Internal waste valves, 25FB

[TDA]

We are looking at new 25FBs for future purchase. Having just replaced both waste valves in my 23 year old SOB for the third time, I am curious about the 25FB's "internal" valves. Both grey and black valves are operated by cable or rod from the area of the sewer discharge line, just forward of the left front wheel. Sales person says the valves are inside the tanks, which is difficult to believe. I suspect they are outside the tanks, but above the belly pan. So, what exactly are they (brand/style), and where are they? How does one go about gaining access to replace seals or whole valves?

[RichHog]

I have a 2006 25’ FB Safari. Never had problems with the valves. There’s a rod on both tanks that you unlatch then pull out. Don’t think they are inside the tanks, black PVC extends to the side of the trailer.

[CRH]

They are outside the tanks above the belly pan. My trailers owners manual tells you their way to replace the valves is to cut a hole in the belly pan, do the work and make a cover plate. That is exactly what I did. The valve to tank adapters for both valves cracked at the 20 year mark. My trailer has Thetford brand valves.

[Julie-Bob]

All wast valves are out side of their tanks and are inside the pan. They are controlled by push pull rods and if they are AS valves are Thetford Valves. They are changed by cutting a 18” by 20” hole in the pan.

[Adventure.AS]

Newer 25s have waste valves outside the belly pan. Perhaps Classics have enclosed valves.