Hydraulic issue

[Ddillard71]

I have cub cadet yanmar sc2400 that I have been dealing with loader lifting issues for a year. I have had at dealer multiple times (cylinder rebuild, leaks fixed, control valve replace) the loader will not lift at all unless high rpms I have tried to explain this to dealer but they cannot get to the problem. Any suggestions would be appreciated but I am at a loss with dealer.

 

[oldnslo]

If this pump externally accessible? If yes does the pump housing get hot when trying to raise the loader compared to the pump inlet line? If pump is failing it will typically get warm pretty fast.

How is this system plumbed. Does the pressure line from the pump go directly to the loader valve or does the pressure connect to block on transmission housing? If transmission housing there might be a plug that is used to direct flow to either loader or three point if loader is not attached. The O-rings on these plugs have been know to fail. test for this would be put an implement on 3 point so there is some load and then attempt to raise 3 point and loader at the same time. Does anything change?

 

[winston1]

Does the curl function operate without high rpm? If so, try swapping curl and lift hoses as a trouble shooting trial.

 

[Ddillard71]

Does the curl function operate without high rpm? If so, try swapping curl and lift hoses as a trouble shooting trial.

No curl unless high rpm

 

[Ddillard71]

If this pump externally accessible? If yes does the pump housing get hot when trying to raise the loader compared to the pump inlet line? If pump is failing it will typically get warm pretty fast.

How is this system plumbed. Does the pressure line from the pump go directly to the loader valve or does the pressure connect to block on transmission housing? If transmission housing there might be a plug that is used to direct flow to either loader or three point if loader is not attached. The O-rings on these plugs have been know to fail. test for this would be put an implement on 3 point so there is some load and then attempt to raise 3 point and loader at the same time. Does anything change?

If this pump externally accessible? If yes does the pump housing get hot when trying to raise the loader compared to the pump inlet line? If pump is failing it will typically get warm pretty fast.

How is this system plumbed. Does the pressure line from the pump go directly to the loader valve or does the pressure connect to block on transmission housing? If transmission housing there might be a plug that is used to direct flow to either loader or three point if loader is not attached. The O-rings on these plugs have been know to fail. test for this would be put an implement on 3 point so there is some load and then attempt to raise 3 point and loader at the same time. Does anything change?

Will not lift either at same time without high rpm. Had pump replaced a year ago never has been same before I started having problems

 

[Ddillard71]

Will not lift either at same time without high rpm. Had pump replaced a year ago never has been same before I started having problems

 

[winston1]

Does it seem the pump is under load anytime working controls? If you have quick disconnects in your system have you looked at them closely assuring nothing wrong with them and fully plugged in?

 

[oldnslo]

Dilliard
If pump and valves have been replaced time to get down to basics. Either pump is not getting oil or there is a significant leak in the circuit.

No oil to pump:
Has the inlet or pump suction screen been inspected or cleaned?
All suction lines and hoses inspected for cracks, hose clamps tight, fittings tight, etc.

I mentioned simple pump test in post #2. If this is not possible then on to system leak tests.

System leak:
This one is a little harder since it requires equipment to flow and pressure test. You need to isolate the pump from valves to verify if pumping oil and then to watch flow as pressure is increased. If pump passes you then need to check next component in the circuit until problem is found.

 

[Ddillard71]

Does it seem the pump is under load anytime working controls? If you have quick disconnects in your system have you looked at them closely assuring nothing wrong with them and fully plugged in?

Quick disconnects all good, new couplers. Only time seems under load 3pt lifted all way up. Called dealer, yanmar says pressure within specs, dealer says we can try new pump, yanmar says it will not matter. Never had this problem until year ago had pump replaced and no difference. So this will be 2 pumps in one year.

 

[Ddillard71]

Dilliard
If pump and valves have been replaced time to get down to basics. Either pump is not getting oil or there is a significant leak in the circuit.

No oil to pump:
Has the inlet or pump suction screen been inspected or cleaned?
All suction lines and hoses inspected for cracks, hose clamps tight, fittings tight, etc.

I mentioned simple pump test in post #2. If this is not possible then on to system leak tests.

System leak:
This one is a little harder since it requires equipment to flow and pressure test. You need to isolate the pump from valves to verify if pumping oil and then to watch flow as pressure is increased. If pump passes you then need to check next component in the circuit until problem is found.

Dilliard
If pump and valves have been replaced time to get down to basics. Either pump is not getting oil or there is a significant leak in the circuit.

No oil to pump:
Has the inlet or pump suction screen been inspected or cleaned?
All suction lines and hoses inspected for cracks, hose clamps tight, fittings tight, etc.

I mentioned simple pump test in post #2. If this is not possible then on to system leak tests.

System leak:
This one is a little harder since it requires equipment to flow and pressure test. You need to isolate the pump from valves to verify if pumping oil and then to watch flow as pressure is increased. If pump passes you then need to check next component in the circuit until problem is found.

 

[Ddillard71]

All leaks fixed, pressure test within specs on low side, dealer says we can try another pump

 

[wdchyd]

Dealer should be doing a flow/load test on the pump. Pressure gauge only is not a complete test. Pressure alone with a no flow condition doesn’t move a load.
The proper pump test would only take a few minutes with no guess work. If it’s good then move on to another component.
“Dealer says we can try another pump” sounds like guessing.

 

[winston1]

Probably already been mentioned but do you have the correct micron filter in place? If not, suction could be compromised.

 

[ptsg]

Ddillard71, I would do this simple test, even at a idle. Pull back the loader joystick to lift and hold back the remote lever if you have one, or try lift the 3 pt at the same time. This will let us know if you have two of the lines reversed or if there is an issue with the o-ring on the Power Beyond fitting.

 

[setxjeff]

Do not discount the quick disconnects, I bought 4 sets and 3 of the 4 were bad. Drove me crazy for a few weeks till I took all quick connects out of the system and directly screwed the fittings together and slowly replaced the quick connects one set at a time.