Sagging grey tank---normal??

aatauses

Well-known member
Hi everyone,
We have a bh3670 (2010) and the grey tank (#1, bathroom??) has a major sag in it. I took off the underbelly and all the braces seemed to be intack, but the tank itself has a sag in the bottom. It actually sags below the frame. Was this tank supposed to be flat on the bottom and level within the frame??
Do you think I need to get a new tank??
al
 

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slaytop

Well-known member
aatauses,
Check out the thread I started recently at . I show a method of supporting the gray and black tanks.
 

ChopperBill

Well-known member
Did I read someplace that this was finally corrected in the 2011 BH?

I don't know about the grey and black tanks because I haven't filled them up yet, but I have filled the fresh water tank. It didn't pop or creak or sagged down a bit. And it filled with no problem. Knocking on wood!
 

Wharton

Well-known member
I think the problem would occur as we bounce down the road so you had better keep checking along the way...................
 

ChopperBill

Well-known member
Our old 3055 fresh tank popped out of its mounts onto the "safety straps" the first time I filled it. This new one stayed on the mounts and you cant even tell it bulged at all. I consider it a major improvement. But, like I said I am Knocking on wood. I gave up hauling with a full tank of water. Too many mountains to climb around here. I carry a 50 gal. portable tank as I can find water most placed I go if I don't have hook ups.
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aatauses

Well-known member
Slaytop,
Thanks for the information----was your tank flat before you started your improvement? The grey tank I am talking about has a sag and it will not come out or reform back to flat. I have pushed up on it and it lifts the complete tank, not just in the sag area---otherwise I cannot get a flat bottom. I am not sure how I would try to put something flat on the bottom as it would only hit in the center because of the sagging. Let me know if your tank was originally flat on the bottom, before renovations. If it was not flat how did you get the sag out?
thanks
al
 

slaytop

Well-known member
aatauses
Sorry for the late reply. I didn't notice your question until now.
My tanks were sagging before I added the support. The bottoms have a compound angle to let the contents flow toward the drain. The support used needs to conform to the shape of the bottom. I pulled up my support so it followed the bottom edges. Some tanks have "Z" and others "L" shaped braces holding them up. I drilled holes through the "Z" braces for a threaded rod and made hangers to hook over the "L" braces and then down through the bottom support. The new support will have a tendency to lift the entire tank as you install it if it is completely empty. You can place your hand over the top edge of the tank to pull it down if it starts to lift when adding the support so you know how tight to make it. It will settle in later when the liquids are added. I hope this helps.
 

slaytop

Well-known member
Considering the design of the tanks it certainly is normal for the unsupported bottoms to sag. HL and owners confirm this because it seems like there are many tanks in these units that sag. I would think that the specs should also place the drain at the lowest point of the tank. If the lowest point of the sag remained above the drain then there would be no problem, however, that doesn't seem to be the case. The low point of these "normal" tanks appears to be the sagging bottom, not the corner where the drain is located. My work of supporting the tanks is primarily to keep the existing drain at the lowest point so they empty completely. That is "normal" in my definition of the word.
 

caissiel

Senior Member
When I look at the 3rd pic I can see that the angle is starting to bend. On mine it was down at least one inch. So I thighten the 2 loose strapes and added a connector to the beam on the left. My plan is to add a new angle that will be much stronger. This tank supports the Black tank that is on top and this tank can cause a lot of weight on the gray bottom tank
 

PUG

Pug
all of mine looked the same. I welded (could bolt) some steel braces under the tanks with plywood between braces and tank.
 
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