Combines Header wont lower

tbran

Guest
when the lower switch is energized 12v goes to the lower coil only - make sure only one coil is energized a shorted wire will energize raise and lower at the same time. The coil is then energized and the primary poppet is pulled off the seat allowing oil to unseat the second stage poppet which is the determinate of header lower as travel is limited by the adjusting screw. Now either the flow through the valve is limited by obstruction, or the second stage poppet is not moving due to trash OR the oring in the bore of the blokc is sticking the second stage poppet. This oring had been replaced by a square cut oring to prevent binding. Either way replace it as it is on the outside and easier to get out and repair. Finally the possibility of a restriction in the metal lines such as a pinch is possible as well. Hope this helps.
 

NDDan

Guest
Couple things that could limit voltage_currant to lower coil. Switch in handle,safty two terminal oil pressure switch on engine, the wireing and perhaps wire where it is crimped to l shaped connector right at the coil (if wire has been beat around with mud or something coming off of tire). Could run wire to cab to check voltage at coil when it won't lower or have that wire where you can short to cab solinoid when it won't lower. A restriction as tbran mentions could be the .030"+- orfice in the lower side of valve. The restriction accross this orfice is what allows the pressure differential accross second stage popper tbrans mentions and allows it to open as far as the rate of lower screw allows it to. I would be checking this orfice to see it isn't loose in threads or partially plugged. I have seen the spring that pushes on second stage poppet to be broke a few times. This could be limiting stroke of second stage poppet or binding it. These springs were left out of either raise or lower side of valve at one time so if yours is broke I would leave broken spring out until you get new spring and give it a try. The seat for second stage poppet on the lower side is likely loctited in and have not heard of one ever moving but if it has it could have similar affect with the lowering side as it does with raise side as you have likely read about hear in the past. If seat moves with poppet on raise side it will cause very slow lifting and likewise if seat moves with poppet on lower side it will cause very slow lowering. I would venture a guess that if poppet seat is moving you may have a header leak down situation also.
 
 
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