I may be looking at this wrong, but....

From what I can see the leak is at the point where the pipe comes out of the 'nut'. If this is the location of the leak then there is nothing to do but replace the hose since the pipe is cracked or bent.

The O-ring seals inside the orifice and the pressure goes through the pipe. If the leak is coming out where the 'nut' screws into the rack, at the threads, right up next to the rack, then the 0-ring is not holding and needs to be replaced.

If the oil is leaking from the back of the 'nut' where the pipe goes into the retaining nut there is a crack in the pipe itself where the 'nut' has rubbed a hole in it.

These have to be installed dead on center and there is no room for error. I like to line them all up, screw them in finger tight if possible (making sure they turn freely) and then mount the rack and pinion to the body or other mounting points. Then it is just a matter of a final turn or two with a wrench.