Tractor Repair: 1070 remotes quit working, flow divider, hydraulic seals

Question
We were using the tractor to bale. Everything was working well when the back door of the baler failed to raise completely to dump a bale. All of the gauges were fine, and everything else (transmission, brakes and PTO) was working. After manually removing the bale and closing the back door of the baler, we were unable to raise the door again, at all. So far, we have filled the hydraulic transmission fluid to full (took 8 gallons); repeatedly dismantled the flow divider valve, replaced the spring and installed spacers; and, took the hydraulic pump apart, inspected all of the hydraulic seals and O-rings, and found no problems; finally, we blew compressed air through the sump screen. We have no reason to believe the remote spools have failed. Everything has been reassembled and we still have almost no pressure on the remote hydraulics. We can only raise the back door of the baler about 1/3 of the way VERY slowly. We are out of ideas. Can you help?

Answer
  The hydraulic relief valve has probably failed.  Unfortunately, it's located on the bottom of the remote valve assembly, so the remote valve must be removed to get the relief valve out.  The top bolts for the remote valve face the front of the tractor under the fuel tank and are almost impossible to get out (especially on the right side) without raising the rear of the cab or platform a couple of inches.  There are also plastic thermal valves in the remote valve that melt or distort if the oil gets overheated and the remote valve casting has been known to crack so inspect the entire remote valve carefully.