It's #21. I just completed most of my power steering rebuild and got ahead of myself and forgot some things after taking breaks, just need someone to clarify where this o-ring is supposed to go. Thanks

 

It shows the location right there in the diagram. I've never rebuilt that exact pump before, but those diagrams are usually quite accurate

 

I ended up downloading the tech manual and clarified it just goes over the fitting that bolts to the end plate. The diagram makes it look like the o-ring goes inside the power steering pump assembly, which it does not.

 

good to know, thanks for the update