3PT counter weight causing low hydraulic loader pressure?

[MrZukerman]

A friend of mine bought a used kubota 35 hp tractor with factory loader, can’t recall the model of hand. He has always complained the fuel doesn’t have much lift capacity so took it to a local guy that repairs hydraulic cylinders and stuff to have it looked at and was told the the 1200 lbs or so three point counter weight he is using is taking the biggest part of the available hydraulic pressure to keep raised that the loader doesn’t have enough left over to lift much weight. Anyone else have any experience with this type of issues?

 

[ptsg]

It was important for us to know the exact model so we could know the diagram of the hydraulics.

Usually the loader valve is one of the first valves in the circuit with the remotes and 3 pt valves coming after. So anything after the loader valve, shouldn't really affects how the loader behaves.

Another possibility is a clogged screen or filter in the suction side of the pumps and it's not actually anything to do with the 3 pt.

 

[SPYDERLK]

Typically the 3pt is not using fluid after it has risen to set position. If there is a slow leak in the holding circuit it will leak down a bit and then again use fluid to regain the correct height. Faster leak - more frequent correction. These corrections would affect the fluid available to the loader. .. But there is the possibility of a fast "leak" through the 3pt relief valve because the weight is too heavy to be lifted to the correct position. Does the engine run free and easy when the weight is on the ground, but exhibit constant load when the weight is lifted? This would indicate a problem to investigate.

 

[WranglerX]

"Local Guy" does not know much about hydraulic and 3PH..... One could put stay/check chains on 3PH/Ballast and take load off hydraulics and problem will still exist..... I use use stay/check chains on ballast just to keep it from creeping down so I don't have to worry about ballast when using loader....

 

[MrZukerman]

I was able to ask my buddy what tractor model it is I knew that would be ery beneficial when i first posted but just didn’t remember. It’s a kubota L3300 and LA480 loader.

 

[oldnslo]

I was able to ask my buddy what tractor model it is I knew that would be ery beneficial when i first posted but just didn’t remember. It’s a kubota L3300 and LA480 loader.

If Kubota used a series - parallel type loader valve then trying to lift a load with loader and 3 point simultaneously would limit lift capacity of both. Reason for this is that with series spool on loader the return oil from lift cylinders is directed into the power beyond port feeding the 3 point so any load created by 3 point trying to lift would limit loader lift.

Kubota used this type of valve so can lift load and dump simultaneously or lower and curl. Again not sure if that tractor has this type of valve or not.

Other than that feature a load on 3 point should have zero influence on the loader.

 

[SPYDERLK]

I was able to ask my buddy what tractor model it is I knew that would be ery beneficial when i first posted but just didn’t remember. It’s a kubota L3300 and LA480 loader.

My L's have an adjustable damper valve that can be used to keep the 3ph raised. That should prevent the weight dropping from a possible leak in the height position control system. Check him about any engine loading holding a lifted weight suspended. There should be no apparent loading after the weight reaches set height. If there is, see if lowering it a tad stops the loading. .. Theres an adjustment to correct that issue.