from your pic, working left to right maintaining orientation as you have them laid out plunger srping then the retainer.
If you look closely at them you will be able to see a ring on the face where it sits on the seat when the engine is off and the spring will have left wear marks on the 2 places it sits on the retainer and the plunger.
from memory thats not the primary pressure relief valve but the flow regulator valve.
IF the wear marks do not line up with assembly as ive described it Phone me and I'll dig out the workbook on hydraulic pumps and get it out of there.
(pm with my details being sent)

