Zebrafive
Super Member
OP have you check pressure of the tractor's hydraulics and compared them to factory specs? That will tell you if hydraulics is getting weak.
Possible weak loader or just too much weight?
- Thread starter bazman82
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CobyRupert
Super Member
Do you know if it's too much for the loader or too much for the tractor's hydraulic system?
The capacity of an FEL's is dependent on what PSI the tractor is supplying.
Maybe invest in a hydraulic pressure gauge so you can see what the tractor is supplying to the loader.
If spears don't curl at normal operating pressure, I think the pressure will build until 1 of 3 things happens: Hydraulic cylinder moves, tractor's hydraulic system goes into relief, or cylinder's seals get blown out.
Looking at FEL spec's they list ratings at different tractor hydraulic pressures, but I don't see where they have a maximum pressure rating. https://www.woodsequipment.com/files/Products/Manuals/MAN0554.pdf
When it doesn't curl, can you hear the engine load or tell if the hydraulic system is going into relief?
The capacity of an FEL's is dependent on what PSI the tractor is supplying.
Maybe invest in a hydraulic pressure gauge so you can see what the tractor is supplying to the loader.
If spears don't curl at normal operating pressure, I think the pressure will build until 1 of 3 things happens: Hydraulic cylinder moves, tractor's hydraulic system goes into relief, or cylinder's seals get blown out.
Looking at FEL spec's they list ratings at different tractor hydraulic pressures, but I don't see where they have a maximum pressure rating. https://www.woodsequipment.com/files/Products/Manuals/MAN0554.pdf
When it doesn't curl, can you hear the engine load or tell if the hydraulic system is going into relief?
k0ua
Epic Contributor
Remember guys, hydraulic pumps on an open center system don't make pressure. They make flow. Pressure develops when that hydraulic flow meets resistance. A hydraulic pump makes the same pressure at idle as it does at high speed, which is to say none. Now all hydraulic valves leak. Just how much they leak varies. When you get that little more lift ability by increasing RPM is the fact that you have increased the flow rate so that now more pressure can be developed to overcome the leakages in the system. The rate that the load can be lifted is of course much more at high speed than at idle. One more time. The hydraulic pumps on our tractors don't make pressure, never have and never will.
Back to the original posters "problem". Of course the relief valve is going into relief and fluid is now flowing over the relief valve and back to tank when he tries to curl that excessive (for relief valve setting) load out on the end of his bale spear. Now the question: is this normal operation or is this a defect? Well without the specifications and a pressure gauge we do not know. If I was to hazard a WAG I would say that a 30 to 40 year old tractor has a very good possibility that the relief valve spring is likely weaker than when it was new and the control valves leak more fluid past them also. It would not take a whole lot of effort and money to replace the pressure relief spring or shim it.
Back to the original posters "problem". Of course the relief valve is going into relief and fluid is now flowing over the relief valve and back to tank when he tries to curl that excessive (for relief valve setting) load out on the end of his bale spear. Now the question: is this normal operation or is this a defect? Well without the specifications and a pressure gauge we do not know. If I was to hazard a WAG I would say that a 30 to 40 year old tractor has a very good possibility that the relief valve spring is likely weaker than when it was new and the control valves leak more fluid past them also. It would not take a whole lot of effort and money to replace the pressure relief spring or shim it.
k0ua
Epic Contributor
Yup....
OP
bazman82
Gold Member
I will have to get a pressure gauge to check. I may know someone I can borrow one from. As for a relief noise when it tries to curl, I don't recall there being any noise when I have tried to curl but I could be wrong, I'm usually thinking about a million other things I need to do. I do however get the relief noise when I curl the bucket back all the way to its stopping point. I will be moving some round bales this weekend, I will try to get a video of what it does when I try to curl it with the bale spear partial in and fully in.
OP
bazman82
Gold Member
I should also mention that the loader plugs into my only 2 ports I have in the rear of the tractor. Not sure if that makes a difference or not.
k0ua
Epic Contributor
By definition something is going into relief. Either the relief valve, which is the most likely scenario, or the pump is so worn that the fluid is escaping internally, not a likely scenario but possible or the control valves or cylinder leakage, also not all that likely but possible.
When you try to pickup a load and the cylinder stops movement, something has to happen. either the relief valve opens, the pump "grenades" and explodes, or a hose blows, or engine stalls, something HAS to happen.
Richard
Elite Member
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This is getting my vote. I've got an industrial loader/backhoe. I think lifting force is something like 6,000 lbs (don't recall).
Was moving some boulders and found one "about the same size as the others" BUT, it was shorter and stuck out further since I couldn't fit it into my bucket.
Was all I could do to lift that boulder. Was so bad, I was extending my backhoe out the back to get some weight leverage back there. I was at times, teetering on the front wheels until I did that. Then, I had to use my steering brakes to help turn.
It wasn't really a monster of a boulder (though it was large), it was a pancake boulder and a good portion of it stuck way out the front, giving me some fits.
KYErik
Platinum Member
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I assume your curl cylinders retract to curl the spear upward? My JD loader is designed the same way and it really limits how much curl pressure it has. I have an issue curling tight large round bales (5 X 6).
My old Case 530 loader has a linkage that curls the bucket when the cylinders extend- a much better system with more power (there are more square inches of surface area on the flat side of the hydraulic cylinder piston than there are on the rod side of the cylinder piston). I suppose most loader manufacturers use retracting cylinders to curl the bucket upward because there are fewer moving parts. If I ever purchase another loader, it will be one that uses extending cylinders to curl the bucket upward.
My old Case 530 loader has a linkage that curls the bucket when the cylinders extend- a much better system with more power (there are more square inches of surface area on the flat side of the hydraulic cylinder piston than there are on the rod side of the cylinder piston). I suppose most loader manufacturers use retracting cylinders to curl the bucket upward because there are fewer moving parts. If I ever purchase another loader, it will be one that uses extending cylinders to curl the bucket upward.
k0ua
Epic Contributor
He brings up a very good point about the forces available when curling vs. the forces available when dumping. Curling is the weakest force because of the rod being in the cylinder and less surface area for the fluid to push against.
