I just to rebuild my pump (Perkins not Yanmar). Given that your bearings
failed, just realize that is a more difficult task than simply replacing
the o-ring seals. I used a ball joint press kit from an auto parts store to
press the bearings, but it was far from a smooth operation. My thought
process was that, for $35 - $45, it was worth an attempt before I committed
to $250+ for a refurbished pump.