Big trip tomorrow, Big Problem???

[ihsolutions]

First let me say that I rarely travel with much fresh water in my tank. But last trip out the state park has an awfully rusty fresh water fill so I brought about a half tank from home, maybe a little more.

Today while filling the fresh at home, water started spewing back out the full at probably only 1/4 tank. I removed the basement wall to see of the hole was sagging, and it was, but holding it to a nice slope did nothing to fix the problem.

So I started removing part of the giant corrugated underbelly to see where the problem was. See pics of what I found. Note, there are no leaks anywhere. But the bottom of the tank is badly convex, with the center low point probably 8" lower than the sides.

The metal supports all appear intact, and yet it is bowing this much. How is this possible? Something must be broken, right?

I've heard of tanks falling out on the road but never heard of anything like this. Any advice is much appreciated! We are supposed to be on the road early tomorrow for 2 weeks.

By the way, that corrugated thing is near impossible to remove. Too much stuff in the way like gas lines, sewer pipe, axle hangars, etc.

 

[porthole]

No pictures.

And that corrugated thing - remove the gas pipe. You should be able to wrestle it out then.
You may have to cut some slits in to clear the sewer pipe etc.
Patch it back up with Gorilla brand black duct tape.

As to the tank fill, trying blowing some air through the vent hoses.

 

[ihsolutions]

Sorry about that. HRV app for iPhone didn't let me add pictures. Did it from the home PC. The photos are difficult to illustrate the amount of sag. My question is, how is the sag possible if the rails and supports holding it are all steel?? Steel doesn't stretch.

 

[ihsolutions]

Another perhaps more important question I should ask first... is this the shape of the tank originally? If this is the intended design then perhaps there is no problem?

 

[osims]

Every so often I have to blow air thru my vent line to fill the tank. Vent line sags and fills with water and tank will not take water, been doing this since new.

 

[PhotoPete]

I too am thinking that it's not a sagging issue but a ventilation issue.

 

[ihsolutions]

OK, it was the vent.

This morning I was filling the fresh, and it overfilled and spit back out the fill opening. Later today when I tried to fill there must have been water in the vent line as a result.

Note to self: when blowing compressed air in the vent line, STAND BACK! Eventually the fill line will barf a 1" stream of solid water at about 100mph directly in your face. Thank goodness it's summer.

So this problem made me aware of the sagging issue. The tank appears not to be rectangular like I orginally thought, but more like a "T" shape (where the top, wider part of the T sits on frame rails. The bottom of the tank is supported by the straps.

It is sagging quite a bit. There is a LOT of volume below where the drain line exits the tank, and below the "E" sensor on the tank. This explains why when I get to "E", I have about enough water to wash hands and flush the toilet once before the pump runs dry.

At the end of the day, the question is, with this sagging going on, how much water is safe to carry while in transit? 1/3 tank maybe?

 

[rick_debbie_gallant]

Water = 8.33 lbs per gallon.
40 gallon tank x 8.33 = a bunch of weight sloshing around in the tank. Most likely there are zero baffles in there to stop it. Not sure how many gallons of water your tank holds. Myself, I try not to carry much water at all.

 

[jnbhobe]

I had mine sagging, the tank has a locating slot molded in the top of the tank and it fell far enough to let it bend. I emptied the tank and pushed it up in place, slid a piece of 1/8 in aluminum under the straps and closed it up. Then I took a piece of 1 1/2 X 3 in X 3/16 tubing 6ft long and bolted it to the bottom of the frame, works great I've done it to many other rigs. I run with a full tank of water most of the time.

 

[JohnDar]

I wouldn't drive around with a full 75 gallons (625 lbs.) in there, but when you fill it and use it, the sagging should decrease as the volume decreases. If you installed some sort of filtration system, you might be able to eliminate the well water taste.

 

[TravelTiger]

We rarely travel with water, however, have winter camped with full fresh tank. Ours looked like yours. We didn't do anything about the sagging, because I felt the steel crossbars would keep it in place. We added a heat pad between the existing crossbars so we couldn't really add additional.

 

[TeJay]

It may just be me but I don't believe that any sagging would or should be acceptable. Lets think about this. They don't make the holding tanks with sags built into them. If they sag then they are not properly supported. If they are not properly supported then they need to be fixed. If you have a tank that sags and that's how you leave it then I would think you are asking for problems. On our 24-RBS NT while getting ready for our first trip I looked under the unit and there was a 7 inch sag in the fresh water tank. I pulled down the coroplast and one of the straps was broken. The dealer fixed it and I asked that a piece of plywood be inserted under the straps against the bottom of the tank to spread the weight over the plywood so that it wouldn't sag. That's what I believe should have been done at the factory. Why would you produce a unit with 35 to 75 gallon capacity for fresh water then not support it in the event that the owner does fill it??? If you fill it and it sags then it was built poorly. That's just what they do and the sooner the owners take them to task for this type of construction the sooner they will do things as they should. We purchased a unit. It was rated at 7,000 capacity (unit and a full load). The axles were rated at 6,000 lbs. One thousand pounds under the units max rating. The dealer called the factory and they said no to upgraded axles. Two hours later I called the factory and within 3 days the new larger axles were delivered and installed. That happened because I the owner discovered what they the factory already knew. Smaller axles were installed to save $$$$.
TeJay

 

[jnbhobe]

I wouldn't drive around with a full 75 gallons (625 lbs.) in there, but when you fill it and use it, the sagging should decrease as the volume decreases. If you installed some sort of filtration system, you might be able to eliminate the well water taste.

Where I go John you just don't get water that easy. Closest water I would trust is 35 miles from camp so I might as well be full for the 75 mile trip.

 

[bighorn3370]

I have have filled my tank full and driven with it full. I never have had a tank fall out. I have not looked at my BH to see how much sagging there is. On my SOB, the bottom was not covered, and the tank sagged in the middle. I could push it up and drain the water. I think the biggest problem is the plastic tank. The gray and black tanks are made of a harder plastic. When the tanks used to be above the floor of the RV, they did not sag. Now they sag, due to lack of support. Ernie

 

[Bksvo]

I'd be curious what the tank and straps look like when the tank is empty. When I installed a tank flush in the rear black tank on my Cyclone, I was surprised to see the straps for the black and gray tanks were installed with quite a bit of sag. They do absolutely nothing, as far as I can tell, unless the tanks should slip off the rails they are installed on. I do wonder if the tanks sag when they are full, and then they touch the straps. I thought this was pretty strange, but the three tanks I could see from where I was working were all the same.

 

[porthole]

I'd be curious what the tank and straps look like when the tank is empty. When I installed a tank flush in the rear black tank on my Cyclone, I was surprised to see the straps for the black and gray tanks were installed with quite a bit of sag. They do absolutely nothing, as far as I can tell, unless the tanks should slip off the rails they are installed on. I do wonder if the tanks sag when they are full, and then they touch the straps. I thought this was pretty strange, but the three tanks I could see from where I was working were all the same.

Those straps will be supporting the tank when it fills up. If the tank didn't give a little I would think they would stand a better chance of rupturing when traveling with our "rolling earthquakes"

 

[Bob&Patty]

IMHO, they all sag somewhat. The straps are made to be loose under the tanks and support the tanks when full. Have had our coach for 5 years now and not a problem with the tanks when full.

 

[hoefler]

The sag in my mind is NOT acceptable!! You will loose the tank if you continue to travel with water on board. The strap idea used on these units is p**s poor at best. There should be a piece of sheet good under the tank to spread out the load, minimum. My tank almost fell out from the strap failing, allowing the 3/4" OSB to sag out of the front and back rails. The sag will be permanent if it remains unsupported, you will loose the use of the water in the sag. I repaired mine by replacing the OSB with Advantech floor decking and installing 3 pieces of angle iron between the front and back rails. I travel with a full load of water, 100 gallons with out any issues or worries now.