I have a Thedfod 31112 toilet. When the blackwater tank was overfilled,it leaked from the the floor seal. I've had this problem in the past. I have three questions: 1. Should that seal on the floor prevent water from leaking when it gets over full? Or is that gasket just to prevent odors to come up and not seal from water leakage? I've had this toilet out about 4 times for various reasons and replaced the ring with a new one every time.2. When i install the toilet, I cannot feel any compression, or seal betweenl the toilet and the ring. Could the flange be so high that it prevents the toilet from sealing? 3. If the flange is to high to prevent the proper sealing, can I find a thicker gasket to compensate? The flange on the tank is glued in, so it cannot be moved. Thanks for any and all suggestions. I've searched online and cannot find anything about finding a thicker gasket, although I thought I did read about someone somewhere getting one from a plumbing wareeshouse.Brad N. Myrtle Beach,SC

I’ve had the same problem…So I whittled down to fit snd installed a convention wax ring (i.e. wax only-no plastic) to supplement the O-ring…3 tons

draboo wrote:The flange on the tank is glued in, so it cannot be moved. Are you sure it is glued in?One of my first posts on this forum, if not my very first one, was asking how the toilet flange came off. I think some said it was glued in, but others told me it was threaded.On mine I think there were a few screws into the floor. After taking the screws out, I used a blunt drift punch and a hammer, rotated the flange counter clockwise out of the tank. It came out very easily when I knew how.I suggest you try that, and replace the flange with a new one, checking the size and clearances etc to ensure you get proper compression on the new gasket.Also check the bottom of the toilet for any irregularities. Put a small straightedge across the outlet, moving it side to side and rotating it to make sure it is perfectly even right across and not warped.

I avoid going much past 2/3, I don't want sudden braking to cause a spill.I recently changed the flush valve on my Thetford. The kit came with a new gasket, which I used. I found the gasket easily moved off center, and it took several tries to get it right. I had to open the valve and look down the throat to see if the gasket was even. You should be able to see the extent of gasket compression in a similar manner.

I am not a fan of wax rings in an RV, as normal going-down-the-road vibration can cause gaps.Better are the silicone or other compressible gaskets that work with the motion of the rig.And, none are designed to hold against PSI from an overfilled tank. For pete- sake, drain it before it gets that full!

The last incident was caused from "friends" who we allowed to stay in the motorhome.that didn't follow instructions. So I had to rip out the flooring, dry everything out for a week, and this week am having sheet vinyl installed again. I'm confused about how well of a seal that rubber/foam ring provides. And if you can "feel" the ring compress when you install the toilet before you tighten the bolts. I put the toilet back down temporarily today and I couldn't feel the ring compress when the toilet was sitting but not bolted down.

Trouble with leaking around toilet flange | Good Sam Community

JJnLilly
Explorer
Aug 13, 2021
The WC flange is glued to the ABS pipe that connects to the black tank. Ended up epoxying the broken piece and then used a "repair" flange over the entire WC flange. Seal between toilet and flange was fine, but replaced it anyway.
John_Wayne
Explorer II
Aug 09, 2021
On a friends MH his toilets pipe fit in the black tank with a ring gasket it was not glued into the black tank. The ring on his split and he had to install a new one. So if yours over flowed and didn't come into the bathroom area just over the black tank it may be the same.
RLS7201
Explorer II
Aug 09, 2021
When I mounted our commode, it didn't touch the floor until I tightened the bolts, which compressed the seal. I intentionally over filled the black tank, until it flowed into the commode with the flush valve held open. The seal did not leak.
Maybe you could use 1 1/2 or 2 seals glued together.

Richard
JJnLilly
Explorer
Aug 09, 2021
Toilet in our unit began to wobble so when got home did the deed and removed it and found the mounting flange was broken. Flange is glued into the black tank so no real way to just r&r the flange. Looking for a good way to repair
draboo
Explorer
Jun 21, 2021
3 tons wrote:
draboo wrote:
The last incident was caused from "friends" who we allowed to stay in the motorhome.that didn't follow instructions. So I had to rip out the flooring, dry everything out for a week, and this week am having sheet vinyl installed again.

I'm confused about how well of a seal that rubber/foam ring provides. And if you can "feel" the ring compress when you install the toilet before you tighten the bolts. I put the toilet back down temporarily today and I couldn't feel the ring compress when the toilet was sitting but not bolted down.

You won’t feel it compress - I’ve never felt mine compress, the O ring seems only minimalist-ornamental to me - trust that this malady is uber common…

3 tons

Thank you for your response. I'm finally done searching. :)
3_tons
Explorer III
Jun 21, 2021
draboo wrote:
The last incident was caused from "friends" who we allowed to stay in the motorhome.that didn't follow instructions. So I had to rip out the flooring, dry everything out for a week, and this week am having sheet vinyl installed again.

I'm confused about how well of a seal that rubber/foam ring provides. And if you can "feel" the ring compress when you install the toilet before you tighten the bolts. I put the toilet back down temporarily today and I couldn't feel the ring compress when the toilet was sitting but not bolted down.

You won’t feel it compress - I’ve never felt mine compress, the O ring seems only minimalist-ornamental to me - trust that this malady is uber common…

3 tons
draboo
Explorer
Jun 20, 2021
The last incident was caused from "friends" who we allowed to stay in the motorhome.that didn't follow instructions. So I had to rip out the flooring, dry everything out for a week, and this week am having sheet vinyl installed again.

I'm confused about how well of a seal that rubber/foam ring provides. And if you can "feel" the ring compress when you install the toilet before you tighten the bolts. I put the toilet back down temporarily today and I couldn't feel the ring compress when the toilet was sitting but not bolted down.
wolfe10
Explorer
Jun 20, 2021
I am not a fan of wax rings in an RV, as normal going-down-the-road vibration can cause gaps.

Better are the silicone or other compressible gaskets that work with the motion of the rig.

And, none are designed to hold against PSI from an overfilled tank. For pete- sake, drain it before it gets that full!
stevenal
Nomad II
Jun 20, 2021
I avoid going much past 2/3, I don't want sudden braking to cause a spill.
I recently changed the flush valve on my Thetford. The kit came with a new gasket, which I used. I found the gasket easily moved off center, and it took several tries to get it right. I had to open the valve and look down the throat to see if the gasket was even. You should be able to see the extent of gasket compression in a similar manner.
BobsYourUncle
Nomad
Jun 20, 2021
draboo wrote:

The flange on the tank is glued in, so it cannot be moved.

Are you sure it is glued in?

One of my first posts on this forum, if not my very first one, was asking how the toilet flange came off. I think some said it was glued in, but others told me it was threaded.

On mine I think there were a few screws into the floor. After taking the screws out, I used a blunt drift punch and a hammer, rotated the flange counter clockwise out of the tank. It came out very easily when I knew how.

I suggest you try that, and replace the flange with a new one, checking the size and clearances etc to ensure you get proper compression on the new gasket.

Also check the bottom of the toilet for any irregularities. Put a small straightedge across the outlet, moving it side to side and rotating it to make sure it is perfectly even right across and not warped.