Thetford C4 issues

[Chilly]

This past weekend I discovered a slight problem with our cassette toilet: The valve blade no longer seals closed. The opener became hard to turn and now the blade will not seal the hole at the bottom of the bowl. I took the tank out and cleaned the mechanism as best I could, but still to no avail.
   It appears to be a problem with valve blade assembly, but I cannot remove it to find out. Is the tank able to be split open? If so, it would be a whole lot easier to see what I am working with!!
   Anyone else have a problem with this? Any input would be fantastic...Thanks

By the way, the cassette toilet is a Thetord Model C4 which apparently is no longer made!

[ForestCreature]

http://www.thetford-europe.com/web/show/id=51498/langid=42

Scroll down, there is a PDF file  repair for your cassette

[Chilly]

You know...I looked at that page twice and still missed it!! :swear: ...Thanks alot, I will try to take it apart tomorrow. Thanks again...Chilly