Hope this is a more relevant thread mr moderator....
High pressure o-ring part number is #19188397, and it is made from Vitton Rubber.
For all those looking for pictures try
Power Steer Pump Overhaul - Holdenpaedia
notes:
- no need to bash the pump to have all the bits fall out, once snap ring is out just diesect the pump with pliers carefully.
- mounting bolts are different lengths, note where the short one comes from.
- If you stuff it up, a recon pump is $65 from our friends at Just Commodore Spares in Thebarton, SA (Dec 2015).
Cheers blokes!