Tried everything I could think of to stop the leaking valve but no go so I decided to replace the Valve Cartridge with a new one. When I lowered the underpinning I found that one of the two belly bands for the black water tank was almost rusted through. Could ,not to find 2" wide strapping so installed three 3/4 inch standard plumbing straps instead. We hope this will be as strong as the original. The hardest part of valve replacement is working on the the underpinng/ belly covering. By the way we accidentally avoided a big smelly mess if the belly band broke while travelling.