The bowl has come loose from the base of the toilet in my motorhome. The bowl is porcelain and the base (with the flush valve) is plastic. Looks like I will have to remove the toilet and turn it over ...
I just went through this wonderful experience with the dometic 511. The plastic floor flange broke due to rusting bolts that hold the toilet down. It's a rubber gasket between the toilet base and the floor flange.