9520/UR3 Hydraulic relief valve

I have a 9520 that I recently purchased, and have been going through it fixing a few issues. I am having some issues with the 3 point and aux. hydraulics. Both will work, but pressure is low. The 3 point will barely lift a 4x4 roll of hay. I have cleaned the inlet screen, and checked the return filter. I have a new filter coming, but neither were very dirty. I cleaned the magnet. There were some cuttings, but nothing worse than normal wear. Tractor is showing about 1500 hours. I also pulled the relief valve to clean it. Didn't notice anything out of the ordinary, however, there seemed to be 1/2 of an oring between the inner and outer barrel of the valve. Spoke with my dealer, and he will be shipping me orings for the valve. Anyone have one of these apart? My service manual shows the orings, but not much detail or procedure for repair.