New power steering pump O-ring but it still leaks?

[BristolSam16v]

Just fitted a brand new rubber O-ring from renault and its still leaking from that union, and there are no holes in the pipe.

I took the ring out again and it doesnt look distorted or anything, whats going on :cry:

[white16valver]

The union parts are round aren't they, and not oval?

Bit stuck on that one really *shrugs* lol