I replaced my control valve. My external hyd. works to open grapple,but will not close. Did for a while,thought my problem was solved. Worked about ten times,then quit. When I push my switch to open pressures up,push the switch the other way,nothing. With losing all the fluid think I might had some trash break lose.
Are you saying you replaced the entire hyd control valve? Don't think I've heard of anyone doing that. Hmm. The aux hydraulics work by solenoid valves on the main control valve. You could have a bad solenoid, could be the control switch, could be a wiring issue. Have you tried switching the wiring connectors to the solenoid valves? Then down would work up and up would work down. If the grapple now closes, but not opens, probably a bad switch or problem with wiring.
Actually, I had a leak in the control valve. Bobcat wanted twelve hundred dollars to take it off,rebuild it,and put it back. I took it off and reinstalled it. Everthing worked fine before. The solinoids are color-coded,dont't look like you can switch wires.
First off need to eliminate the electrical system- switch, controller, solenoids, ect. Its very easy to do as ATCO said. An easy thing you can do if nothing seems to work is to turn key on- don't start, turn on aux, raise cab, loosen aux stem nuts, and run aux rocker switch. If electrical is o.k. when you rock thumb switch left or right, try to slide each coil off stem. If power is being sent to them, they will become magnetized and you will be able to feel resistance.
Did the electric test. One coil is good,other seems bad. I' not getting power to the one that's not working. Took the good coil put it on the other stem,doesn't work. Used a test light,no power on one.