Toilet Seal does not hold water

There is a tag with RFID code on it but it is not very visible since it is stuck under a part that obstructs it.

Deleted.

I don't know how many manufacturers there are for RV/marine toilets. Couldn't be that many. Go to Thetford http://www.thetford.com/HOME/PRODUCTS/PermanentToilets/tabid/76/Default.aspx
and see if you can match descriptions. Hard to say how many changes have taken place in the last decade.
My Thetford toilet had a stick on bar code with Mod. # and description. It was located on the underside of the bowl..door side. Thetford uses the "sun with rays" to replace the "o" in Thetford........could have been a change with time.
Good luck.

My toilet has NO name on it but has a symbol, it is blue backround and bottom half of a sun with rays. Is that Thetford?

OK, I have used the Olive oil and brushed, used a hanger to try to clean the "groove", have used copious water and toilet brush, still no water stays in toilet SO guess I need go to RV repair place which sucks but I cannot do this myself, just had a mastectomy and cannot lift much of anything right now. Anyone live in eastern MA who knows how to do this change out of the gasket?

I did it Harold's way. New seal and I am kicked back. Sea Land makes some models that you just reach in there and change the thing out.

HOLD THE PRESSES....my work paid off. Seal has now seated in. Holding water in the bowl. YIPPEE.
I like the swimming pool lube and I will be obtaining a "stool tool".
Happy camper again.......not to mention better half.
Thanks all for the thread and comments/recommendations.

If aquamagic sl, sh ,gl , or gh model toiler with 2 pedals at 5 oclock position, you have debris in nylon slider path, Thetford tool 33011 bent screwdriver will clear it out without disassembly. Or use long l shaped allen wrench with visegrip on long end and get short end of allen wrench horizontal and open slider with foot pedal and insert tool at 5oclock pos. and turn visegrips clockwise swiping debris out of just below rubber seal in the path that the slider goes. Just do not drop it into toilet or waste tank! Thetford tool works best and any dealer in the know will know about it. You will find this tool works for handymen for a lot of uses.

I use Swimming Pool lube on the seals, it's basically a silicone based lubricant that is used on swimming pool pump O-rings and such..