boom packing diagnosis

 need some opinions here; I have a problem with my HD7G in where after raising the boom, it settles down a ways but then holds normally. If I then move it up or down, it will once again settle a ways then stop. Now, accompanying this, the boom control will get "frozen", and require a lot of force to move it, then be normal. If I keep using the boom control and not let it sit, it works pretty much normally. It feels like a hydraulic lock. When I got this tractor the controls were almost frozen solid from disuse. I did the hose check on the lift rams, and fluid will force out under pressure from the head end, so I believe I have a bad packing. I just thought that a bad packing wouldn't cause the drop and then stop; wouldn't it just drop at about the same rate all the way down? This leads me to believe I have two problems, the packing and something in the valve body bad. I'm going to try to power these rams up one at a time (possible with my MF tractor aux hydraulics) to isolate the bad ram. I guess I could just block one ram lift hose and use the shovel hydraulics. Heck, it might be both rams, but it's so hard to do major service at my ranch that the avoidance of extra labor is critical. Any help would,well, help. 

     Yeah, Dave, I agree with that, probably that spool check valve not working smoothly. I do get a bit of that hesitation/slight drop before the boom lifts. Lifting speed seems alright, although I have no other machine to compare with. Add to it, the detents in the boom control are not well defined, even weak.

One other possible is trapped air, I have bled out hydraulics on a few older Cats that did that and cured the problem, you cannot always expect the system to flush out air pockets.