TOILET>>>>

Yes...there is a seal.
Try cleaning it first and the grove/track that it goes into when closed. Might try something like Vaseline on the existing seal also. Maybe just some debris/toilet paper..but.

If this fails you will have to remove the toilet and replace the seal from underneath or by taking the toilet apart...That's what I had to do. RV dealers have the part...also on line.

Not all that difficult (and not all that much fun either).
Google your toilet brand and model and you can download the step by step instructions..There are also videos on youtube.

Good luck with it.

What he said it usually is just some toilet paper stuck where the blade hits. Open the blade and run a brush around that area first then push the pedal down and release your foot real quick and let it slap shut a couple of times. It's what works for me even before using the brush step. I hope that is all it is. Replacing it IS a dirty job but someone has to do it! :B

This is why I've always used a little bottle of "toilet seal" preservative. Without checking my RV at the moment (in storage), I believe I buy Thetford brand at camping world or Wally World.

I use it year round with just a splash of water. It keeps the seal moist during storage and it never gets stuck from sitting dry in hot climates when your not using the trailer.

It's designed for toilet seals and will not crack the rubber seal. I'm not sure, but I believe it is NOT petroleum based. Many rubber products crack with a petroleum based oil or grease. Not sure what your rubber gasket can handle, so the solution specifically made for toilet seals is probably better for most than Vasoline or grease.