I am rebuilding valve that comes off the tank on side . This is a 1970 airstream sovereign
30'. Bought the thetford valve ring, etc but missing one piece that looks like a sanitary t but on end there is a plate for 4 screws and on other side of that a fitting with some nubs that one of the other pieces twists onto. I cannot find this strang sanitary t anywhere. Any help? Also where do I get more foam to put around waste tank. Can I replace my fresh water tank from underneath the trailer or do I have to remove the floor?