Hello, I have a 1958 or 59 641 I think, it has a hydraulic lift, PTO, and 4 speed with a perkins diesel motor, my dad got this tractor from the original owner in '73, my brother drove this thing in the ground, he thought it was a bulldozer, and it set out in the weather along time, anyway, In was reading some old posts and decided to join,this is what I got going on, milky air bubbles, and only have one bleed valve, used to run for 10 min before lift would work, pulled off cap under seat to look at ram, fluid is clean, and about 5 tiny air bubbles, but no other movement than that, my need the pump rebuilt, any help would be good, my dad and I were trying to fix it but he got sick and passed away last Aug.Just need to pick somebody's brain, thanks