Toilet

Had the very same problem 2 weeks ago on a dometic 310. One application of spa & pool lube took care of the problem

If it is a Thetford AQUA MAGIC it is a bad design and you can try and lube it all you want but it WILL fail.. CHUCK IT!! I have had 2 pedals break or malfunction on mine and flooded the bathroom twice replaced it with a Dometic 310 high profile and have piece of mind and also 2 of my buddies have had the same thing happen to their Thetford

As suggested, I applied Plumbers Grease with a Q tip to the ball and seal. Viola, closes fine now. I previously replaced the entire assembly twice, only to start seizing up again.

Thanks guys. This is why I love this site. A wealth of info.

guess it dep0ends on the toilet. On my sealand you can hold the ball open and just reach in and pull the seal out either to clean it or replace it.

Also I have switched to plumbers grease for lube.

think you have to figure out if the ball is binding or your spring mechanism is bad

Check spring pack may be broken.

Hope the above process works. If not - can it close if you lift the flush lever up? If so then the flush lever mechanism is out of whack. It happened to me when I stepped on the lever too hard. I couldn't see anyway to adjust it back so I just bought a whole new toilet. A "high rise" model. I like the new one a lot better. Good luck.

I use plumbers grease as lube when mine gets sticky. It is available in small tubes at hardware or home supply stores. Use your finger to rub it on the rubber seal.
Brian

It's just what you think-hold it open with water off and use an old toothbrush to clean the ball and seal.
Dirty job but sorry no magic will fix this .
Good Luck, Mike