I've been battling a hydraulic problem on my 3320/300cx loader for awhile. I blew a steel line connected to the loader valve and replaced all four lines. I also rebuilt the bucket cylinders twice because I cut a seal on the first attempt. 2nd go round they were ok but still had a slight internal oil bypass but not bad enough to worry about it. The issue now is the the bucket cylinders lock up when trying to roll back the bucket. If I apply light pressure to the valve handle while the tractor is at an idle and the loader is raised up, I can get the bucket to rollback slowly. I found a piece of cylinder seal in a quick disconnect fitting and cleared it, the rest of the seal was accounted for. I though maybe there was something else plugging the system. I've cleaned out the entire loader hydraulic circuit, including removal of the valve, disassembling and reassembling. The problem is only on the bucket cylinder circuit. Any else have a similar experience? Is it possible the cylinders are hydro locking with a slight amount of oil by pass? New cylinders are $300+ a piece and new valve is $1300.