2020 Kubota SVL75-2 Skid loader will not lift arms or curl under load without RPM at least 50% up. Works fair at full RPM but slow. Want to know how to diagnose if it is the pump or in the control valve assembly. Could it be the spool's for the curl and lift or the relief cartridges? How do I test to find out? They both went weak at the same time. Even at high idle you cannot lift the arms and curl at the same time it does not have enough power. The highflow is also weak on power for my mulching head. This leads me to think it is the high flow pump but there is only 1200 hours on this machine. There are no unusual sounds from the pump. With empty grapple bucket on - When at idle in loader and I curl the bucket very slow you can hear the hydraulic flow. When actuating the lift arms it will be silent and they will move an inch or so and stop. you hear the flow as usual when lowering. The power from the track pumps is great. Only issue on high flow pump side. I also assume these pumps cannot be rebuilt? Any advice would be appreciated. Thank you Toby White
To know for certain without pulling anything, you will need to get a flow meter with a needle valve and gauge installed in the pressure line from the pump to the control valve. Can you hear the ‘scream’ when you dead-head the cylinders? Do you have more power when the machine is cold? Higher engine RPM means more flow from the gear pump. More flow can compensate for internal leakage (from a faulty pump or relief valve) and cause it to work better. I would bet on the pump, but it could be the main relief in the control valve. Do you have the numbers from the gear pump?
Hey Toby, Did you ever find the issue with your loader? Mine is doing the same thing and it only has 100hr.
Hey Toby, where did you go or what fixed it? I have the same issue on a SVL75-2 with 800hrs. Tracks run fine and have power but boom and bucket are super slow even at mid throttle. Idle they can’t be raised. Any ideas?
Wish there were a way that folks could mark the solution for the issue they faced on this site!!! On this machine, we tested the flow and output pressure with a flow meter and resulted in almost zero flow at 2k psi. or even worse at idle. This is well below what it should be - spec would say something around 2750 -3750 psi pressure relief and flow around 15 gpm at idle or low throttle. so, RESULT? BAD PUMP, - tore it down - simple enough and the pump was shelled out completely on the bushings on one end and gears had major wear and flaking. Pump housing was gone! Cleaned the entire hydraulic oil tank and BOTH in tank filters- a must! Changed after pump hydro filter and flushed system Runs like new! Shop pumps from Kubota or PM us for cheaper options that are still OEM pumps SOLVED!
Great news you got it fixed...but pump gone at 1200h. Wow; that seems very surprising. Do you have any idea why the pump would fail at such low hours? Mulching is high demand no doubt....too much heat in the system?