Please allow me to post this under restoration and not hydraulics since it is an older and specific tractor issue.
5 years ago, I restored my 1948 John Deere Model B inside and out. Sandblasting every nut, bolt, washer and component that would fit in my sandblaster cabinet. I got everything working, even the hydraulics. For 3 years after restoration, the tractor did some parades and some work around the house, but mostly stayed in the garage. I pulled out some small trees, 4X4 fence posts and T stakes. Hydraulics were working great.
Then, what seemed all of a sudden, the hydraulics started to NOT work and the deferential started to fill up with hydraulic fluid. I noticed the hydraulic fluid was going down and differential oil going up.
I figured the packing, oil seal (A2436R) had gone bad, so I replaced both. But within a week, the hydraulic oil had migrated into the differential again without even working.
What is the secret? What did I miss replacing? Trouble Shooting section in the Powr-Trol Service Manual does not mention oil leaking into the differential as one of the problems. My oil expense is starting to go through the roof.
I noticed the bearing, oil seal (A2480R) was tight in the housing and showing very little ware. I suppose the cup, oil seal (A2432R) is suppose to spin on the PTO shaft, but then what is the purpose for the 2 packing oil seals?
My hope is that someone remembers the secret to this and will share with me.