Dometic 320 question

[Wicked ace]

A question for those that may have replaced their john with any Dometic or Sealand 300 series toilet. I have a 320 that will not retain water in the bowl. I installed it last winter before heading south in Febuary and it worked fine, I was real pleased. I went out in mid June and found the bowl wasn't retaining water to seal it from the tank, it slowly leaks past. Sitting in the driveway and while camping two weeks ago I could sometimes get a whiff of the septic tank especially towards the end of the few days I didn't sewer hook up. It is not the seal, I went though it all, even replacing it. I repeat, it is not the seal at the tank ball. I did find the tank ball arm, opposite the foot pedal side has some play when pushed down. Looking further I found that side of the ball has an 8" or so long arm that has a pivot recessed into the downshaft of the toilet. It floats free in there and I think it should be a solid press fit. I would think there should be a bushing or grommet to keep it centered and that would keep the ball tight against the seal. I'm wondering if in cleaning the toilet, trying to be sure the seal was clean I may have dislodged any bushing. I have searched for a diagram of the toilet but all I am able to find are ones of the replaceable external parts like the seal, water valve and vacuum breaker. I tried to call Dometic too but that is an exercise in futility.
If any one could please: verify if there is or is not a bushing on the pivot of the arm opposite the foot pedal and if you might know a part number or better yet a diagram showing such an animal. TIA

The manual I saw can be found here:https://www.dometic.com/en-ca/ca/pro...#documentation

[Wicked ace]

Better to be lucky than good. When I set up this afternoon I fussed with the seal a bit and now it holds water in the bowl. go figure

[jneubig]

Mine does the same thing periodically. There are several online articles about this and what to do. I put on the rubber gloves, open the ball valve and run a finger around the black seal pressing down. Works for a while, then it's all over again. I have not swapped the seal but really don't know what that would help as the rubber is still pliable and soft.