I did this three weeks ago on my W50. Same pump basically.
Access was the real problem but it is a straightforward job.
Remove all lines (4 injector, two low pressure from the secondary filter)
Remove throttle and stop linkage
MARK the timing, best way is to scribe a line from the pump flange to the mounting plate. Mine actually had a line on the pump flange and a movable arrow plate on the motor
. I simply lined these back up when I reinstalled.
Remove the three flange bolts and slide the pump backwards. The splined drive had a single
King spline on mine so it could only go in one way.
Reinstall, bleed and start. I did all this at anchor
in Sausalito which added a bit of stress.
I was offered the option of just fixing the dripping shaft seal
which would have been way cheaper, but after all that effort and since I am off to the S Pacific I went for the full rebuild
. I have a friend in the UK who has actaully done this himself on his tractor, but I would not recomend it as cleanliness is vital and the potential for error is high (Changed the shaft O ring)