I have a 1965 Galaxie 352 engine. I have a leak of the high pressure power steering hose as it connects to the pump. I have purchased new hose from Dearborn Classic. The flange on the end of the hose fits to the male fitting on the pump. I tighten it down and the new hose still leaks when steering is turned lock to lock.
I then tried to tighten the nut further thinking the flange need to seat harder to the male fitting. Still leaks, less but still leaks. Seems odd that this is a metal to metal connection so of course they must fit perfectly. But how could this wear out?

 

When you get something like this there could be several possibilities of where the leak is really coming from.
If the end of the replacement hose fitting has a different angle flare it will never seat correctly. Some fittings had a 37 degree angle and others had a different angle again enough to cause it to leak.
If either the fitting on the hose or the pump has a hairline crack at or near the sealing area it will leak under pressure. What sometimes helps to pinpoint this type problem is to dry the area with some brakekleen then dust a little talc powder over the area.
Parts like fittings don't usually wear out, but they do crack from excessive tightening or fatigue.
Also , when the steering has reached the end of it's travel, some systems will allow the pressure to go to a by-pass mode so as to not burst hoses etc.
Let us know what you find, thanks