B7100 3 pt hitch slowly losing pressure

[dennis52]

The 3 pt hitch on my B7100D (gear) will lift my brush hog for awhile but slowly loses pressure and lowers the implement so that I have to raise it again with the control lever.

The problem has been getting slowly worse over time.

My understanding is that the possible reasons are:

1. A worn oil pressure piston O ring, piston or cylinder.
2. Faulty control valve
3. Faulty spool

Has anyone undertaken an overhaul of the hydraulic lift system and could you advise of the most likely cause and how you approached the overhaul.

[KubotainNH]

My B6100 also drops. I have some sort of chain setup back there though that I can slip into a hook thing to keep it from dropping. Looks OEM to me. I'm pretty sure there's a post on here somewhere about someone replacing the O-ring to fix it, just gotta search for it. I'll do mine someday The 6100 is almost the exact same machine, just a smaller motor.

You can see the chain right below my seat near the top link. It attaches to both lift arms in a V shape.
http://www.tractorbynet.com/forums/a...s-dscf0813.jpg