RV Toilet Flange to Black Tank connection

[JBarca]

Hi Folks,

Need some help. I have never had one of these apart and looking for info on how to pull the toilet flange from the black tank. It looks like the flange is ABS welded to a spout pipe that goes into the tank. There does not appear to have any welded fitting on the bottom of the pipe as seen from the inside of the pipe.

Does the tank have a rubber grommet connection that the pipe just sticks into the tank through the grommet?

I tried lifting the flange with 2 screw drivers under it and everything sort of flexed but no movement. I did not want to pull any harder until I knew more how this goes together.

Is there a trick to pulling on the flange to get it to release?

The floor under the bathroom is bad and needs to be replaced. Thus the toilet flange and black tank have to come out.

Any help, greatly appreciated.

Thanks

John

Here is the flange setup.

[JBarca]

Hi Everyone,

Thanks for the comments. The combo of them helped. Here is what I found.

I hooked up an inspection camera borescope and went into the black tank. This camper has not been used since 2010 was and they cleaned out the black tank before putting it in storage. Some dirt, but no moisture.

Here is the camera work.

Here I am siting down on the job probing job the black tank...


Nice thing about this camera, the display can be remote. It uses a wireless connection to the monitor. It can be on the power handle or by itself.

And if you are wondered what it looks like looking up from the tank into the camper? See here. NOTE: The time and date are off on the borescope. I never made it to updating it.


Amazing this camera can see that far away well. But close up in the tank, it is hard to get it to focus as you are so close to things. But it did what I needed it to.

Here is the toilet flange inside the tank. Ah ha! Threads! OK I can make this work, I think.


While I had everything all hooked up, I needed to find out how the black tank vent pipe connected to the tank. Here I had "thought" they used the rubber grommet. It does not appear that way. It appears glued the tank vent pipe into the tank with no fitting. At least from what is inside the tank. Will know more when I drop the black tank.

Fishing around with the stiff flexible camera cable was not easy. I had to add a cable extension so I could go into the tank deeper. And I had to go on the roof and measure the vent pipe in order to figure out where in the tank to start looking. I tried before I measured and came up dry, could not find anything. After not finding anything, I used the vent pipe dimensions and found an approx area. I used a flash light and looked in the tank by eye saw one corner of the vent pipe. That and the dimensions allowed me to find the vent with the camera.

Once I found the right area, I put a flash light in the top of the pipe on the roof to shine down so I could look for the light. This helped.

Here is some numbers on the top inside of the tank left over from manufacturing. Have no idea what 143 is for


Here is the top edge of the tank. I needed to use that seam to follow it down the tank.


The middle of the tank was a big blur. See here


Globs of ABS glue squirted in the tank from bonding the top on. These tanks I believe are thermoformed as an open top and then a top lid bonded on.


And the flash light shinning down the vent pipe


And the side of the vent pipe in the tank. It looks like the vent pipe is welded in the tank directly. Will know for sure when we take the tank down.


This camera work took over an hour. The toilet flange went quick, 10 minutes, but the tank vent was searching in the dark with a head light on... but we got er done.

So with this, I had a preconceived notion that 3" threaded fitting on the toilet flange was going to be a bugger to get out. I did not want to damage the toilet flange so I stopped and made a spanner wrench to be able to turn the flange on all 4 bolt slots at once. It took me an hour to make the tool but it worked great!

The spanner wrench. The top side I can put a large socket on. I made this up of left over steel and a large bolt I had laying around.


The bottom with 4 bolts sticking out as pins. I can adjust the depth of the pins and needed too. The toilet flange was not flat.


The wrench on top of the floor flange
The flange itself showing the 4 bolt slots the spanner works on




And the tool in action.


And within 30 seconds after this, the flange was out. Yeh!:grin: I thought for sure this was going to come out hard.


Here is the flange and pipe


They used ABS glue and screwed a pipe nipple into the flange. This is why we saw cement on the top of the flange. I think they wanted the pipe to be part of the flange and insure the pipe would come out of the tank.


Here is the female thread flange welded in the tank


So this is how the toilet flange connects to the black tank on a Sunline 2004 camper.

Thanks

John

[dougrainer]

There are only 2 ways the 3 inch DOWN pipe is connected to the Black tank.
1. Rubber Grommet and the 3 inch pipe slips into that Grommet
2. The 3 inch down pipe is threaded and you have to use a long pry bar between the 2 closet bolts '/, in the flange to break the pipe loose.
I have NEVER seen one glued from the factory. Gray tank inlets yes, but not black toilet down pipes. Doug

[valhalla360]

I can't guarantee someone didn't glue it in place but we replaced the same part a few years back and it just screwed into place than then a couple screws to keep it from unscrewing.

[Gjac]

I would make a spanner wrench that inserts into the opposing slots and 2 wedges that you can tap between the floor and flange. Rotate the spanner wrench while tapping on the wedges, it should come out.

[eHoefler]

You can replace the floor without removing the flange, done it many times, including in RV's. It is most likely solvent welded in, and the only way to remove it is to cut it. If the tank is tight against the floor, yu may not beable to glue it back together without replacing everything from flange to tank flange.

[midnightsadie]

I think he,s right,I,d cut just the flange in four sections and try prying one piece out .

[Joe_Way]

If it's like our trailer, the flange is glued to a piece of 3" ABS which is inserted into a rubber gasket.

The ABS no doubt has a coating of scum on the part exposed inside the tank, and is resisting. Just need to pull harder while turning the flange. Worst that can happen is that the gasket gets torn up, but they are cheap.

CLICKY

[MrWizard]

take a good look inside picture #2

i don't about you guys

but to me that looks like the flange was glued to pipe with black ABS cement
IF so its not coming out of there with out cutting things apart

might want to get a plumber to give an opinion

a grinder or a saw will cut
BUT how do you get the new pieces back together with out leaks
won't be able to slip a new flange stem over the existing flange stem still glued to the outside or inside of the pipe
will have to 'BUTT' them together and use and inside nipple to glue everything together (if you cut it apart)

[mobeewan]

It could either have a grommet or the pipe could thread into a fitting that is either glued or spin welded to the top of the tank. Mine appears to be one of the threaded types.

I could get my hand between the tank top and the under floor insulation with breathable membrane covering far enough to touch the pipe. There was thread sealant on my finger tips when I pulled my hand out and no it wasn't poo and the trailer was new.

I didn't have one of the flexible cameras then but if you have one you might see if you can use it by either bending it and inserting it through the top to check or you might be able to fish it between the tank and under floor material like I did my hand..

[j-d]

More likely than not, it will unscrew. See if you can rotate it counterclockwise. Tank will probably have a "donut" bushing for the vent pipe, but the flange will probably have a male or female thread.