annoying leak

so finally replaced my leaking power steering system. new pump, box, and supposed to be new lines. well the pressure line i got from rock was wrong, so ended up being able to reuse the old one for now. my problem is the adapter or outlet piece on the box for return keeps leaking. ive cleaned and replaced the orings but its still leaking. is there a a good way to seal it? was thinking rtv or maybe gasket maker. just need it to stop leaking