Black Tank Leaking at Top Connection From Toilet

[tld]

I have a 2016 27.5 fifth wheel and my black tank has developed a leak at the top where the toilet standpipe connects into the back tank. I am trying to determing if Jayco used a compression grommet to make the connection. I can see some silicon grease around the connection which makes me think that they greased up the standpipe and inserted it into a rubber compression connection. I'm wondering if I can removed the toilet and take out the toilet flang screws and then pull the standpipe out of the rubber connection to replace the rubber connection. Does anyone have any information or experience with this issue?

[Grumpy]

The stand pipe should be screwed in. I had one crack and replaced it years ago. Removed the toilet, then the flange and then the pipe.

[Nature Ist]

I had the same problem on a 2007 model, though it was the vent that was leaking. At that time, and in that particular unit, there were no threads or fasteners holding the ABS pipes, it was simply put through the hole (though it was a snug fit) and sealed with a special sealant. Perhaps because it was a travel trailer, the only option was to drop the tank and re-apply sealant to both the 3" waste and the 1 1/2" vent pipes. I somehow got it to work, but I remember being stymied by how flimsy the factory install had been.....and that was 2007!!!!!
My 2020 27.5 fifth wheel does seem to have a flange of some sort, but I think it's a gasket that has a flange with screws securing it. It may be that fifth wheels are easier to access from above.
I just looked at the plumbing schematic I have for my unit, it does reference a threaded 3" nipple on the bottom of the standpipe. As Grumpy stated, based on what my schematic shows, you should be able to remove the toilet, unscrew the floor flange, and then unscrew the standpipe.
If you are unsure, I would think Jayco could tell you from your VIN # what they used on your unit.
Let us know how you make out!

[Rustic Eagle]

Originally Posted by tld

snip...... Does anyone have any information or experience with this issue?

The following pics are taken from my plumbing diagram/parts listing for my 2018 24RBS..., the actual document is dated 2015 and 'should' cover your 2016 model year as well. I would assume the toilet floor flange (Item #11) and attached nipple (Item #13) are typical toilet applications with Jayco. The black tank vent pipe is also shown. I don't have any reference info for the tank inlet itself.





Hope this helps.

Bob