Hey guys, been awhile since I have visited and now I have a question I hope someone can answer. I have a bush hog m446 loader on my m6800 kubota and the bucket leaks down rapidly with or without a load and running or not. I switched the hydrolics hoses of the bucket over to the lift arm connection and the loader hoses to the bucket connections and have the same problem. The loader arms do not drift regardless of which side I have them connected to but yet the bucket continues to drift irregardless of which connections I hook up to. I assume that means I have a cylinder seal bypassing but there is no visible evidence of leakage. Can you advise, thanks
Bush hog loader leak down
- Thread starter texoak51
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davesl708
Elite Member
Very likely the orings on the rod inside the cylinder allowing bypass.
Soundguy
Old Timer
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yup.. can take off the no press hose side and look for bypass leaks as it leaks down.
Soundguy
Old Timer
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- Mar 11, 2002
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- Tractor
- RK 55HC,ym1700, NH7610S, Ford 8N, 2N, NAA, 660, 850 x2, 541, 950, 941D, 951, 2000, 3000, 4000, 4600, 5000, 740, IH 'C' 'H', CUB, John Deere 'B', allis 'G', case VAC
Are you aware of how a double acting cylinder works?
Cylinder with 2 hoses.
Oil is pushed in one side under pressure, lets say, extending the rod. The area around the rod has oil, and it is pushed out of the cylinder as the rod and piston move to extend. That oil is dumped to the tank under virtual no pressure. . Now, you can reverse tho and push oil back in that port, and exhaust it out the other side. Pressure and low pressure sides swap depending if you are extending or retracting that cylinder.
Now, say we extend it. One side is under pressure holding the weight of whatever the cyl is holding, while the other side of that cyl is open to sump thru the spool.
Taking the hose off the low pressure side of the cyl, then lets you see if oil I bypassing the cyl internal packing.
IE, if you extend cyl under load,remove Lo pressure hose, see cyl dropping, and oil is pouring out the low pressure port as the cyl drops, you know the packing I blown. For twin parallel cyls, even if only 1 has blown packing, both will exhaust thru the blown one.
That clear it up any?
Cylinder with 2 hoses.
Oil is pushed in one side under pressure, lets say, extending the rod. The area around the rod has oil, and it is pushed out of the cylinder as the rod and piston move to extend. That oil is dumped to the tank under virtual no pressure. . Now, you can reverse tho and push oil back in that port, and exhaust it out the other side. Pressure and low pressure sides swap depending if you are extending or retracting that cylinder.
Now, say we extend it. One side is under pressure holding the weight of whatever the cyl is holding, while the other side of that cyl is open to sump thru the spool.
Taking the hose off the low pressure side of the cyl, then lets you see if oil I bypassing the cyl internal packing.
IE, if you extend cyl under load,remove Lo pressure hose, see cyl dropping, and oil is pouring out the low pressure port as the cyl drops, you know the packing I blown. For twin parallel cyls, even if only 1 has blown packing, both will exhaust thru the blown one.
That clear it up any?
oldnslo
Super Member
Simple test:
Lower the loader fully and relieve the pressure in the curl circuit. Unhook the curl circuit quick disconnects. Raise the loader, does the bucket still dump? If yes one or both tilt cylinders need to be rebuilt / new seals installed.
Connect cap or blind end hose before lowering the loader. This will make connecting the rod end hose easier once the loader is lowered.
Lower the loader fully and relieve the pressure in the curl circuit. Unhook the curl circuit quick disconnects. Raise the loader, does the bucket still dump? If yes one or both tilt cylinders need to be rebuilt / new seals installed.
Connect cap or blind end hose before lowering the loader. This will make connecting the rod end hose easier once the loader is lowered.