I don't think it matters much how you set the loader down. If you were storing it for a long time I would suggest with the cylinders retracted so the rods aren't exposed but that even isn't likely much of an issue with chromed rods.
FEL bleeding down
- Thread starter TxAg2001
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Raise loader, with or without weight. About a foot off the ground is fine.
Remove the quick couplers from the valve.
Does loader drift back down at same rate? Yes=cylinders have issue (loose piston nuts and/or missing/broken o-ring)? No=control valve internal leak.
Simple diagnosis. That gives you leverage when talking to the dealer.
On changing colors. You trade one problem for another. Trust me....
How much weight are we dealing with here? 1500 lbs? 200 lbs?
A front loader IS a great tool, but it's a "do it all" type tool and a master of none. It works but it's not a dedicated hoist, crane, track-hoe, or whatever and I think sometimes people get the wrong idea.
I will agree though, the rate of drop is excessive and IMO, should be addressed by a dealer. I've not heard of one dropping that much without other complaints (weak lifting, etc). Couple inches per hour, yes-that's normal.
Remove the quick couplers from the valve.
Does loader drift back down at same rate? Yes=cylinders have issue (loose piston nuts and/or missing/broken o-ring)? No=control valve internal leak.
Simple diagnosis. That gives you leverage when talking to the dealer.
On changing colors. You trade one problem for another. Trust me....
How much weight are we dealing with here? 1500 lbs? 200 lbs?
A front loader IS a great tool, but it's a "do it all" type tool and a master of none. It works but it's not a dedicated hoist, crane, track-hoe, or whatever and I think sometimes people get the wrong idea.
I will agree though, the rate of drop is excessive and IMO, should be addressed by a dealer. I've not heard of one dropping that much without other complaints (weak lifting, etc). Couple inches per hour, yes-that's normal.
Most of the work we have been doing lately involves 3" square tubing. A 16' length approximately 85 lbs. raised in the air for overhead gate entrance should not drop an inch in less than a minute.
If the lift cylinder couplers are disconnected and there are NO external leaks, the rod WILL NOT RETRACT on it's own. It is impossible.
Take a glass of water filled to the brim. Now put your finger in it. Does water spill out, yes it does. If you can put your finger in the full glass without spilling any water, then I will accept your statement, but again it will spill because liquid does not compress and to put something (your finger) into the liquid, the liquid gets displaced spilling over the edge.
Well that is what you are trying to do with the rod, but there is no place for the liquid to go because everything is sealed up. The cylinder rod WILL NOT retract on it's own.
Right! If you want to make a single acting cylinder from a double acting one you can simply direct oil to both ends of the cylinder and it will extend. that is how the quick dump works on kubota loaders. ( The cylinder will have the effective area of the rod size)If the lift cylinder couplers are disconnected and there are NO external leaks, the rod WILL NOT RETRACT on it's own. It is impossible.
Take a glass of water filled to the brim. Now put your finger in it. Does water spill out, yes it does. If you can put your finger in the full glass without spilling any water, then I will accept your statement, but again it will spill because liquid does not compress and to put something (your finger) into the liquid, the liquid gets displaced spilling over the edge.
Well that is what you are trying to do with the rod, but there is no place for the liquid to go because everything is sealed up. The cylinder rod WILL NOT retract on it's own.
If you remove the hose from the rod end of the cylinder and oil leaks out of the cylinder you know the piston is leaking ( if oil leaks out of the hose you know it is the other cylinder) . if the loader goes down and no oil comes from the cylinders then the valve or something besides the cylinder is leaking. If the cylinder is loaded in tension then it will move if both hoses are blocked. Most modern loader bucket cylinders are loaded in tension.
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The oil in the cylinder will leak past the piston and the loader will settle. Because the rod displaces a certain volume it will not settle to the bottom but it will settle. It is straight physics and I know from experience.If the lift cylinder couplers are disconnected and there are NO external leaks, the rod WILL NOT RETRACT on it's own. It is impossible.
Take a glass of water filled to the brim. Now put your finger in it. Does water spill out, yes it does. If you can put your finger in the full glass without spilling any water, then I will accept your statement, but again it will spill because liquid does not compress and to put something (your finger) into the liquid, the liquid gets displaced spilling over the edge.
Well that is what you are trying to do with the rod, but there is no place for the liquid to go because everything is sealed up. The cylinder rod WILL NOT retract on it's own.
Well, your experience had some other unknown factors.
As long as there is oil filling both sides of the cylinder at the start of the test, there is NO place for the rod to settle to. And you are right, it is straight physics. The rod settling down into the cylinder displaces oil, so where is that oil going to? NO WHERE with out an external leak. So because there is NO PLACE for the oil to be displaced to, the rod CAN NOT settle into the cylinder.
Like I said, as soon as you can put your finger into a full glass of water and spill no water, then your statement becomes valid, but because of simple physics , that is impossible.
Kubota dealer had the tractor for over 2 weeks. I called during this time and they said they were trying to work with Kubota on a solution. Then I got the call saying it is within Kubotas specs. I was livid and asked "so you're telling me it dropped only 1" in 5 minutes at your place but at my place it drops almost an inch a minute?" I got transferred to service manager...he explained that the 1" is on the cylinder not out at the end of the loader. He said it is because of the valve that they bleed down. My reply was even your salesperson said he hadn't heard of the 5000 series bleeding down, that it is in the 6000 series and that it should only happen when the tractor is off. They offered to come pick it up in a week or so when the Kubota rep was in town. I guess I get to try to convince another person there is an issue.
Well, your experience had some other unknown factors.
As long as there is oil filling both sides of the cylinder at the start of the test, there is NO place for the rod to settle to. And you are right, it is straight physics. The rod settling down into the cylinder displaces oil, so where is that oil going to? NO WHERE with out an external leak. So because there is NO PLACE for the oil to be displaced to, the rod CAN NOT settle into the cylinder.
Like I said, as soon as you can put your finger into a full glass of water and spill no water, then your statement becomes valid, but because of simple physics , that is impossible.
Your theory is sound. HOWEVER....(read on)
Inside the double acting cylinder is a piston, which is bolted to the rod, or as some call it "the ram". That piston has a seal on it. Think of it as a cylinder in a car's engine. It, too, has a seal.
If the seal leaks, the cylinder will leak internally. If, in this case, on a loader-where the lift cylinder is partially extended, and has X amount of weight pushing against it, in this case, say 1000 lbs, and there is leakage (and there will be by design), it's going to leak down over time. The more leakage, the faster the loader falls. If it's only one cylinder, the entire loader will leak down. If it's both, it'll leak down. On Kubotas system, when the loader is "up" (cylinder partially extended), there will be pressure on one side of the cylinders, and only one side. In the control valve, the "down" and "float" side of the spool will be open to the tank port-which leads back to the transmission case. So if the cylinder has an internal leak, some oil will leak past the piston, then return directly back to the transmission. This, is of course with the hoses all attached to the tractor.
If the quick couplers are removed/uncoupled-they still will leak down if there's an internal leak. Experience speaking. That's how we test them at work, and how we were trained by John Deere AND Kubota-way back in the 1980's. Yes there's a bias because of the ram rod but they'll still leak past internally if the seal(s) have an issue, at least to a point where pressure on each side is equal-and in my experience, that does happen but it takes a while. When doing this type test, you don't want to disconnect the quick couplers after letting it sit overnight. Raise loader, shut engine off, remove key, set park brake, get out of tractor and disconnect. Less than 5 min time. IF it's still bleeding down, the cylinders have an internal problem. No bleed down, it's in the valve. It's that simple. I've done it thousands of times and that method is foolproof and simple.
Well if they have another M5 on the lot, ask them to go out and get it-and compare yours to their new one. Betcya there's a big difference. IMO, your bleed rate is excessive.