First I replaced the water flush valve on a 1989 SeaLand then the vacuum breaker needed replacing.
Question/Comment...it appears that the china bowl was formed around the valve.I gave up and bought a new Thetford residential china bowl foot flush, it's 19" high so it will be much better anyway.How the :÷!@"&\%/ can you install a new vacuum breaker on the SeaLand? Anyone know the secret?