[VAC] Holding tank valve seals?

["Tim Cook" <timcook@xxxxxxxxxx>]

I have a 71 25' Trade Wind and am having some problems with the waste tank
valve seals leaking.  I can see where it looks like the seal has deformed
and part of the lip has come down enough to stop the valve from completely
closing.  Does anyone know if these seals are replaceable without removing
the entire unit?  It doesn't see like a very easy job to replace the whole
unit.  I wonder if the seals are still available?  I am going to call
Airstream, but wanted to check on the list for some first hand information.

thanks
Tim
71 Trade Wind