My 250 john deere booms work and bucket dumps and holds front end up but does not tilt back. Does not work at idle or high idle. When I take bucket off it wont tilt back quick attach at idle but will do it on high idle. I did switch hoses by the right side front cab mount behind side shield. Then when I push toe down on right pedal the bucket tilted back. When I pushed heel down the bucket dumped and picked front wheels off but when you take foot off the pedal the front end goes down?? What is the problem or how can I diagnose this? I did rebuild the main control valve by your feet with new o ring kit Kv 12882 and still does the same thing wont tilt bucket back. What can I check next? No dirt under pedals and they all move the same distances.