Toilet not holding water

Here's a 4 minute video how to replace the seal on a Dometic 300 series. This is what I've done. Click here.


Here's a different kind of Dometic toilet: Click here.

And here's a Thetford video.

As said, need to know what brand and model of toilet.

We have the Dometic Porcelin 310/320 with the ball and seal. I have replaced the seal, and I have also rejuvenated the seal using boiling hot water, which was on an instruction sheet that came with the toilet. When you buy the new seal, buy a couplethree, because you will need them eventually. That is if you even have this model.

It takes an hour to explain it, and it takes 15 seconds to do it. Replace the seal around the valve slide hole in the bottom of the toilet bowl. Hold peddle down and the rubber seal just pulls right out. Clean the area with a toilet brush real well, rinse. Put the new seal in place, release the foot peddle and the seal with set itself. You may have to help it a little, but it basically will set itself.

I don't have access right now, but there is a very simple YouTube.com video some guy did where he explained it all. The video was like 15 minutes long, and actual time to pull and replace the seal was like ... 15 seconds. I'm not kidding.

For the short term, might want to get a small tube of "spa lube" (used for o-rings and seals on spa and pool filters) and lube the seal. Do NOT use vaseline, or other petroleum-based lube.

Lyle

My Sealand toilet was pretty easy. Disconnect the water line. Remove a decorative plastic cover from around the base of the toilet. Then there is a metal band holding the top portion of the toilet to the bottom. Loosen a screw in that band and lift the top portion off exposing the seal. Clean it all well and install the new seal. Make sure to align the center hole in the top to the seal on the base when when putting it back together. Not nearly as gross as it may sound.

There was a manufacturer plate on the base with the model number that guided me to getting the correct seal.

Yes there is. I have replaced the one on mine two times. Only takes an hour or less depending on how much I decide to "clean up". :B

Take a look here for lots of information and places to purchase new seals.

Click here for a PDF on how to replace the seal on a Dometic toilet.

Here is a source of manuals for many RV appliances kindly provided by one of our members.
Barney

Make and model of toilet would help.
Most with the slide valve can loose water because of small amount of debris in slide.
Thetford sells a bent screw diver to clean the area around the slide. You can make one out of metal coat hanged sized wire. Bend one end about 3/4 inch long tail at 90 degrees. Insert this into slide area and sweep around the seal area.