Here's a tip: Don't over fill your fresh water tank.

[CedarCreekWoody]

Originally Posted by Skyliner

This is a common issue with most campers and not really caused by overloading tanks. I had a tank that was only 1/2 full fall off on me.

The solution is to reinforce the brackets with perpendicular brackets that keep everything in place and prevent the tanks from falling thru.

Every camper I've purchased since my tank fell off has had the tanks brackets modified. Its no big deal, better to fix it before it falls out, much easier.

Do you have photos or details of your reinforcement?

[Mr Havercamp]

Originally Posted by rockfordroo

Mr Havercamp had the same problem. Here's the thread:

http://www.forestriverforums.com/for...ut-108183.html

I don't know why his pics are missing, though. If you PM him, he can probably email you his pics and his fix.

The pics are missing because I deleted my photobucket account. I will send them when I find which one of my drives I dumped them on. The fix was heavier angles. The supports are under engineered by the manufacturer, Lippert Components (LCI). For laughs call them and report the problem. The him hawing and red tape run around they perform is amazing. One of the main criteria for our next trailer will be which brand/model has the least LCI stuff on it.

Rockwood uses the cheapest fresh water tank they can find. Then they jam it tight to the floor. You do not think the top will balloon up when filled??? Think again. Have the camper an inch or two out of level side to side and see what happens. The floor is oly attached to the frame at the perimeter where its bolted to the outriggers. The tank is essentially a jack and will arch the floor up if you fill it full when out of level.

In contrast the second tank I added which was made by Aplha is much thicker plastic with rounded corners and does not balloon anywhere near as much as the thin cheap tank Rockwood used. I also installed both tanks with a 3/4" gap to the underside of the floor.

[Ca Cardinal]

Some of you may find that when FR went to the wider body trailers they did not have the company who supplies the frames put in heavier angle iron that the front of the water tank sits on. They did put in heavier angle iron in the rear that they install and because of the extra width the front angle iron was not able to handle the additional flexing that the full water tank put on it. It caused deflection on the front angle iron and caused the tanks to drop out.

So check your units to see if you have different (Gauge )thickness on the font angle than in the back. If so then this is a design flaw that FR is aware of as it has been brought to their attention and maybe you can get them to pay for your repairs.

[isp435]

While filling my tank for hunting camp, the fill hose came off the nipple on the tank. Water everywhere. Had to remove the front support bracket which is attached by self taping screws to lower the tank to gain access to the fill tube and attempt to reattach it. The support brackets are not strong enough and the tank can move side to side which was the main reason the hose came off in the first place. Another project to do next spring.

[Nancyc7]

I find it astonishing you could make this tank balloon up and fall off! What kind of plastic is this made of? How could it handle the heat of traveling down the highway?

If I had read this forum prior to buying a motorhome, I would not have the courage.
Ignorance may not be blissful either.....

[Hclarkx]

Originally Posted by Tireman9

Not sure how you "overfill" a closed tank. Water weighs about 8# a gal and the tank capacity is fixed. The RV company knows the static weight and should of course account for bouncing which could double the weight. So full is full.
Water pressure doesn't enter into the question as there is nothing for the water in the tank to press against other than maybe 50 psi for the area covered by the fill pipe diameter.

Any competent engineer can establish a minimum metal thickness to support the water tank.

. .. . . . . . .

As posted, the tank is plastic and can expand. It takes only a few psi to do this. Mostly the large flat top and bottom sides expand outward.

Your assumption about competent engineers is optimistic. I have a Rockwood Ultralight and there is a lot of terrible engineering in it and that is compounded by poor assembly and a total lack of quality control (I'm an engineer with 50 years of experience so am qualified to judge). I've had over 25 significant issues that have required about that many days to rectify. I come back from each outing with a new list of things that need fixing, most that should have never happened or should have been fixed via quality control.

[Hclarkx]

Originally Posted by Nancyc7

I find it astonishing you could make this tank balloon up and fall off! What kind of plastic is this made of? How could it handle the heat of traveling down the highway?

The large flat top and bottom do the bulging. Blow into an empty gallon milk container and with just a few psi the flat sides bulge outward. With enough pressure it will turn into a balloon shape because that shape has the greatest volume. The tanks on some of our RV's don't have walls much thicker than that milk jug (yes, thicker, but not enough to prevent bulging of the flat sides).

[Dave Lyon]

It seems odd - it appears that the tank is pressurized?

I fill my FW tank until water runs out of the vent hose and never had a problem....maybe I'm just lucky and on borrowed time.

[KyDan]

Originally Posted by Dave Lyon

It seems odd - it appears that the tank is pressurized?

I fill my FW tank until water runs out of the vent hose and never had a problem....maybe I'm just lucky and on borrowed time.

Possibly! It's possible to shove a cut off hose deep into the gravity fill and
turn the faucet on full blast and when the tank is full the water would not
be able to get out the overflow fast enough. City water pressure on a full
tank will definitely bulge the sides! The bulging sides pressing up against the
floor can easily bend the supports and drop the tank.

Pulling off the belly cover and inspecting my water tank supports is on my short list but
I haven't done it yet....

[Hclarkx]

Originally Posted by Dave Lyon

It seems odd - it appears that the tank is pressurized?

I fill my FW tank until water runs out of the vent hose and never had a problem....maybe I'm just lucky and on borrowed time.

I do likewise, but from what I'm reading here, the fresh water (and probably the other tanks) may have very little margin in their supporting brackets.

Sometimes we have to drive some distance with a full tank (from fill station to the site or from the site to a dump station) and I have to wonder if a large pot hole or speed bump might drop a tank through its supports.

I too am going to have a closer took even though it means taking out hundreds of screws to drop the bottom cover.

[rockfordroo]

Originally Posted by Dave Lyon

It seems odd - it appears that the tank is pressurized?

I fill my FW tank until water runs out of the vent hose and never had a problem....maybe I'm just lucky and on borrowed time.

If you figure you have a tank that is 2' x 4', that's 1152 sq inches. Therefore, every 1 psi you pressurize the tank, you're putting 1152 pounds of pressure on the top of the tank (that's a bit more than 1/2 a ton!). 15 psi is equal to 33 ft of water, therefore, if you have to push water up 1 foot to the top of your vent, that's about 1/2 psi; so you'll put about 626 pounds of force on the top of your tank just to push the water out of the vent. If the vent can't vent the same flow of water you're putting in the tank, the pressure in the tank will go up and so will the amount of force on the top of the tank.

Hopefully this shows you how easy it is to apply a very large force to the top of the tank. (This force will also be applied to the bottom of the tank PLUS the weight of the water. A smaller force will be applied to the sides, since their square inch area is less than the top and bottom.)

[Hclarkx]

Rockfordroo ....... very well done post.

[Mark72358]

Originally Posted by Tireman9

I'm not sure if they actually have any BS Mechanical Engineers working on the structural integrity of the support structure.

I think the problem is that they employ BS Mechanical Engineers. They could do much better by employing someone with some common sense and math skills.
IMHO most Engineers these days are a joke, mommy / daddy four year paid party plan.
There are a few good engineer's out there but very few and I don't think RV manufactures are willing to spend the money to employ them.
It's all about dollars vs sense.

[babock]

Originally Posted by Mark72358

I think the problem is that they employ BS Mechanical Engineers. They could do much better by employing someone with some common sense and math skills.
IMHO most Engineers these days are a joke, mommy / daddy four year paid party plan.
There are a few good engineer's out there but very few and I don't think RV manufactures are willing to spend the money to employ them.
It's all about dollars vs sense.

LOL...posting on a 3 year old thread? Complaining about common sense?

[aeblank]

Originally Posted by babock

LOL...posting on a 3 year old thread? Complaining about common sense?

Only an engineer would notice such a detail. Er, wait, that's not common sense.

My favorite is mechanics saying engineers need to be a mechanic for a year, first. As if we (I'z an engineer) sit around trying to make life difficult for them and repairs are the *only* consideration.

[babock]

Originally Posted by aeblank

Only an engineer would notice such a detail. Er, wait, that's not common sense.

My favorite is mechanics saying engineers need to be a mechanic for a year, first. As if we (I'z an engineer) sit around trying to make life difficult for them and repairs are the *only* consideration.

Actually, it is common sense to look at the dates of the posts before you to see if you are reviving an old thread. Of course...it's not very common.

[aeblank]

Originally Posted by babock

Actually, it is common sense to look at the dates of the posts before you to see if you are reviving an old thread. Of course...it's not very common.

I was just being a smart a.....er, smartie pants.

[babock]

Originally Posted by aeblank

I was just being a smart a.....er, smartie pants.

So was I!

[Hclarkx]

Originally Posted by aeblank

Only an engineer would notice such a detail. Er, wait, that's not common sense.

My favorite is mechanics saying engineers need to be a mechanic for a year, first. As if we (I'z an engineer) sit around trying to make life difficult for them and repairs are the *only* consideration.

There is something to say for having practical experience before becoming an engineer though. I was an electrician for six years before getting my EE degree and that helped me immensely over the years.

As an aside, I've worked with lawyers three different times that had an EE or ME degree before going on to law school. Working with them was great.

Where I went to school, there were a considerable number of foreign students as well. Most could not use a hammer or screwdriver or pair of pliers. Because I could work with my hands, I was their go to person for help in shop classes (I wonder if colleges still have shop classes?).

But, yes, engineers do take maintainability into account .... usually.

[JoeCampsNE]

Yep. had the same issue on my FL ML 21 FBRS. Front bent support under fresh water tank. I used a hydraulic jack to straighten the support and then used four heavy duty tie downs and ratched them under the tank from the frame.

I also use a hose end volume meter when I fill the tank and stop a few gallons short of capacity. Been great since.