I have a 3 pt bush hog 762H backhoe attached to a 790 JD. I got a UFO in the system and all of the spools started leaking at the handles. After the UFO left I still have a leak at all handles. slow leak now does this require a complete rebuild or is there a o ring on each spool that can be replaced? it will be a big job taking the control valve off of the backhoe/
Bush hog brand 762H backhoe spool leaking
- Thread starter james360
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LD1
Epic Contributor
What are you referring to as a UFO?
Spool valves that leak out of all the handles is a sign of back pressure (over pressurization) on the tank passage of the valve.
Backhoe AUX loops arent typically plumbed with a PB loop. Because they arent designed to be used in conjunction with the 3PH. Most backhoe attachments manuals (especially if you have the MFG's backhoe for the tractor) specifically tell you to lower the 3PH lever all the way and not to move it.
Raising the 3PH lever takes pressure....that pressure is seen on the tank passages of the new valve. Normally not an issue cause it takes little to no pressure to raise the 3PH with nothing on it. BUT.....if the 3PH arms are left on the tractor....they can bind into the backhoe frame and cause full pressure. So can a slightly mis-adjusted feedback rod and when the 3PH physically gets to the top of the stroke it is still trying to lift. Again, that causes full system pressure on the backhoe valve tank ports and will cause the exact issue you have.
Dont know the layout of the valve, and whether it would be eaiser to remove to replace the seals. Each spool will have two seals. Sometimes o-rings, sometimes quad seals or x rings. (look like o-rings but not a circular cross section). There will be one on the side the handle attaches to, and one on the opposite side under the "can" where the return spring is. And there is a chance that you have also cracked the casting. So look that over good before you spend time and money replacing seals
Spool valves that leak out of all the handles is a sign of back pressure (over pressurization) on the tank passage of the valve.
Backhoe AUX loops arent typically plumbed with a PB loop. Because they arent designed to be used in conjunction with the 3PH. Most backhoe attachments manuals (especially if you have the MFG's backhoe for the tractor) specifically tell you to lower the 3PH lever all the way and not to move it.
Raising the 3PH lever takes pressure....that pressure is seen on the tank passages of the new valve. Normally not an issue cause it takes little to no pressure to raise the 3PH with nothing on it. BUT.....if the 3PH arms are left on the tractor....they can bind into the backhoe frame and cause full pressure. So can a slightly mis-adjusted feedback rod and when the 3PH physically gets to the top of the stroke it is still trying to lift. Again, that causes full system pressure on the backhoe valve tank ports and will cause the exact issue you have.
Dont know the layout of the valve, and whether it would be eaiser to remove to replace the seals. Each spool will have two seals. Sometimes o-rings, sometimes quad seals or x rings. (look like o-rings but not a circular cross section). There will be one on the side the handle attaches to, and one on the opposite side under the "can" where the return spring is. And there is a chance that you have also cracked the casting. So look that over good before you spend time and money replacing seals
By UFO the loader quick connect got knocked loose several times and the back hoe lost functions it had a blockage it was crazy leaking from major pressure. i took the hoe loose then the loader started having issues. the suction screen was stopped up. everything is working now with small leaks at all backhoe spools. not sure where to go now that is why i posted. when i hook the backhoe up the three point is all the way down and I do not try to lift it. I added a factory option power beyond to get flow to the the hoe. i am in Alabama got the last one listed by dealer, it came from New Mexico, The valve is open center constant flow. the hoe is old and abused but works good for me, had no leaks when i bought it.