Toilet bowl seal not holding water

Update - resolved. Replaced ball valve and seal. They sent the wrong instructions so had to figure it out on my own so took longer than anticipated. That said still straight forward. But if you ever attempt this, whatever you do, do NOT let the spring get relased from it's holding notches. Quite a booger getting that thing back on. All done, cleaner than it was when I bought probably, and back in holding water. $20 fix. No idea what the dealership would have soaked me for - pardon the pun. Thanks all for the advice.

Turn off water.disconnect water line. remove 2 bolts holding it to the floor.. lift off and place on workbench. Look in the back find the 2-4 bolts that hold the bowl to the base... separate.. take off old seals .. put new ones on... reverse process

I had tried everything except replacing the seals. Finally solved the leaking seal by multiple applications of http://www.marvelmysteryoil.com/.

That was 4 years ago , and the toilet bowl still holds water !

The kit should come with step by step instructions and diagrams. Mine did.

Update - tried all the methods listed in the replies. Thanks to all of you for your advice. I cleaned it, scrubbed it, tried the wire, soft scrub and vaseline. It holds a little better than before but still drains slowly. Guess I am moving on to replacing the seal. Anyone have sort of a step by step? Do I replace the black rubber as well as the plastic ball valve or just the rubber seal? It's a Thetford aqua magic II.

I did the tooth brush / Vaseline thing for half a season then finally decided to replace the seals. I couldn't believe how easy it was. Should have done that in the first place.

Years ago we had a tech come to our campsite to repair a chronic electrical problem. While there, I complained that our toilet would not hold water. He said to don a latex glove, turn the camp water off, hold the pedal down, put Soft Scrub on a finger of the glove and run it all around the rubber and over the 'closer'. Then put Vaseline on a finger of the glove and wipe all around the rubber. It ALWAYS works! You don't even have to use your wife's toothbrush! jim

mfinnerty wrote:
If you're careful, you can replace the seal in a Thetford without removing the toilet. I've done mine twice now.

Interesting, my Thetford Style II is needing a seal change. I think I will try that. Last time I replaced it I was thinking it may be possible to pull the seal out of the grove and slip the new one in using silcone grease for assembly and sealing as suggested in the standard install instructions. :)

Just need to not drop either seal into the abyss.... :)

I had a Sea-Land replacement toilet for about 3 years. For 2 of the 3 the thing just would not hold water.Sea-Land distributor did send me (free) a new seal kit AND a new flush assembly...to no avail. Replace, clean, I got pretty good at removing and re-installing the thing. But....got real tired of it real fast.

Last fall, CW had a sale on Thetford toilets. Bought one....so far...so good.

I didn't want to use mine.