Dometic 300 toilet floor flange replacement

PeteM · 08-13-2022, 10:38 AM

Has anyone replaced the toilet floor flange in their keystone rv? I removed the toilet once and replaced the seal but this did not stop the odor coming up. The bowl rocks a little front to back and I'm thinking the floor flange is cracked or broken. I need to know if the flange is threaded or glued to the tank pipe before I try to replace it.
I've only found one Dometic flange which has a threaded down pipe so I'm assuming that's the correct one. Can anyone answer or address this problem so I can do a proper repair?

**chuckster57** · 08-13-2022, 11:54 AM

Welcome to the forum

Year, make and model of RV will help. If you removed the toilet, did you replace the foam seal?

bobbecky · 08-13-2022, 01:08 PM

Several years ago, our floor flange broke and the toilet was rocking. I installed a stainless steel floor flange on top of the RV flange using #12 flathead screws, and re-installed the toilet with a new gasket. There was room on the bottom of the toilet for the extra flange and the toilet is solid, just had to drill through the plastic flange for the screws. Home Depot shows the flange to be about $6. https://www.oatey.com/products/oatey...ing-2125802336
I would recommend using a couple of speed nuts on the closet bolts to hold the bolts vertical to make it easier to set the toilet in place if you use one of the rings above. https://www.amazon.com/Hillman-Group...ts_id=16410081

slow · 08-13-2022, 01:37 PM

If you have an odour, it is most likely the seal between the bowl and base on the 300 Dometic toilet. It is a known issue and you should contact Dometic for a free replacement.

NH_Bulldog · 08-13-2022, 02:59 PM

Our flange is treaded into the black tank and secured to the floor with 4 screws.

PeteM · 08-13-2022, 03:39 PM

Quote:

Originally Posted by NH_Bulldog

Our flange is treaded into the black tank and secured to the floor with 4 screws.

I have a Passport2820BH so I assume my setup is similar to yours. Thanks for your help.

NH_Bulldog · 08-13-2022, 03:42 PM

This is what I found on mine

PeteM · 08-13-2022, 03:45 PM

Its a 2019 Keystone Passport 2820BH. I replaced the seal but odor still comes up but noticed that the toilet will rock front to back which makes me think the floor flange is broken.

**sourdough** · 08-13-2022, 03:58 PM

Pete this is just an observation but the 300s have a history of issues. If I had one and it was out to do some kind of repair a 310/320 would be dropping back down in its place....if you have room.

wiredgeorge · 08-13-2022, 04:11 PM

I know the 320 tall (that is what I replaced our original commode with) needed a bit more room to the rear. If you read about them, the specs should tell you how much clearance in the rear is needed. The 320 tall is elongated and a bit taller than a standard 320 and really is much more comfy than my original (Thetford Aquamagic - the most miserable RV toilet ever invented).

PeteM · 08-14-2022, 05:15 AM

Quote:

Originally Posted by NH_Bulldog

This is what I found on mine

Thanks Bulldog. I see the flange cracked but also noticed that there was another gasket around the tank pipe. I only replaced the smaller gasket on the toilet. I'll take it apart this week and replace the flange and gasket. I'm selling this RV but need to make things right for the next owner.

Jason.rhodes86 · 08-15-2022, 06:42 AM

Quote:

Originally Posted by PeteM

Its a 2019 Keystone Passport 2820BH. I replaced the seal but odor still comes up but noticed that the toilet will rock front to back which makes me think the floor flange is broken.

You replaced the inner seal between the two bowls already?

PeteM · 08-15-2022, 08:05 AM

I replaced the small bowl seal first but didn't realize that there was another seal on the floor flange. I took the toilet off and discovered a broken floor flange and torn pipe seal. I will replace the flange and seal as soon as the parts arrive. That should fix the problem. Thank You all for your replies to my issue.

slow · 08-15-2022, 09:31 AM

Quote:

Originally Posted by PeteM

I replaced the small bowl seal first but didn't realize that there was another seal on the floor flange. I took the toilet off and discovered a broken floor flange and torn pipe seal. I will replace the flange and seal as soon as the parts arrive. That should fix the problem. Thank You all for your replies to my issue.

Just to clarify: there are three seals; the top most is at the bottom of the bowl and holds water in the bowl after a flush. There is a second seal where the toilet sits on the flange at the floor. The third seal on a 300 Dometic, that has a well documented history of failure resulting in odours, is located between the bowl and the base of the toilet. As others have stated, contact Dometic for a free toilet replacement prior to addressing any issues you may be having with the floor flange.

bdoppel · 08-18-2022, 08:11 AM

Quote:

Originally Posted by PeteM

Has anyone replaced the toilet floor flange in their keystone rv? I removed the toilet once and replaced the seal but this did not stop the odor coming up. The bowl rocks a little front to back and I'm thinking the floor flange is cracked or broken. I need to know if the flange is threaded or glued to the tank pipe before I try to replace it.
I've only found one Dometic flange which has a threaded down pipe so I'm assuming that's the correct one. Can anyone answer or address this problem so I can do a proper repair?

Call Dometic. I had the same problem, called them and they told me the toilet was a recall and sent me a new one.

Jason.rhodes86 · 08-18-2022, 09:58 AM

Quote:

Originally Posted by bdoppel

Call Dometic. I had the same problem, called them and they told me the toilet was a recall and sent me a new one.

Same. Got new one sent no problem. Just make sure to say you’re the first owner if you’re not and they ask. I took it apart and put some silicone between and around the two inner seals that failed on my old one. Will do same to my old one to have as a spare just in case.

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