A lube might help it, but do not use Vaseline, it will break down the seal because its a petroleum based lube...go to a restaurant supply company and get silicone based N.S.F. lube for ice cream machines ect. its cheap and will hold up even in cold...the time to do this was before
the seal goes...but it may still help some...also ambient temps are going to say allot here regarding the tolerances between the mating surfaces of the seal...if the dump door is the sliding type your doomed, one scratch on the door surface and any seal new or not will be cut by the scratch on the door
as it slides past the seal, this sucks as you must R&R the door and seal together...if you have a flapper type of door or a ball valve your in luck...fix it with the seal only. Tolerating the leak as part of your toilets personality is probably cheaper. This is a nightmare when a $$$$ coach comes in under warranty with this issue...We just replace the toilet to get rid of the problem and ebay the old unit out.
Yes Donna, the water only drips until the bowl is about empty--I figured it was a seal problem. I don't have water running continually like a standard reservoir toilet in the home--that would be a REAL problem. Sounds as if one just can't replace a seal without replacing a toilet! And it is only 2 years old!! I will try scrubbing the seal again the next time out. I was also wondering if something like Vaseline might help keep the seal functioning.