2008 Forest River Sandstorm - developed a leak at the base of the forward fresh water tank; where the drain ties in (see photo - hopefully it works). I can see what appears to be a threaded ring that is cracked and this is where the water drips. I was unsure of how the assembly threads together, so I tried silicone as a quick-fix. That worked temporarily but the leak persists; albeit very slow. I am planning a permanent fix (cutting the PVC and re-plumbing) but I am hoping someone can tell me how these pieces thread together and/or give me some advice before I start cutting pipe. Thanks in advance!

Here is a wider angle photo of the entire assembly.

I'm pretty sure the lower nuts just unscrew to allow the drain pipe to be removed then the upper nut unscrews BUT I'm not sure how the pipes connect to the tank bottom. Hopefully, the bottom could have a discharge pipe permanently attached to the tank.I've had success plugging holes with JB Welds `Water Weld' which is an epoxy putty that is molded around the leak area and allowed to harden. Or Duluth Trading has an Extreme Tape sticks to itself and can be wrapped around to seal the leak.

Thanks Dick. I ordered the Duluth Trading extreme tape. Good stuff to have around anyway. Did some poking around today and pried back the broken collar a little bit. It is female threaded and plastic welded to the bottom of the tank. No easy way to replace it. I'm going with the Extreme tape as a hopefully more permanent fix....

ThomasFour wrote:Thanks Dick. I ordered the Duluth Trading extreme tape. Good stuff to have around anyway. Did some poking around today and pried back the broken collar a little bit. It is female threaded and plastic welded to the bottom of the tank. No easy way to replace it. I'm going with the Extreme tape as a hopefully more permanent fix....yes the threaded piece is thermal welded to the tank then a slip/thread adapter is screwed into the first piece and everything else is PVC glued. In order to remove the slip/thread adapter you need to cut the pipe and unscrew it, then you can use a coupling and reglue or just replace it all, PVC is cheap and easy to work with. The drain valves are flanged so can be reused. If the fitting at the tank is the one leaking it was probably over tightened and cracked, not much you can do for that, special machine is needed to weld to the plastic.

Never seen a fresh water tank with a valve like that.

Fresh Water Drain - repair help needed | Good Sam Community

ThomasFour
Explorer
Mar 19, 2016
mapguy wrote:
Try the link below for tools and supplies.

Spinwelding Tools/supplies

Thanks!
mapguy
Explorer
Mar 18, 2016
Try the link below for tools and supplies.

Spinwelding Tools/supplies
ThomasFour
Explorer
Mar 17, 2016
ThomasFour
Explorer
Mar 17, 2016
ThomasFour wrote:
BigBlockTank wrote:
I'm a previous RV tech, and have done this a few times. Find and buy the fitting for the tank. Then find what you need to adapt it to a drill. Either an electric or cordless will work. As previously stated, it doesn't take much to get it to melt. Then you have to hold it VERY still until it cools, about 20 seconds or so.

Unfortunately, to do it right, and to do it easily, you might have to pull the fresh tank out. At least, I would, I'm pretty sure. If there is 24-30" of clearance, you may be able to do it without pulling it. (the clearance depends on your drill, all the adaptors, and the repair piece)

Thanks. Being a do-it-yourselfer, I may try it then....

So here is where I am at on this project. The threaded adapter (white piece) is definitely melted into the black tank; as I am sure it was supposed to be. I have used my Dremel to grind it to its current state. Chipping at it with a chisel was less productive. So, for those who had done this before....any advice going forward?
ThomasFour
Explorer
Mar 16, 2016
BigBlockTank wrote:
I'm a previous RV tech, and have done this a few times. Find and buy the fitting for the tank. Then find what you need to adapt it to a drill. Either an electric or cordless will work. As previously stated, it doesn't take much to get it to melt. Then you have to hold it VERY still until it cools, about 20 seconds or so.

Unfortunately, to do it right, and to do it easily, you might have to pull the fresh tank out. At least, I would, I'm pretty sure. If there is 24-30" of clearance, you may be able to do it without pulling it. (the clearance depends on your drill, all the adaptors, and the repair piece)

Thanks. Being a do-it-yourselfer, I may try it then....
BigBlockTank
Explorer
Mar 14, 2016
I'm a previous RV tech, and have done this a few times. Find and buy the fitting for the tank. Then find what you need to adapt it to a drill. Either an electric or cordless will work. As previously stated, it doesn't take much to get it to melt. Then you have to hold it VERY still until it cools, about 20 seconds or so.

Unfortunately, to do it right, and to do it easily, you might have to pull the fresh tank out. At least, I would, I'm pretty sure. If there is 24-30" of clearance, you may be able to do it without pulling it. (the clearance depends on your drill, all the adaptors, and the repair piece)
ThomasFour
Explorer
Mar 13, 2016
Thanks for the info. Do you mind if I ask how much it cost you in the end? I'm likely going to have to go the same route.
Strabo
Explorer
Mar 13, 2016
Just had ours repaired for the same reason, I didn't mess with it, had it repaired by professional RV shop. Tank had to be removed to be fixed in a proper way, all drain hardware was replaced also, from both tank connections. Our rig is a Forest River Sandpiper Sport fifthwheel toyhauler 2004. My RV tech says this kind of leak happens from towing off-road, makes sense to me.
ThomasFour
Explorer
Mar 13, 2016
I guess this is what you are referring to "allcool"

http://www.vintagetrailersupply.com/Spin-Weld-Fittings-p/vts-344.htm
ThomasFour
Explorer
Mar 13, 2016
Just to keep everyone updated, the Extreme Tape fix did NOT work. Tank is still leaking from the area where the flange meets the bottom of the tank. I used about 6 feet of tape and wrapped it copiously. There is no way to get the tape to seal this leak because of the awkward location right at the base of the tank. I believe the only way to fix it is as "allcool" described....

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