Last nerve with vacu flush bowl seal

[discovery]

Our 22 year old vacuflush is driving me into the poor house..it's going thru a $50 bowl seal every 2 months.Ive been maintaining these toilets on my boat for 15 years and this is a new phenomenon ...Works fine until it suddenly is hard to depress the foot pedal and it won't snap back free..then it won't seal ..when I remove the seal the bottom Teflon ring has a depressed section in the forward part dead center..Somehow the seal is getting deformed by what I don't know.. this last time I put a new ball kit in a long with a new seal kit...great free snap back until today ...about 2 months in and it stuck and now looking down I can see the pucker...I tried to not tighten the big hose clamp to right left it as loose as i could without the toliet leaking around the ring....Even the head mistress is stumped..any one got a clue? I can't spend 250-300 a year on bowl seals

[gwalker]

Are you using certified Dometic parts? I know lots of people have tried to save a few bucks and buy parts off Amazon and have had issues. Unfortunately double the price but worth it.