Dometic 310 leaking between bowl and base

My Dometic 310 (high profile) has been leaking between the bowl and the base. I tried everything Dometic recommends (fill bowl with hot water, replace ball seal, lube seal, etc) to no avail. The water was leaking down the outside of the base at the seam between the base and the bowl. I finally go so fed up with the stinky liquid on the floor I took the commode off and took it apart. It was a real mess. Smelled so bad my wife had to leave and go for a long walk. Wish I could have done the same. Luckily I lifted it straight up off the floor and put it into the storage container I use for sewer hoses. As I tipped it, a bunch of very stinky waste liquid came pouring out. Turns out the injection molded plastic base was holding all the waste water that had leaked from the ball seal and then through the bowl-to-base seal (see photo) into the cavities in the base. The seal may be OK, and the problem may have been caused by the screws holding the base to the bowl not being tight. The cavities had filled up and movement caused by sitting on the commode caused it to slosh out of the cavities and down the outside. Has anyone found a place to get a replacement seal that goes between the bowl and the base? Its the oblong seal in the attached photo. I think I can put it back together for now and won't have it leaking on the floor because it will take some time to fill back up. Would like to pay a few bucks for a seal instead of a couple hundred for a new commode.

I got my ball seal kit from Amazon. They may have yours.

Roller4tan said:

I got my ball seal kit from Amazon. They may have yours.

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I got a ball seal kit at Amazon too. It did nothing to solve my problem. Because the screws connecting the bowl to the base (you can only see them after removing the commode) were not tight, flushing the toilet caused waste water to seep past the bowl-to-base seal into the base. After it filled up, flushing or motion caused by sitting on the toilet would cause this nasty waste water to leak out of the base onto the floor. What I need is the oblong seal that goes between the bowl and the base. I've scoured the internet for the seal and cannot find it. It does not show up on the 310 model parts list. See added attachments. I will call Dometic next week.

I think you can replace the toilet for $127. Amazon.com.

Maybe you can find some atv caulk at an auto supply and coat the gasket. If that stuff holds up to automotive antifreeze, it should hold up to the toilet deposits.

This might be the problem with our commode as well. We seen some seepage out from under the base at floor level. I was wondering if it was the seal between the commode and black tank inlet but this could be it. Have not noticed anything running down the outside of the toilet. Is this an internal leak path?

Regards, John

We pulled our RV out of storage this last weekend. I had ordered a ball seal kit and a floor seal kit. I pulled the commode out yesterday and took it outside to completely clean it. The ball seal groove had lots of gunk in it, the ball seal was feeling a little brittle and the ball had gunk on it. All this was cleaned, a new resilient seal installed and silicone grease applied to the ball side of the seal, per instructions. the floor seal had been mis-installed and got twisted between the floor flange and the commode base. A new seal completely seated on the commode base and the commode was re-installed. Time will tell if the seals are fixed.

Regards, John

I know this is old.. My toilet is leaking at the base also. Wondering if this could be the issue.


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PondSkum said:

I know this is old.. My toilet is leaking at the base also. Wondering if this could be the issue.


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Domestic told me they fixed the design between the time of my original commode (in my 2012 trailer) and when I replaced it in 2015. If you pull it out and hear sloshing when shaken, it's the same problem. Test it over a large bucket. Nasty stuff.

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PlanoTXBill said:

Domestic told me they fixed the design between the time of my original commode (in my 2012 trailer) and when I replaced it in 2015. If you pull it out and hear sloshing when shaken, it's the same problem. Test it over a large bucket. Nasty stuff.

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I know this thread is old, however I noticed my toilet weeping between the bowl & base. We’re you able to locate the seal or did you purchase a new toilet?

TIA

Sandpirate69 said:

I know this thread is old, however I noticed my toilet weeping between the bowl & base. We’re you able to locate the seal or did you purchase a new toilet?

TIA

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I did locate the seal, tore it down, cleaned it out (was disgusting - think fermented human waste), put it back together. It failed again a few months later so I bought a new one. No problems since.

PlanoTXBill said:

I did locate the seal, tore it down, cleaned it out (was disgusting - think fermented human waste), put it back together. It failed again a few months later so I bought a new one. No problems since.

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Thank you for your response. I’m going to order one tonight. I’m going to try and use silicone for the time being. Just need to get through the long weekend.

once again, thank you for your fast response.

PlanoTXBill said:

I did locate the seal, tore it down, cleaned it out (was disgusting - think fermented human waste), put it back together. It failed again a few months later so I bought a new one. No problems since.

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Did you buy new toilet or seal?

Can I get a link to purchase the new seal for the 310?

some of the toilets were made inproperly , wernt joined together correctly , buy a new toilet , problem went away