On a recent trip I had an issue with my fresh water, specifically how much I had available. By my calculations I was 30 gallons short on my actual capacity. I talked about that in this thread. Something's terribly amiss here.
Well I decided to fix it myself. Yes, the unit is under warranty but A: My dealer is incompetent and wouldn't repair it properly. My last service visit proved that. B: They're 80 miles away, the next closest Forest River dealer is another 100 miles. I'd burn more in fuel hauling it there than it cost me to fix it.
I pulled the tank out, saw that the tank itself is fine if flimsy. I'll look into a bigger tank one day maybe, there's room to work with.
I straightened the frame work, then added a piece of angle iron welded right onto the existing frame to reenforce it. I noticed that the tank was actually sagging between the ladder rungs so I added some 1" square tubing between the rungs with a thin sheet of plywood on top, now the tank can't sag through and is supported. I noticed that the corner of the tank that has the drain and the supply line for the pump was actually higher than the rest of the frame so I dropped that to be actually 1/2" lower than the rest of the tank.
One side of the frame is hard welded in, on that side the ladder rungs just sat on top of the angle iron, no attachment at all. What I did last was weld in some iron tabs, drilled through the rungs and added 5/16" bolts so that now the frame is actually one piece. It's so strong now that I'm pretty sure the tank will split before the frame gives again.
As for prevention, I used a ball valve and two water hose adapters, I put that between the water hose and the fill connection, when I test filled it I let it run full flow until it was running out the vent then closed the valve until the inlet flow was less than the vent flow, until water was trickling out instead of actual pressure. Marked the valve position and from now on I'll set the valve there and just walk away while it fills. Might take an hour or more to fill, but I'll be busy doing other things.
Sorry, but only a before and after photo. I might be a photographer, but I'm awful about taking photos during my projects.
Before. You can see the factory angle iron that bent allowing the tank to fold like a taco. That water? That's with the drain line completely dry. That's how high the sides of the tank lifted up.
After. You can see the braces between the cross braces I called ladder rungs, also the tabs I welded to bolt it all together. After this shot a little cleaning and black paint makes it pretty.