I just remove the oil pressure sending unit and fill the passage with oil,re-install sending unit and it's primed.I did have a problem with the last rebuild and it turned out to be the pump cover O-ring which was brand new but evidently not the right specs.;Cindy @ Motors & More told me they had a lot of issues with these O-rings this year so I guess it's just a bad boatload
.By the way I put my original O-ring back on it solved the prime loss issue
.