I have an ebay replacement on my 750, I had to fight leaks (not shutting off completely) and found that the fiber washers had been replaced with lockwashers, and the knob wasn't flat on the back. Most of the rebuild kits on ebay have lockwashers as well, but there are a few that come with fiber washers. Imho its hard to buy a rebuild kit when a complete valve is just a few bucks more.