LA504 Loader

[kickit]

I have a Kabota B3300 tractor with the LA504 loader which periodically and for no reason will only lift about 18” from ground level. After a minute or two of working the lift lever it finally returns to normal operation. I have disconnected, reconnected the hydraulic quick connect fittings, worked with the lift lock and any other possible solutions I can think of with no resolution. Has anyone experienced this problem?

 

[Jstpssng]

No doubt you have checked the fluid levels and filters so it sounds like you have air in the system. Have you done any work on it recently, and/or fixed any major leaks?

 

[loggin]

I have a Kabota B3300 tractor with the LA504 loader which periodically and for no reason will only lift about 18” from ground level. After a minute or two of working the lift lever it finally returns to normal operation. I have disconnected, reconnected the hydraulic quick connect fittings, worked with the lift lock and any other possible solutions I can think of with no resolution. Has anyone experienced this problem?

How many hours on the machine?
When was the last hydraulic fluid and filter change?
Have you checked the linkage for proper operation?
Does the fluid look foamy or milky?

 

[rScotty]

Since the LA504 has quick change connectors on hoses between the loader and the control valve, I would swap the positions of the bucket and lift cylinders. That would tell you if the problem is in the cylinders/hoses, or in the FEL control valve.

 

[oldnslo]

When it stops lifting do you hear the tractor straining like cylinders are at end of stroke? If yes I would suspect one of the quick disconnects is starting to fail acting like a check valve. The cure if that is true is replacing the quick disconnects

 

[kickit]

How many hours on the machine?
When was the last hydraulic fluid and filter change?
Have you checked the linkage for proper operation?
Does the fluid look foamy or milky?

350 hrs on tractor, changed fluid and filter at 50 hrs. Linkage is good and oil is not foamy or milky. Thanks!

 

[kickit]

When it stops lifting do you hear the tractor straining like cylinders are at end of stroke? If yes I would suspect one of the quick disconnects is starting to fail acting like a check valve. The cure if that is true is replacing the quick disconnects

No strain but might replace them if problem persists. Thanks!

 

[kickit]

No doubt you have checked the fluid levels and filters so it sounds like you have air in the system. Have you done any work on it recently, and/or fixed any major leaks?

No work has been done I’ve only removed loader once and that was probably ten years ago. The problem has only been happening roughly a year. Thanks!

 

[Jstpssng]

No work has been done I’ve only removed loader once and that was probably ten years ago. The problem has only been happening roughly a year. Thanks!

If it's been going on for a year I would be a bit more diligent about learning what is going on. Try changing your fluids first. Have you noticed anything in the way that it drives? Hydrostatic uses the same fluid to operate the transmission as the loader.

 

[Harry in Ky]

This only affects one function? Loader lift only? Not bucket curl or loader boom down (as in lifting the front of the tractor)?

If so, changing fluids and/or filters is is a waste of time and money. It's not a fluid problem. Couplers? Maybe, but only you can see, hear, and feel what's happening when this occurs. All you get from out here are guesses. If it were me, I would swap the couplers (not just uncouple and move them around, but actually unscrew all four and trade places) from lift spool to the bucket spool and see what happens. No cost, and if it doesn't help you haven't hurt anything.

 

[kickit]

This only affects one function? Loader lift only? Not bucket curl or loader boom down (as in lifting the front of the tractor)?

If so, changing fluids and/or filters is is a waste of time and money. It's not a fluid problem. Couplers? Maybe, but only you can see, hear, and feel what's happening when this occurs. All you get from out here are guesses. If it were me, I would swap the couplers (not just uncouple and move them around, but actually unscrew all four and trade places) from lift spool to the bucket spool and see what happens. No cost, and if it doesn't help you haven't

If it's been going on for a year I would be a bit more diligent about learning what is going on. Try changing your fluids first. Have you noticed anything in the way that it drives? Hydrostatic uses the same fluid to operate the transmission as the loader.

Thanks! No nothing else is effected, drives fine, 3-point works fine and bucket rolls as it s should.

If it's been going on for a year I would be a bit more diligent about learning what is going on. Try changing your fluids first. Have you noticed anything in the way that it drives? Hydrostatic uses the same fluid to operate the transmission as the loader.

This only affects one function? Loader lift only? Not bucket curl or loader boom down (as in lifting the front of the tractor)?

If so, changing fluids and/or filters is is a waste of time and money. It's not a fluid problem. Couplers? Maybe, but only you can see, hear, and feel what's happening when this occurs. All you get from out here are guesses. If it were me, I would swap the couplers (not just uncouple and move them around, but actually unscrew all four and trade places) from lift spool to the bucket spool and see what happens. No cost, and if it doesn't help you haven't hurt anything.

Thanks Harry, I will definitely try this because only the lift is effected all other functions perform as they should. My son has the tractor now but I will do this once he returns it. Fingers crossed!

 

[Harry in Ky]

Just a note. I suggested swapping all four couplers. My mistake there, as you actually have eight parts involved. The male ends can be defective as well.

 

[Fxfymn413]

It could also be a failed seal in one of the hydraulic cylinders allowing fluid to flow past the seal to the drain side of the cylinder.

 

[kickit]

It could also be a failed seal in one of the hydraulic cylinders allowing fluid to flow past the seal to the drain side of the cylinder.

Thanks!

 

[Redlined0002]

Either the loader joystick linkage or it is inside the loader control valve

 

[kickit]

Linkage appears to be fine so yes possibly the valve bypassing. Thanks!

 

[LD1]

One more thing to try.

It could be the 3ph feedback slightly out of adjustment.

Sometimes when raising the 3ph all the way.....it goes to its max height.....but is STILL trying to go higher because of slight feedback adjustment issue. If that happens....you can usually hear the tractor labor a bit. Like it labors when raising an implement but never "relaxes" when it goes all the way up and stops. But it takes a keen ear to hear it.

So try this.....if it happens again.....and your loader is stuck....try slightly bumping the 3ph lever down just a bit

 

[5030]

I believe I'd lubricate the joystick linkage before anything else. It does require lubricant to work correctly.

 

[bgr]

One simple check you could make is to disconnect all quick connect connectors, check each for dirt or any problem and reconnect. A connector which is attached but not fully latched can restrict flow. A not fully latched connector is not obvious to see, so the best check is to take apart and reconnect.
Be sure to do it with engine off, loader on the ground, and all pressure relieved.(Move joystick around with engine off and loader on the ground.)

LD1's post about 3ph lever problem is also something to check.

 

[kickit]

One more thing to try.

It could be the 3ph feedback slightly out of adjustment.

Sometimes when raising the 3ph all the way.....it goes to its max height.....but is STILL trying to go higher because of slight feedback adjustment issue. If that happens....you can usually hear the tractor labor a bit. Like it labors when raising an implement but never "relaxes" when it goes all the way up and stops. But it takes a keen ear to hear it.

So try this.....if it happens again.....and your loader is stuck....try slightly bumping the 3ph lever down just a bit

I will try that…Thanks!