I think you are going to have to take a closer look at the leak, in order to ascertain its leak's exact nature and scope. My impression is that the tank material is difficult to weld/patch, but if you can install a larger new drain valve with the appropriate backing plates/washers, and use a magic sealant (or rubber gasket -- like a sink drain sealing gasket), you might get away without replacing the tank IMO.
The best help I can give may be to suggest some search techniques for locating other threads on leaky water tank drain valves, and replacing them. If you have already done this, then feel free to move on, and good luck!
If you go to the Fresh Water Systems sub-forum where we are:
http://www.airforums.com/forums/f443/
. . . you can then hit "Search this Forum" for "drain valve" [toggle on "Show Posts"] and get these results:
http://www.airforums.com/forums/sear...archid=6805592
"water tank leak" yields:
http://www.airforums.com/forums/sear...archid=6805600
There may be an inspection plate patch in your bottom belly skin which will let you see more upon removal. A photo or two will make it easier for those more expert than me to give you better advice.
Good luck!
Peter
PS -- These threads may be helpful:
http://www.airforums.com/forums/f443...ks-111378.html
http://www.airforums.com/forums/f443...3d-160792.html
http://www.airforums.com/forums/f443...in-151072.html
ROBERT CROSS made up a great replacement valve for his drain, although his configuration may be different than yours. See Post #4 here:
http://www.airforums.com/forums/f443...nk-143559.html
Linear Mode
