Quickie loader, very slow. WHY?

[oldnslo]

Jahmes
Did you give up on purchasing the flow meter and required hose and fittings?

 

[rScotty]

OK. It certainly is difficult to diagnose this problem remotely. My feeling is that it is not a part failure or we would have found it by now. That means it may well be a misconnection or control that we've not found - perhaps it was always so, since it does work...although slowly.

My guess is that we are missing an adjustment or connection back at the ports designated as accessory hydraulic connections which sit to the right side of the rockshaft casting. There pors are standard equipment on all this series of M Kubotas and are the obvious place to access hydraulic flow for the loader.
The WSM has a short section with a flow schematic that addresses the adjustment of these ports. It is out of sequence, being an addendum on the very last page of the WSM.

The more I study these 1995-2005 M4700 thru M6900 Kubotas, the more impressed I am with the way they are designed.

Choose your dealer mechanic carefully. And let us know what the resolution is.
& Thanks,
rScotty

 

[jahmes143]

@oldnslo I purchased the flowmeter and fittings, waiting for them to arrive. That could tell us something. I also messaged Alo and asked if they had any literature specific to this loader and control valve. Will report back on any developments!

@rScotty we also have an M5640SUD, bought new and now has ~2500hrs and we have been very impressed with it.

 

[jahmes143]

Was able to come across the manual for my valve (part 521641). See pages 41 and 42 where it appears to show 3 different configuration options.

 

[rScotty]

Was able to come across the manual for my valve (part 521641). See pages 41 and 42 where it appears to show 3 different configuration options.

Those 3 schematics on page 41 look the same to me except for the relief valve settings. Whatever difference in flow that those inset schematics are trying to show....well, I don't see it. Maybe I'm just missing it....or maybe they are referring to working cylinder geometry and not showing the "obvious" cylinder orientations. But if so, why make up schematics when a simple note would suffice?
mystified,
rScotty

 

[jahmes143]

Update...I got a flow meter and am getting 7-8gpm at 2000rpm and fluid at about 60 degrees. I believe pump is rated up to 11gpm but not sure what RPM that would be at. I will let the tractor warm up and re-test in a few days. Didn't have much time tonight.

This was tested by placing the flow meter in line, with the supply hose on one side (hose #1 in my prior pics) and the control valve on the other side.

 

[oldnslo]

Great job on getting the flow meter installed.

7 - 8 GPM should operate that loader at a reasonable speed. If pump is original to the tractor the flow of 11 GPM would typically be at rated PTO RPM or close to full throttle.

Going from memory without going back and reading all pages on this post I believe there was a block of some sort between the pump and loader valve. Is this block now between the flow meter and the loader valve? If yes is there anyway to move the flow meter in line between that block and loader valve? That would verify the flow is getting to the loader valve or not.

 

[jahmes143]

Great job on getting the flow meter installed.

7 - 8 GPM should operate that loader at a reasonable speed. If pump is original to the tractor the flow of 11 GPM would typically be at rated PTO RPM or close to full throttle.

Going from memory without going back and reading all pages on this post I believe there was a block of some sort between the pump and loader valve. Is this block now between the flow meter and the loader valve? If yes is there anyway to move the flow meter in line between that block and loader valve? That would verify the flow is getting to the loader valve or not.

Not sure what block you're referring to. Maybe that was a different thread? A top potential issue of mine was air getting in the lines. I replaced all O-rings on suction side and that didn't resolve the issue. I also confirmed pressures were within spec, and most recently confirmed flow to loader valve is acceptable. Maybe I need to try a new valve.

 

[oldnslo]

Not sure what block you're referring to. Maybe that was a different thread? A top potential issue of mine was air getting in the lines. I replaced all O-rings on suction side and that didn't resolve the issue. I also confirmed pressures were within spec, and most recently confirmed flow to loader valve is acceptable. Maybe I need to try a new valve.

Sorry on getting posts confused but if you have both flow and pressure going into the valve we next need to figure out where it is going.

Can you move the flowmeter to the power beyond line? I believe that line 3 in picture of the valve. When trying to raise at full speed do you see any flow? Same with curl or dump and full command?

If yes does the volume of flow change when cylinder hits end of stroke?

 

[jahmes143]

@oldnslo this tractor does not have power beyond. Post #27 shows hose 3 goes from the control valve to the rockshaft. I can still place the flow meter in line here and test if helpful.