Gasket alone wont solve tank to toilet leak

[coolhl]

I HAVE TRIED THREE DIFFERENT GASKETS FOR MY TANK TO TOILET leak
but I think the problem may be pitting in the ceramic lip of the toilet where the
gasket sits when the tank is placed on top of it. Is there a sealant I can use on the ceramic lip that would keep a seal for years or do I need a new toilet. It cannot be sanded down. these pits are deep.
thanks

 

[Caduceus]

Maybe a little more history to your problem would help the forum members understand what's going on and how to advise you.
The "pitting" shown in your photo looks like slight imperfections from the original making of the bowl. Otherwise you would have no finish left inside the dimples if they happened after glazing and firing of the china.
When replacing the tank to bowl gasket, it is also important to replace the tank bolts and rubber washers with new parts, too. A leak from between the tank and bowl could also come from the bolts and give the appearance of a leaking gasket.
A fair amount of force is needed to get a good compression on the gaskets and under-tightening can be a problem with leaking.
This is all assuming that we are addressing the true problem. Tell us a little about what was going on with the toilet to inspire the repair project.

 

[coolhl]

I changed out all the bolts and washers...the cheap Chinese bolt/washer set from Lowes leaked but the commercial quality set I got didn't...
I am sure you are correct that the pitting was there from the original making of the bowl. I am not sure how it ever sealed for the 7 years it had been in use....I did apply quite a bit of pressure and I would imagine a tank full of water adds a whole lot more...everyone warnes not to overtighten so maybe I could tighten more after adding more pressure but the tank was nice and secure (didn't rock side to side). is that pitting enough to account for a bad seal? should I use RTV silicone between that lip and the gasket? If I do should I wait for the RTV to dry or assempble when wet? there were also ridges and imperfections in the inside of the tank where the bolt washers seal the holes and those I sanded down...
The toilet must be a cheap Chinese product like just about everything we get nowadays.
Thanks so much for your response!!!
norm

 

[frodo]

when you installed the bolts in the tank, did you put the rubber washer on the bottom of tank under the bolt?

picture of bottom of tank, and inside tank would help

 

[coolhl]

when you installed the bolts in the tank, did you put the rubber washer on the bottom of tank under the bolt?

picture of bottom of tank, and inside tank would help

bolt, rubber washer (inside tank),...... rubber washer, metal washer, nut (outside tank),........ rubber washer, metal washer, nut (toilet bowl).
I know I have the order correct....I just think either it is a defect in that inner lip , or I am just not apply enough, or perhaps too much pressure..


thanks,
norm

 

[Matt30]

Are the gaskets you are using a direct replacement? Or universal?

I've gotten some garbage universal ones and applied a small amount of pipe dope to the bottom to get them to seal up.

 

[frodo]

the way i tighten a tank, is till it stops moving, and level

also, things to look for, check the spud nut, make sure its tight,

also, the ball cock, next, if you cant find your leak, dump a bottle of red food color in the tank. if you have a crack in the ceramic

it will show up

 

[coolhl]

Are the gaskets you are using a direct replacement? Or universal?

I've gotten some garbage universal ones and applied a small amount of pipe dope to the bottom to get them to seal up.

universal: will try the pipe dope.....thanks,,,

 

[coolhl]

the way i tighten a tank, is till it stops moving, and level

also, things to look for, check the spud nut, make sure its tight,

also, the ball cock, next, if you cant find your leak, dump a bottle of red food color in the tank. if you have a crack in the ceramic

it will show up

will try the food coloring.....if the gasket was sealed properly would it still leak even if the spud nut was a little loose????
thanks

 

[coolhl]

Are the gaskets you are using a direct replacement? Or universal?

I've gotten some garbage universal ones and applied a small amount of pipe dope to the bottom to get them to seal up.

are you putting pipe dope on the part of the gasket that has contact with the spud nut/tank or the bowl lip or both...would silicone sealant work?

 

[frodo]

put pipe dope on the gasket, that mates to the bowl . and yes, if spud nut is loose it will leak...from tank to bowl, the ball cock will stay on

on the top of some bowls. there is a small "tit"/"protrusion" to keep the tank from setting down all the way onto the bowl.
I have seen, garbage spud washers, that were so thin, they would not seal because of the spacer/tit/protrusion

 

[Matt30]

are you putting pipe dope on the part of the gasket that has contact with the spud nut/tank or the bowl lip or both...would silicone sealant work?

I put pipe dope on the bottom of the gasket that makes contact with the bowl. I wouldn't use silicone. You gotta wait for it to set up and it just makes a mess trying to take it apart later if it needs service.

Ideally I woulnt use anything at all though.

 

[coolhl]

Turned out to be a long but barely visible hairline crack in the back of the tank. Took a real plumber two minutes to find it. Thanks for all your input.