Replacing hydro pump--what else do to while there?

[GS650GL]

There are no detents on either of my 3-point levers, and no mention in the owners manual of setting the green draft control lever to any particular setting if you're not using draft control. When I'm just driving around, the blue 3-point lever generally has the arms raised somewhere in the top half, but rarely pegged all the way up.

I'm not sure what you mean by "deadheading." Can you elaborate?

To accurately diagnose a hydraulic issue you need to measure both flow and pressure, not just one or the other. A pump can put out enough flow under low or no pressure to make it look like it's OK, but when you start building pressure with the oil at operating temp, the flow should not drop by more than 10% at 1500 psi. Example: if a pump puts out 10 gpm at specified rpm under no pressure, it should not drop below 9 gpm at 1500 psi. If it drops more than 10%, the pump is worn and bypassing oil internally. How did they measure the flow? A diagnostic flowmeter has a load knob that can be turned to gradually build pressure so if they used one to check flow, they should have been able to check pressure also. If the knob is turned to the point where flow almost stops, thats's the relief valve opening pressure. I think your relief valve should be set to 2400 PSI. A bad or misadjusted relief valve is not affected by oil temp and the pressure will be always low. A restricted filter may cause the hydraulics to be slower, but will still have the same power (unless it's plugged and starving the pump, of course) A worn pump will work better when cold and lose pressure when hot, which sounds like the problem you are having. All loaders will slowly settle downward over time, but does it settle faster or worse when the oil is hot? If so, the boom cylinders could be bypassing oil internally.

There are no detents on either of my 3-point levers, and no mention in the owners manual of setting the green draft control lever to any particular setting if you're not using draft control. When I'm just driving around, the blue 3-point lever generally has the arms raised somewhere in the top half, but rarely pegged all the way up.

I'm not sure what you mean by "deadheading." Can you elaborate?

When I mentioned detents, I was referring to the rear remote control levers for the couplers on the back where you can plug in hydraulic hoses, not the 3 point hitch levers. Deadheading means the pump is at max pressure but the oil cant't flow anywhere which blows the relief valve which affects the performance of all functions, and overheats the oil. A remote lever not in neutral or the hitch at max height and not cancelling (still trying to raise) will cause it. If you lower the hitch all the way down, will it raise back up and cancel before it hits the upper limit? How hot is the oil getting? Inside the transmission it should not get hotter than 100 degrees F above ambient air temp. Make sure the oil cooler and radiator are not plugged with dirt. I hate to say it, but unfortunately, there's usually a reason someone sells at an auction to get rid of a machine several states away.

 

[oldnslo]

@oldnslo Do this with a laser thermometer, I assume? I've always wanted an excuse to go buy one. Should I do this at idle speed, or does it matter?

The owner's manual says the hydraulic system is rated at 8.2 gpm. The dealer measured both the old & new pumps at just 6 gpm. Is this a difference in where the flow is measured? A 25% reduction in rated flow concerns me. They claim to have replaced the pump with a 12cc model, which I know is the proper size.

A laser thermometer would be best but if components are accessible your hand would work.

Is the 8.2 GPM the combined flow of both steering and implement?
Example: 2.2 GPM is steering and 6 GPM is for implements.

 

[Obi-Wan-YJ]

A laser thermometer would be best but if components are accessible your hand would work.

Is the 8.2 GPM the combined flow of both steering and implement?
Example: 2.2 GPM is steering and 6 GPM is for implements.

The manual says 8.2 gpm for the pump and 4.1 gpm for the steering. The 6 gpm measured by the shop is somewhere in between, so I'm not sure where they measured it.

 

[oldnslo]

For reference:
A 12 cc pump spinning at 2600 RPM = 31.2 liters/min or 8.25 GPM at 100% efficient.

If only seeing 6 GPM I would be asking dealer the question where is the rest of the flow from that new pump?
Like GS650 asks it Would also be nice to know what flow does vs pressure since that is the real diagnosis for a failing pump with ALL other components removed from the system. I.e. flow meter is first thing from the pump to insure no flow loss through any other component before the flow meter.

I wish you the best in getting this problem resolved.

 

[GS650GL]

It's important that they measured the flow correctly or the numbers are misleading. Like oldnslo said, the flowmeter needs to be hooked directly to the pump outlet, not somewhere downstream, and the outlet of the flowmeter should go directly back to reservoir and not through any other plumbing because the return could have some restriction and back pressure that could affect the test results. But it's important to remember that with the flowmeter hooked directly to the pump, the relief valve is no longer in the circuit and if too much pressure is built by the flowmeter load control, the pump can split apart. I've seen it happen.

 

[Obi-Wan-YJ]

In case you all hadn't figured this out, I'm rather new to using a loader (18 months) and had never stressed its capacity until this month.

@GS650GL I double checked the rear levers. One is a momentary lever, which of course springs back to center. The other one was, indeed, pushed all the way to one end. That's how I got it back from the dealer, and may well have been how I gave it too them. I moved it back to the center detent and will be careful to keep an eye on it going forward.

So I went out today to see how many 1-ton pallets of bricks I could move before my tractor gave up. This time, I raised my engine rpm beyond the middling range up to about 2300 rpm. (PTO speed is 2400) To my surprise, I was able to move all 15 of the remaining pallets--9 of them one right after the other--and the tractor never complained. This was with the pallet pushed all the way back against the forks mount, the tips raised up as high as they would go (not very far), and the back of the pallet raised about 6" above ground. I moved them about 50 yards. I had one pallet that weighed 2500 lbs, and while I could roll the fork tips up, I could not raise that pallet off the ground without offloading some weight.

My loader is rated at 2713 lbs at the pin at full height and 3802 lbs breakout force. The pin is 67" from the main pivot at the back of the loader arms. The forks+bricks weigh a combined 2350 lbs with a center of gravity 26" beyond the pin, or 93" from the main loader arm pivot (40% farther out than the pin). A little math says that 2317 lbs at the pin equates to 1954 lbs at my load's center of gravity. This means I was able to comfortably lift 400 lbs more than the loader is specked for. The one heavier pallet (at a longer distance from the pivot) that I could not lift would have been about 1000 lbs beyond spec. Am I figuring that right when I assume that the lift capacity is reduced proportionally as the load moves farther out from the pin? If I'm calculating things correctly, then it appears that my loader is now operating just fine now that I'm learning more about how to run it.

I'm still a little fuzzy on how the 3800-lb breakout force differs from simply lifting something a couple inches off the ground. Is that an entirely different mechanical operation?

I'm very curious to see how much my 3-point can lift for a sustained time with the new pump. This spring, I borrowed a PTO tiller, and after an hour of use at PTO rpm (2400), I was unable to lift the tiller off the ground. I'm considering buying a 3-pt frame for my forks, since the 3-pt is rated for 2469 lbs at 24" behind the links.

I wish I could answer some questions about how the dealer did some of their testing. Alas, every single employee there that I spoke with has sounded... less than competent, so I think pursuing those answers is a lost cause. I will be buying a laser thermometer tomorrow and a hydraulic pressure gauge soon. My tractor does not have an OEM hydraulic fluid temperature gauge.

 

[Obi-Wan-YJ]

Upon further consideration, the geometry of the lift cylinders with respect to the loader arms also affects the lift capacity, so there's more to it than just the load's distance beyond the pin. The cylinder geometry has better leverage when the load is near the ground than when the load is at full height, and it's that full height capacity that is published. I could do that math, too, if I felt like it, but I don't at midnight. Suffice to say that I'm probably not exceeding the rated lift capacity like I suggested in my previous post.

 

[oldnslo]

Upon further consideration, the geometry of the lift cylinders with respect to the loader arms also affects the lift capacity, so there's more to it than just the load's distance beyond the pin. The cylinder geometry has better leverage when the load is near the ground than when the load is at full height, and it's that full height capacity that is published. I could do that math, too, if I felt like it, but I don't at midnight. Suffice to say that I'm probably not exceeding the rated lift capacity like I suggested in my previous post.

Sounds like problem is resolved. Since pressure is lifting force you might want to invest in a pressure gauge to verify what the system pressure - relief setting is. Then you will know if getting full rated lift capacity.