Front End Loader Getting Weak

[xmoto]

I have a Kubota LA481 loader. I bought it used a few months ago. The the lifting cylinders don't see as strong as the should. I will barely pick the front tires off the ground. There are no external leaks. I would like to hear what anyone thinks the problem could be. Thanks

 

[J_J]

Any idea how old? Could be several things. But first, get your self a hydraulic test gage assembly, and check your system out. The test set could be as simply as putting a tee in-line with the pump and screw on the gage, and you are ready to test. The hyd gages are only $ 15 or less from Surplus Hydraulics or Northern, or Baileys.

Now, as far as why, cold be a worn pump. valve leaking, cylinders leaking, relief valve leaking, etc. The gage setup will help you find these troubles.

 

[xmoto]

Thanks J.J. The loader is a 2001. looks like it was used alot / abused. I will check the output psi first.

 

[mark2610d]

I would think the cylinders are probably needing a reseal if it has been used a lot. I have had many hydraulic cylinders rebuilt because the "leaked through" and could not build max pressure thus giving you much less working force. You can rebuild the cylinders yourself with only a few hand tools and a good steady vice to place the cylinder in. The rebuild kits are not very expensive (less than $20.00 most of the time).

Do the cylinders leak down over time if you leave the bucket raised up say overnight? Cylinders that leak down can be a indication of bad seals, (but this is not a 100% way to determine if they are bad). Also, a cylinder does not always leak oil to the outside when they are worn out inside.

Hope this helps,

 

[xmoto]

If the loader is left half way up, in the morning it will be on the ground. Is the dealer the best place to get the rebuild kits?

 

[J_J]

I would think the cylinders are probably needing a reseal if it has been used a lot. I have had many hydraulic cylinders rebuilt because the "leaked through" and could not build max pressure thus giving you much less working force. You can rebuild the cylinders yourself with only a few hand tools and a good steady vice to place the cylinder in. The rebuild kits are not very expensive (less than $20.00 most of the time).

Do the cylinders leak down over time if you leave the bucket raised up say overnight? Cylinders that leak down can be a indication of bad seals, (but this is not a 100% way to determine if they are bad). Also, a cylinder does not always leak oil to the outside when they are worn out inside.

Hope this helps,

A lot of people assume that the cylinders are bad or leaking, but there are other things that will affect the hyd system.

In order to do some logical trouble shooting, one should know the hydraulic pump psi rating. Then as you put the gage further down stream, you will notice where the pressure is not correct. Keep in mind, that there will be no to very little pressure until a lever or switch is activated to make use of the hyd fluid. If you are running a hyd motor, and no load on it, then don't expect to see high pressure. If you put that motor to work cutting grass, the pressure will build up, and could even get to the stall stage, and the motor valve circuit will go into relief. If you have the cylinders extended, and the relief does not activate, that means that you don't have enough pressure in the circuit.

If a hyd pump is worn/weak. you will not be able to do the work it was designed to do. As far as lifting, you may only be able to lift half the limits on your loader. Nothing you test with a worn pump will be correct. 3ph will act like it is working, etc. BH will work , but sluggish, etc.

 

[xmoto]

Do the pumps have data plates for what the output should be?

 

[J_J]

Some pumps do but a lot of manufactures take them off so you will only order from them. You could look up your tractor manufacture, with model, and somewhere in the specs, they will have the psi and GPM. The hyd mechanic in the tractor. shop might be able to tell you, since he has to test them. .

 

[xmoto]

Thanks for the help.