not talking epoxy here. Am I missing something?

12-30-2004, 07:50 PM
I wouldn't worry about it. Silicon is not only a seal, but an adhesive, too. It will bond the ballcock to the toilet as well as sealing it. If you don't do it right, you may have to break the ballcock out.

12-30-2004, 08:49 PM
Where we used to live, I repaired the toilet once with a kit. One of the things in the kit was a metal ring and expoxy putty to stick it onto the ceramic hole. That gave me a nice seal and filled in any imperfections in the ceramic. It then had the rubber stopper attached to it with a hinge. If I were you, I'd check for one of these kits.

Brian S.
12-30-2004, 11:00 PM
Is this a 1.6 gpf unit? If so, you may be better off just to get a new tank. If it isn't, this will at least give you reason to get a new high performance toilet such as a Toto, or any of the other toilets on Terry's list.

12-31-2004, 07:35 AM
Thanks guys! This is a 16 year old toilet that flushes just great. I really don't want to go to one of the low volume units required now. I'm going to let the silicone set for 24 hours before using it. I'll report my results after that.

Thanks again.

01-01-2005, 08:18 AM
Success! No leaks with the silicone. Thanks for all the input.