Black Tank Construction

[Dee_Dub]

Well I did the unforgiveable two days ago! We lost water in the State Park that we are staying in and I wanted to flush out the system before re-connecting the lines. WELL - In my haste I left the flush line running and the valves were closed. My neighbors reported hearing a loud pop. Needless to say we had a sewage problem like no other. After dropping the belly and cleaning everything with a power washer I put more water into the black tank to see where there might have been some damage to tank or lines. I was unable to identify any leaks! My question is how did so much sewage enter into the belly area and there NOT be an obvious leak.

Is there a pressure relief valve built into the black tank?

[jeffba]

it may be on the top of the tank. Tanks used to be made as 2 pieces and they glued on a top to teh tank

[jimcol]

Many on this forum have reported them to leak where the pipe into the tank is not properly sealed/glued. You will only observe that when you overfill the tank. That's when I observed mine leaking. I had got distracted while back flushing the tank. Did nothing as it would be difficult to get to and repair. Just quit overfilling the tank.

[Montana Man]

That's my bet, a two piece tank. Keystone installs these tanks not in accordance to the manufacturers recommendation. Search the forum and you'll find plenty on this subject.

[dfb]

The tank must be removed.. ours split where they glues the top to it..its on top..

[dfb]

Should make keystone pay for new ones.. im fed up with the problems..

[kowbra]

Originally Posted by Montana Man

That's my bet, a two piece tank. Keystone installs these tanks not in accordance to the manufacturers recommendation. Search the forum and you'll find plenty on this subject.

I don't know about prior years, but the 2021 models use a 1 piece rotocast tank...
https://www.keystonerv.com/innovatio...-wheel-chassis

And, as to manufacturer recommendations, do you have info on where Keystone is not installing properly?

Thanks,
Brad

[ForBruce]

Originally Posted by Dee_Dub

Well I did the unforgiveable two days ago! We lost water in the State Park that we are staying in and I wanted to flush out the system before re-connecting the lines. WELL - In my haste I left the flush line running and the valves were closed. My neighbors reported hearing a loud pop. Needless to say we had a sewage problem like no other. After dropping the belly and cleaning everything with a power washer I put more water into the black tank to see where there might have been some damage to tank or lines. I was unable to identify any leaks! My question is how did so much sewage enter into the belly area and there NOT be an obvious leak.

Is there a pressure relief valve built into the black tank?

seems to me the "BLACK STUFF" should have cascaded out of your roof vent and all over the roof....the loud pop might have been caused by pressure build up due to a clogged roof vent .(either at the roof or at the tank )

sounds like you blew off one of the rubber tank fittings and deposited all over the floor and under....

imho---- i would do a visual and not let this just go unattended.....

even if it cost you some bucks.....better than being a slave to the tank.. not knowing when the next **********

[Montana Man]

Originally Posted by kowbra

I don't know about prior years, but the 2021 models use a 1 piece rotocast tank...
https://www.keystonerv.com/innovatio...-wheel-chassis

And, as to manufacturer recommendations, do you have info on where Keystone is not installing properly?

Thanks,
Brad

Mine is a 2016 made in 2015 and it also has rotocast tanks. I don't know if the legacy package has anything to do with the better tanks or not.

My buddy's unit blew 3 of the two piece tanks before we learned what the problem was. I was fortunate enough to speak with someone at the manufacturer that makes those tanks and they said the tanks are not designed to be hung from the flange without support underneath the tank. He actually said they are being installed not according to their recommendations.

[jcurtis934]

If you have the black bas two piece tank, it will more than likely have blown open a foot or so of the flange seal. You have to cut pipes and remove one side support tube to drop the tank and remove it. The tank needs to be totally dry inside to be able to repair it with a product like plasti-mend. Been there, done that with black tank and galley tank. And they do make a loud noise when the seam let's go. I don't know if montana ever supported the tanks under the bottom OR if they just finally switched to a one piece tank.

[beeje]

I have said it many times on many treads, these 2 piece tank can not handle being over filled or being transported with waste in them. You really have to pay more attention to what is in your tanks and when to dump them.

[dfb]

Here is the tank out...]
[/ATTACH]

[dfb]

Are where i cut the pipes... used rubber boots to reattach..

[dfb]

Originally Posted by Montana Man

Mine is a 2016 made in 2015 and it also has rotocast tanks. I don't know if the legacy package has anything to do with the better tanks or not.

My buddy's unit blew 3 of the two piece tanks before we learned what the problem was. I was fortunate enough to speak with someone at the manufacturer that makes those tanks and they said the tanks are not designed to be hung from the flange without support underneath the tank. He actually said they are being installed not according to their recommendations.

LEGACY MEANS YOU GET A REAR CAP, HIGH GLOSS GELCOAT FOR ANOTHER 6000! I do notice when selling the legacy nada or the dealers dont add even tho we paid for it!.. we get no better materials or construction and we get no add when trading or selling..

[beeje]

Originally Posted by dfb

LEGACY MEANS YOU GET A REAR CAP, HIGH GLOSS GELCOAT FOR ANOTHER 6000! I do notice when selling the legacy nada or the dealers dont add even tho we paid for it!.. we get no better materials or construction and we get no add when trading or selling..

The Legacy Edition is just another money grab for Keystone to suck money out of your pocket. Our 2011 unit has a rear cap and high gloss gelcoat. We bought it used and it didn't cost me a nickel more for those two things.

[Montana Man]

There is no overfilling the tanks. There is either full or less than full. Full doesn't mean overloaded unless the tank is mounted improperly thereby reducing it's weight bearing capacity.

The legacy package is more than a rear cap and high gloss exterior. It isn't for everyone but what it did offer we liked.

[Rondo]

Mike-- You are wrong about not overfilling the tanks. You can and yours if different entirely from the Dee Dub. Your tanks are one piece molded tanks where his are two piece tanks with a plastic weld and glue attaching the top to the bottom of the tank. The weld/glue is not strong enough to hold when to much pressure is applied inside the tank from overfilling it without the valve being open to let it drain. dfb's pictures show the tank that Dee Dub has and yours is one complete piece not two.

beeje-- the difference between the Legacy and the Montana is the front and rear cap, disc brakes, and the command center to start with. The Legacy is the new name for the Big Sky which was put out of commission several years ago. The new Montana's are the regular Montana from years back but without the back cap. The Montana High Country is now what used to be the Mountaineer.

[kowbra]

Originally Posted by Rondo

Mike-- You are wrong about not overfilling the tanks. You can and yours if different entirely from the Dee Dub. Your tanks are one piece molded tanks where his are two piece tanks with a plastic weld and glue attaching the top to the bottom of the tank. The weld/glue is not strong enough to hold when to much pressure is applied inside the tank from overfilling it without the valve being open to let it drain. dfb's pictures show the tank that Dee Dub has and yours is one complete piece not two.

beeje-- the difference between the Legacy and the Montana is the front and rear cap, disc brakes, and the command center to start with. The Legacy is the new name for the Big Sky which was put out of commission several years ago. The new Montana's are the regular Montana from years back but without the back cap. The Montana High Country is now what used to be the Mountaineer.

Rondo, thanks for setting the record straight.

And, to add to your list on the Legacy package, it also adds Furrion rear and side cameras, electric cord reel, surge protector and generator prep... and there is no way we paid $6000 for it, in fact it was thrown in almost for no charge. It was a fantastic deal just for the disc brakes alone.

I'm amazed at how much misinformation is casually thrown out. It's not hard to check; just go to the Montana site and spend a few minutes... https://www.keystonerv.com/product/m...y-fifth-wheels

BTW, the information is there also that the tanks are 1 piece rotocast.

And, as to an opinion... I agree with the statement "they don't make them like they used to"... except that in many ways they are not as good, while in other ways they are far better...

Brad

[Montana Man]

I do not understand the concept of over filling the tank. Tanks hold X amount of fluid. They have a capacity according to their size and are advertised as such. Nowhere does it say only fill to X percent of capacity. Therefore a 50 gallon tank should hold 50 gallons, etc.

Now, if the tank isn't mounted properly, then that changes everything. Keystone didn't mount the two piece tanks properly nor do they say do not utilize it's full capacity.

[beeje]

Originally Posted by Montana Man

I do not understand the concept of over filling the tank. Tanks hold X amount of fluid. They have a capacity according to their size and are advertised as such. Nowhere does it say only fill to X percent of capacity. Therefore a 50 gallon tank should hold 50 gallons, etc.

Now, if the tank isn't mounted properly, then that changes everything. Keystone didn't mount the two piece tanks properly nor do they say do not utilize it's full capacity.

It would be true about not causing any pressure on a Ridgid type of tank like steel or aluminum or something like that. But these tanks are plastic and expand and contract quite a bit. So when they are overfilled it literally pushes the top lid off of the tank