3-Point Hitch Kubota L1501 3-point linkage

[Gav]

I have a L1501 and the 3 point linkage has begun to struggle to lift. I have a 3' slasher on it and it won't lift while the tractor is idling. By reving the engine, the linkage will lift and hold as per normal.

Now, I assume the hydraulic pump on the side of the engine is the one that runs the linkage (correct??) as the suction runs from the gearbox, to the pump and then the outlet (pressure side) of the pump runs back over to the left hand side of the three point linkage. The tractor has a front end loader on it and the control valve for this is inline of the pipe that runs from the pump to the 3 point linkage. The loader works fine and will labour the engine when the hydraulic cylinders are maxed out, ruling out that the pump is worn and is working correctly.

There is a relief valve on the left side of the 3 point linkage casting under the seat, I have had this apart and all seems to be in order.

So, could it be the seals on the 3 point linkage piston? Does this sound like a possible cause to the problem? Has anyone changed these seals before? Are they a common seal or a special Kubota part?

Any help greatly appreciated.

 

[Gonz]

Is the hydraulic filter blocked?

 

[jesnic]

It might be an obstruction prior to the relief valve. Just remove the relief valve and spring and start the tractor. Fluid should flow out of the relief valve hole and bring with it any debris clogging the valve. Shut down and reinsert valve and start it up. Make sure the valve is not stuck also.