My trailer has Owens (now Dupree) Products valves. They are 25 years
old and all they need replacd is the shoe seal (rubber part) and
maybe a couple of O rings. Two screws hold the valve internals in.
If you don't want to wrestle with working a new seal in, the whole
paddle isn't much more.
This valve has been in production for over 35 years and is being
used in the food industry. Newell uses it, also Greyhound.
Al