I had the same problem trying to reconnect the lines to the backhoe on my T25. One went on just fine, but nothing I could muster would let me reconnect the side with the check valve on the loader hydraulic line. I was advised to crack the Pioneer fitting loose from the line just a little bit to let the pressure out. That did the trick. Evidently the backhoe sitting out in the warm sun for a few days might have increased the pressure in the line. I had tried moving the rear remote control valve but it didn't work for me. I have since purchased two hydraulic line pressure relief tools...which are nothing more than a male and female Pioneer coupler with the internals removed and replaced by a threaded bolt. Retract the bolt completely, attach the tool to the fitting and then screw the bolt in until the pressure is released. Simple and effective. These could be made at home if one already had the fittings--I didn't so I simply purchased them.
Kim