So, two possibilities - I somehow screwed up the O-ring and or setting the fitting when I put the new high pressure line in, or there's something wrong with the pump and no amount of me messing with re-doing the line will fix the leak.

I can see that the thing is leaking at that point - where the hard line meets the pump.

So, do I get a new pump, or another new hard line? or both?

 

Clean the dirt and crud from the area and then start it up and see where the leak is coming from.

 

It took me 3 tries to get my new pump to stop leaking, I replaced it with a quality o-ring and it stopped.
FYI there are both SAE and Metric o-rings.
It only takes to snug up the nut, the seal is the o ring and does not have to be so tight that the line does not move.
I do not like o-ring fittings on hydraulics.
Jim

 

this is helpful. thanks. I decided to get a new pump AND another line.... and I'll check into the O-ring much more carefully this time.

 

O-rings are a bit more complicated than I ever thought. I was trying to find a particular o-ring that had probably shrunk over the years. They have 3 dimensions important: Circumference external, circumference internal and the girth of the rubber (which determines both of the above)...Mark