I have the same valve and just looked at the info sheet. The shaft O-ring is replacable as are all parts. Kind of a dog to find it but here's the link to the Hayward site:
These things are real easy to take apart. While it's apart inspect the spider gasket too and if that needs replacing there are varying thoughts posted on this forum about the best way to install one. Post back and we'll point you in the right direction. And..I see you only have 4 posts so Welcome to the forum. May it continue to survive.
Hope this helps.