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.