Tuesday, December 18, 2012

Replacing a Thetford toilet seal–One Crappy Job!!!


Tools Needed:

  • 1/2 inch closed end crescent or adjustable crescent
  • pliers
  • 3/8 inch open ended crescent
  • small rounded scraper or flat head screwdriver
  • small bowl
  • lots of rags

The model of Thetford toilet I have is a 34420 or also known as the Style Plus version of the Aqua Magic toilet. About a month ago we noticed that the toilet would slowly leak water seal beforefrom inside the bowl. Everything I read on line after searching for “water leaking from Thetford RV toilet bowl” came to the same conclusion. The solution must be that some debris (I assume that meant toilet paper and not that other stuff) was stuck somehow and it was keeping the seal from completing. Most of the comments online suggested the debris was stuck in the “blade”.

Well we scoured the area just around the seal inside and out and it seemed to work… or did it? Nope the water began leaking from the bowl again and so I took pictures of the label in the back of the toilet (since I couldn’t read them any other way) to determine the type of toilet I had. I verified this information with Thetford by calling their 1-800 phone number and they gave me the link to the exploded diagram of the toilet (something about exploded and toilets that didn’t leave a nice visual in my head, errr mind).

imageAfter scrutinizing the diagram it was apparent to me that my particular toilet had no “blade” so I must have a different problem. No blade to me meant no stuck debris but it did mean to me that my bowl seal might be bad. There is a rubber seal between the top and bottom halves of the toilet right where the water must go down. I couldn’t tell if the seal was bad but there was a lot of hard water buildup around the seal (at least I hoped that is what it was). So I ordered a new seal for the bowl and a new seal to replace the old seal between the toilet and the floor. It is recommended to replace both at once and why wouldn’t you since the toilet has to be removed anyhow.

I bought the seal kit from Ebay for about $16.00 and it also included detailed instructions for replacing the seals. First I dumped the black water and back flushed it. Then I removed the nuts holding the toilet to the floor and then moved the whole toilet outside. I brought a garden hose inside and took the opportunity to blast (another scary toilet word) water into the holding tank to give it a real good cleaning. Once finished I placed a rag over the opening to keep the gases from escaping (there I go again).

There were four nuts holding the top half of the toilet to the bottom half. Once removed I noticed the seals were real bad and that there was a ton of buildup on the the ball seal from all the hard water we encountered. So using a small screw driver I very carefully used its edge to slowly and carefully scrape the hard water deposits from the entire assembly. Once it was cleaned up I rinsed and dried everything and placed the new ball seal on the bottom half of the toilet.

imageI put the top half down ensuring that the bolts were properly aligned and that the top half was fully seated onto the bottom half. I tightened down all the nuts (not too tight as you don’t want to crack the porcelain. I replaced the old seal at the bottom of the toilet and placed the bowl over the two securing bolts on the floor.  I then tightened down the two nuts securing the toilet to the floor and reattached the two hoses in the back of the toilet. One had a PVC screw-on attachment so I placed some Teflon tape between the threads (highly recommended).

imageI turned the water and hoped nothing would leak.  When it appeared I was safe from any poor plumbing skills I flushed the toilet and viola!!! it works as it was supposed to again. The whole process took about two hours as I was cautious about removing all the hard water deposits. But for 16 bucks we have a nearly new toilet…

This was an easy job for a do-it-yourselfer but I have to admit as crappy as the job was, once finished no one can say, “You don’t know shit!” anymore…


  1. Ha ha !!

    At least you kept your sense of humor !!

    Thanks for the smile ... TnT

  2. If I ever have toilet problems, I'll be hunting you down since you are now an expert! :)

  3. You're right, that was definitely a crappy job.

  4. Sounds like everything came out fine!!! Goody for you.

  5. Good job- these darn rigs are so complicated I feel it is a big victory when I can fix something myself.

  6. LOVE your last line. We had the leak problem, David replaced the seal, we still had the leak problem. :-(( Glad it turned out better for you.

  7. Thanks for the instructions :) Ours is doing that same thing. I'll have George read this!

  8. Good job! And, you didn't even need a paddle!

  9. Good Job and GOOD BLOG!! Hopefully this will help me and others down the road faced with a similar "crappy" job. How did you like working in those tiny RV bathrooms :-)


  10. Great sense of humor for a ... dare I say ... 'cra**y' job! Post for this link goes to the handyman in our rolling home.

  11. Good job on the toilet, did ours a couple years ago, it had the blade, and hard water buildup on them was keeping it open. Has been working great ever since!

  12. Thanks for this post!! We paid to have ours redone last year, but it looks like something we can/should do ourselves. Our problem also was hard water deposits. Just last month I decided I'd had enough, and purchased a marine/rv water softener that hooks up to our water line. Now the toilet stays clean and no more crusty hard water buildup! -- Dianne

  13. We had to replace the flapper ball and giant o-ring seal this summer. The seal was SHREDDED, not just a bit blocked. The tech who did the replacement lubed it with Sil-Glyde from NAPA (part 765-1351). We bought some and are glad about that. We re-lube the toilet seal every dump. Turns out that Sil-Glyde is far superior to any "grease" used on the coach. We lube anything that needs a sticky, gooey lube, such as the compartment door latches. Regular white grease just melts away, this stuff STAYS. Also, unlike vasilene, the silicone stuff does not degrade rubber.