ezspdr, These are "blade" valves, a sliding flat plastic blade sealed with "rubber" sealing rings. These valves may be rebuilt by completely emptying the tank, removing the bolts that hold the valve together, sliding the center portion out, replacing the sealing rings and blade (both are bought in a kit) ( now is a great time to lube everything with plumbers grease, bolting it back together.
2000 Winnebago Ultimate Freedom USQ40JD
, ISC 8.3 Cummins 350, Spartan MM Chassis. USA 1SG, retired;PPA,Good Sam Life member."We the people are the rightful masters of both the Congress and the Courts - not to overthrow the Constitution but to overthrow men who pervert theConstitution. "Abraham Lincoln"