[BusNit]

I have replaced my black tank plumbing in favor of a heavier duty dump valves. The original on my coach were Thetford with the non standard 2 hook clamp. At one point there had been a tank leak in the previous owners possession. They had it fixed but it seems the water damage had leaked under the fiberglass bay liner and on top of the steel chassis floor. The water had no where to go so it ate all the metal away. It was very well hidden under the spray foam. I am at a loss in dealing with something I was not expecting. Seems like one step forward and two steps back. I was excited to upgrade the plumbing and added a hose connection to wash out the sewer hose. How I discovered the rotted mess underneath is from the water tank bulging and bending the support that was installed. When I checked the support, it was loose and flexed. This told me the anchoring bolts were not doing their job. I dug the foam around them only to discover the rotted mess of earthy brown decay. I am not going to pull the tanks but instead scab some galvanized 12 gauge plate between the 1.5" square tubes once I clean off the rust. The foam did a good job of keeping the water hidden until it was too late where it then found a path through the protruding bolts. Still wondering how the water got there. All seams are well sealed.