Power steering box inlet

[66chargertoy]

So I have had to change the return inlet of my power steering box to match the Saginaw pump because of the early 66 style return is quite larger then the later configurations. This is the aluminum piece that sits on top of the steering box on a power unit where the return hose of the power steering pump goes. Problem is, it keeps leaking where it attaches to the unit. Is there a special "O" rings that go in between. Also, what the hell is the spring that is inside for  . A friend of mine had a extra one, but it turns out that the spring inside was toast  . Do I still need this spring?