Stock 914-6 oil union leak

[xsurfer]

My stock six won't stop leaking at the union between hard line and rubber line
that attaches to the oil tank.

Is there a known fix for these fittings? Is the hard line more suseptable than the rubber fitting? The stock fittings are aluminum with thedate on them. My car is numbers matching 1971 which I'm trying to keep as close
to orig. as possible.

Thanks