FEL problem

[hamestring]

I have a Kubota M8200 with a Bush Hog M446 FEL. It has developed problem lately. When I attempt to lift a load it won't lift unless I rev the engine up to about 1500 rpm. Fluid level is ok. It doesn't leak down when I cut it off but it will actually drop when I move the joystick down at idle. Bucket tilts fine. Any ideas?

 

[Eric McCarthy]

When was the last time the fluid and filter was changed?

 

[KenB2920]

No idea but off the top of my head i would try simple trouble shooting:

Filter being number #1

Fluid level, disconnect your quick connects and reattach them, then check and recheck the filter. Check for any loose connections or leaks.

 

[seanbarr]

It doesn't leak down when I cut it off but it will actually drop when I move the joystick down at idle. Bucket tilts fine.

You mean when you attempt to make the loader arms go up by pulling down on the joystick, it goes down? If that's the case, sounds like your controller needs to be looked at. Perhaps a seal rebuild kit is in order?

 

[hamestring]

I've checked the quick connects, fluid level is good, took out the relief valve, felt for heat on relief valve and cylinders. No obvious problems. I've swapped the lines from the tilt cylinders and the lift cylinders and there was no difference (except every thing worked backwards). It doesn't go down as in pushing down but fails to hold up or lift up when idling. When it's not running the loader holds up fine if I push the joystick down but why would it drop when the engine is running at idle? Haven't changed the filters lately but the oil is so clean you can barely see it on the dipstick.

 

[seanbarr]

So with the connections reversed, the problem remains the same as if it wasn't reversed or did it "follow the hoses"? Did the problem now shift to the bucket tilt (side to side action of the controller) or still remain with the lift (forward-back action of the controller)?

In other words, if the bucket now acts screwy when you swapped the connections, I suspect the controller.

 

[Stubbyie]

Consider changing filter(s) first as may be restricted. If you have doubts how long it's been then the filters need changing anyway.

Next is one or more shot O-rings in hydraulic hand control feeding FEL.

 

[hamestring]

Problem remained the same when hoses were swapped which makes me think it's not the control valve. I suspect it's a cylinder problem but don't know how to be sure.

 

[seanbarr]

Wait a minute, It's your pump! It's likely leaking pass the seals. Makes sense now because when you operate the controls to divert pump pressure to the arms, the cylinder side has more pressure than the pump can produce at low idle and it would just flow backwards. With the controls at neutral, it just cuts off the cylinders from back-flowing.

Kicking myself for not catching it in the first place...

 

[hamestring]

I hope you're wrong seanbarr! That sounds expensive. I bought filters today and will change them tomorrow. If that doesn't fix it I'll get a gage to check the hydraulic pressure. Anybody know what it should be? Should it vary at different rpm's?