2002 power Steering issue

[Jammel96]

I changed the power steering pump in my 02 SIerra 1500(4.8). It was a complete pump and I installed it, but it is leaking where the high pressure line goes into the pump. It looks like it is leaking between the line and the threaded nut.  I installed the included O-Ring on the line.  There was another O-Ring that came with the pump that is slightly bigger than that one.  Should I have put this ring inside the fitting for the high pressure line or is it something else.  Any help would be much appreciated. 

Thank you