Water tank project

I just finished my water tank project and it turned out pretty good. Rather than clog up the forum with a bunch of photos, follow the link in my signature to see photos.

My original water tank had to be replaced because it had a hole in it. The hole was caused by poor mounting technique. The original tank was held in place by angle iron supports under a flange that ran along the top of the tank. Additionally, sheet metal straps were run under the tank. When the tank was full, it bulged into the sheet metal straps and eventually wore a hole in it. Anyone that has this setup needs to take a close look at it. At the very least, I would recommend placing a piece of plywood between the straps and the tank to provide a support for the bottom of the tank. Others have had problems with improperlly installed screws getting into the tank; an inspection would be a smart thing to do.

Forest River (Rod) was kind enough to send me a replacement tank free of charge. After thinking about this for a while, I decided this was the perfect opportunity to increase my fresh water supply; something I have had on my list for some time. The original tank was 40 gallons; the replacement is 50 gallons and I installed a second one that I purchased from FR; I now have a capacity of 100 gallons. I also have a 65 gallong tank that fits in the bed of my pickup for extended camping trips. Realize this is a lot of weight; 800 pounds in the cat, another 520 pound in the truck if I choose to take that tank. In most cases, these tanks will not be filled until very close to destination.

The entire mounting system had to be changed. For two reasons; first the replacement tanks are different, they do not have the flange around the top side that was used to mount the tank at the factory. Second; this whole problem was caused by poor mounting, so something different was called for. I used 1 1/2" angle iron to fabricate supports for the long sides of each tank (the back of the rear tank uses the factory frame rail). I put plywood between these angle irons to support the bottom of the tanks. See photos.

Plumbing: The new tanks came with an extra bottom fitting. This worked out great. I plumbed the rear tank just like the original tank; fill, vent, & feed to the water pump. I ran a tee off the fill line to the front tank and also a tee off the vent line to the front tank. Next, I tied both tanks together using the extra bottom fitting; used 3/4" scd 40 PVC. This will keep the water level the same in both tanks; necessary since only the rear tank has a feed to the water pump. Originally I did not tee the fill line, figuring that the PVC line would allow the front tank to fill evenly with the rear tank. This did not work; I realized that the fill line (1 1/4") is also the main vent when filling the tank. The small vent is just for drawing water off the tanks and is not adequate for venting during the fill process; anyway, without the fill line tee, the front tank took a loooong time to fill. I considered installing another fill port so that each tank has its own; still an option if I don't like the way this set up works.

Since the water level should be the same in both tanks, I just used the existing level gauge wiring and connected it to the rear tank.

Sorry to be so long winded; hope this makes sense.

Makes sense. Good photos. Thanks.

Nice work.

I still have the sagging "T" type tanks, but so far, no leaks.

I had to tee the fill tubing as well when I added my second tank. It was a slow process to equalize otherwise. I still have the small tank drain valve. It takes a loonnnngg time to empty the tanks.

My only complaint is the bottom 1" or so of tank is not accessible. It's too bad they can put the bungs lower. I can't seem to get the last 10 or so gallons.

I also just finished modifications to my fresh water tank. I had the problem of it not filling all the way to the top or being able to use all the water at the bottom due to where the vent and suction bungs were located. I removed the tank and had my local RV shop install a new vent bung on the top and a new pump suction/drain bung on the bottom corner. Now I can fill all the way to the top and just about get it all out before sucking air and loosing prime on the pump. Big deal for us since we always dry camp.

Nice job

I exposed my fresh water tank to fix the venting when my TT was still very new. It looked to me like the tank was built with the bulging bottom to start with but mine has no braces accross the bottom. I'm not real happy with the way it hangs from metal rail either. I was able to move the empty tank back and forth about an inch so I'm sure it slides while driving and that can't be good.
Very nice mod you did, I sure hope we don't have to do it to the black tank some day!

The bottom of the tank is not supposed to bulge; probably won't hurt anything since you don't have metal straps to rub a hole in it (there will be a lot of water down there that you can't use). I doubt the metal straps did anything to actually support the tank. The top flange support is not ideal, but probably ok.

Scott,

How did you detach the belly panel (picture 8 of 14 in your gallery)? I see on mine how they are bolted to the side rails, but at the end (rear bumper side) mine are wrapped around the end of the frame and clamped between the body of the trailer and the frame. Did you cut yours, or did you figure out how to get it out?

I hope I'm describing this correctly.

mattebury wrote:Scott,

How did you detach the belly panel (picture 8 of 14 in your gallery)? I see on mine how they are bolted to the side rails, but at the end (rear bumper side) mine are wrapped around the end of the frame and clamped between the body of the trailer and the frame. Did you cut yours, or did you figure out how to get it out?

I hope I'm describing this correctly.

Yes, you described it exactly. I think they put it on before they installed the floor of the trailer. The only way to take it off without cutting it, is to start from the front of the cat and take the whole thing off; not fun.

I cut it just to after it crosses under the rear frame member and starts to go up. In hind sight, I wish I would have cut it as high as possible so I would have had more material to work with. I re-installed it using a light piece of angle iron (actually one of the old water tank supports). I screwed the belly panel to the angle iron (screws facing down, because my water tank is now resting on this rear member) and then put two bolts through the rear member to attach the angle iron. In the future I will only have to remove two nuts and this angle iron will come down along with the entire rear edge of the belly panel.

I added two more photos to show how I did this. You can see the screws sticking down; these are holding the belly pan to the angle iron and should never have to come out. There is a bolt on each end (facing down, away from the water tank) that holds the angle iron.

Sweet mod Scott! I've been thinking about adding a second tank but not tied to the OEM tank. I still need to support my OEM tank yet as it's sagging badly. I also needed to know how you got your belly liner down @ the rear of the trailer. Thanks!

Earl

Looking at the pics, it looks like Scott just left the rear portion attached and pulled it out of the way.

ScottandGrace wrote:Looking at the pics, it looks like Scott just left the rear portion attached and pulled it out of the way.

I cut it where it goes over the top of the rear frame member.

When I did mine, it wasn't tucked at the rear by the bumper, it was just held in by a lot of screws w/ washers. I just rolled it toward the axles.

Great job. I have to replace my tank also. The idea of adding a second tank, I really like. Did you think about using flex instead of solid PVC?

I'm pretty sure the angle iron is 1/8" thickness. You will notice I used a cross brace on the front tanks. Initially I did not have it and the weight of a full tank would spread the two angle irons apart. Not a problem with the rear tank, where one side is the trailer frame; can't spread.

The Plywood is 1/2".

So far I have been happy with this mod, but a couple of notes. Both tanks fill through the same port. I have to fill slower than before to make sure both tanks get full. 100 gallons of water weighs a lot! I can definitely feel the tail trying to wag the dog with all that weight back there; A position further forward would help, but not sure it is possible. I have just decided not to fill for longer trips.

PS: At first I figured I did not have to tie the front tank into the filler tube. I thought with the PVC pipes tying the two tanks together, the front tank would fill that way. What I did not realize is that the fill tube is a major part of the vent system when filling the tanks; the small vent hose is not enough. With the fill tube only going to one tank; it took forever to fill. I added a tee and fill tubing to the new tank.

PSS: with 100 gallons, my wife and I have gone four days and still had to drain the fresh water tank before heading home.

I think when I replace my tank this summer I am also going to install a See Level tank gauge system. I am tired of showing full after I empty my tanks.

Here is a link to a Seelevel installation:
http://www.5thwheelforums.com/seelevel.pdf

Update: We (2 of us) just went on a 6+ day trip with out running out of water. We were careful and took Navy showers everyday. This was a great mod (mandatory for me because of the problems with original tank). Just be mindful of the weight; I don't fill until I'm close to my destination.

shooter wrote:Here is a link to a Seelevel installation:
http://www.5thwheelforums.com/seelevel.pdf

Interesting how you can tie all the sensor wires together and the reader can separate them into individual readings.

Looking for the cost.

Portagie1968 wrote:

shooter wrote:Here is a link to a Seelevel installation:
http://www.5thwheelforums.com/seelevel.pdf

Interesting how you can tie all the sensor wires together and the reader can separate them into individual readings.

Looking for the cost.

http://www.bestconverter.com/709-4P-SeeLevel-II-Tank-Monitor-System_p_184.html

They are really proud of their product I can see. Thank you for the web site.

You're welcome.