Combines Hydraulics really slow when warm

The spring and ball your talking about is probably the the by-pass, not for sure. I worked on a friends tractor that was doing the same thing. I found out that his hired hand changed the hydraulic oil, he removed the wrong plug, which had the ball and spring behind it. They ended up in the bucket and he never knew the difference. That spring usually has shims to adjust the pressure. I hope this helps

when you had the pump apart, did you notice if there was any very tiny grooves worn into the brass inserts on either side of the gearsIJ Usually when you lose hydraulics as the oil warms up it is becasue there is a small groove in the brass, or the tollerances between the gears and the housing are opening up due to heat expansion. check it again and see if there are any grooves you can catch your fingernail on. and use a feeler guage between the housing and the gears, you shouldn't be able to fit a .003" strip between them.

I'll have to tear it apart to check that brass wear plate and the tolerances today. Thanks for the info!