$36 from Blackwoods for the really good o-rings that are immune to power steering corrosion...
easy really. think i followed this one....
DIY: Power Steering Pump Rebuild - NASIOC
the gc8 ones would be similar but i would have to pull it apart and see what the od of the rings are.
I will phone blackwoods to get the list of rings i ordered as it is in my old work email...