Power steering pressure line o-ring size?

I'm starting to get tired of buying oil ($4/qt) and refilling my RV power steering pretty often.

I already replaced the return line that was just clamped at both ends, so I suspect the leak is from the pressure line at the pump. There is a small o-ring at that end where it connects to the pump:



Has anyone just replaced that little o-ring? If so, what size was it?

The hose is about $18-25 but if a 50 cent o-ring fixes the leak, I don't see much point in replacing what isn't broken. Of course, the hose is probably the original from 1985 so it's probably due for routine replacement.

This is the style of pump I have with the reservoir as part of it:

 

Take the old one off, then take it in to the parts store.

Sent from my SM-N960U using Tapatalk

 

Dealership stocks them, they are a white o ring.

 

If you are referring to what looks like a small black O-ring, I'm not any help. My hose does not have that.

It does however have a small white teflon seal that rides in the top groove near the hex flats.

Here is the package, they are stocked at our Napa and Amazon.



The nut will snug down but the line will still wobble in the pump, that's normal.