While researching how to replace a knife seal that is leaking on our 15 year old porta potti ( really a Packa Potti 6000 - Sears Porta Potti line). I came across this "how to" 44 page pdf doc. I know there has been several posts on replacing parts in Porta Potti's so this article might come in handy.
I am ordering a new $6 seal today. NOW has anyone actually replaced this seal (bottom of page 4 of above referenced pdf) and if so do you have any tips on doing it???
Replaced both the lip seal and the bellows pump on our Porta Potty. Project took less than 45 minutes. Interesting that the original bellows lasted 11 years and the replacement I put in 4 years ago only lasted 4 years before splitting. Anyway a new one is now installed. Total cost for both less than 20% the price of a new similar model toilet.