FEL bucket not staying up

[oldnslo]

4570 is correct that with both ports blocked the cylinder cannot retract without an external leak. Reason for this is the difference in volume of the cylinder rod.

A cylinder will extend though without an external leak if the piston seals are bad.

 

[747driver]

Unless you see hydro fluid leaking out, I think you are on the wrong track.
The problem is more likely the loader control (joystick) hydraulic valve or even more likely the control cables or pivot assembly that connect the joystick to the control valves.
The first thing I'd do is look under the rubber boot at the base of the joystick to be sure nothing is broken or disconnected there.
Some of these came with plastic parts and there is a metal upgrade kit. This should show the type of mechanism you'll find at the base of the joystick:
Kioti ck 2 Updated joystick selector assembly - YouTube

Just went out and took the rubber boot off to view the joystick control It is the all metal type. Found nothing broken. Handle is alittle loose so I will tighten that up.

 

[xcgreene]

There was a big debate about that a while back and I used to be of the same belief as you. It痴 impossible for the rod to move back into the cylinders without loosing oil somewhere. If the rod is pulling out of the cylinder loosing oil is a possibility but it could also be bypassing the rod seals.

I see what you're saying now, rod going in, extra rod volume.

 

[747driver]

So I just finished looking at the joystick control. I have the all metal ball type fittings. Found nothing broken. Operated the bucket and everything responds to the joystick command normal. But when you curl the bucket back it immediately free falls forward..... unless you hold the joystick command to curl back in which it will stay up. As soon as you go back to neutral or take pressure off the curl back it free falls forward. Yes, the return line does warm up compared to the pressure line when holding the joystick in the curl up position. Looks like i need to rebuild the cylinders !

 

[747driver]

This is basically the same function as the landing gear struts on commercial aircraft I worked on. Only thing different is aircraft struts have air pressure stored on top of the cylinder filled with hyd fluid. That is whats dampens the shock when you land. So it happens once in awhile the internal seals wear out allowing air to leak down into the hyd section thus causing the strut to go flat. All this with no external hyd leaking. It was always a challenging job taking the cylinder assembly out of the strut and replacing with all new seals !!!

 

[xcgreene]

This is basically the same function as the landing gear struts on commercial aircraft I worked on. Only thing different is aircraft struts have air pressure stored on top of the cylinder filled with hyd fluid. That is whats dampens the shock when you land. So it happens once in awhile the internal seals wear out allowing air to leak down into the hyd section thus causing the strut to go flat. All this with no external hyd leaking. It was always a challenging job taking the cylinder assembly out of the strut and replacing with all new seals !!!

but in the aircraft situation you have that compressible gas. What 4570Man and oldnslo are saying, is that the extra rod volume, when the rod retracts into the cylinder, that rod takes up more space inside the cylinder. meaning less fluid can fit inside the cylinder. Something would have to give. In the aircrafts situation, it was the accumulator. The tractor does not have this

 

[747driver]

but in the aircraft situation you have that compressible gas. What 4570Man and oldnslo are saying, is that the extra rod volume, when the rod retracts into the cylinder, takes up more space inside the cylinder. meaning less fluid can fit inside the cylinder. Something would have to give. In the aircrafts situation, it was the accumulator. The tractor does not have this

My point was that you can have bad seals which leak internally but no external leaks. As you have mentioned the fluid has to go somewhere !!! It just ports it to the dump position through the bad seals. I find my career from commercial aircraft maintenance has helped me immensely..... nice I don't have to sign the logbook anymore saying "Airworthy" !!!

 

[Billrog]

My bucket was doing the same thing I cured the bucket and held it on relief for a min. then felt the top end of the cylinder and took apart the one that was warmest.This is what I found.

Loader only has 1 year warranty but the dealer gave me a new piston end. I suspect this was damaged from new. The bucket is starting to do the same thing on occasion but so far holding the cure on relief isn't heating 1 cylinder more than the other.

 

[xcgreene]

My point was that you can have bad seals which leak internally but no external leaks. As you have mentioned the fluid has to go somewhere !!! It just ports it to the dump position through the bad seals. I find my career from commercial aircraft maintenance has helped me immensely..... nice I don't have to sign the logbook anymore saying "Airworthy" !!!

lol, or having to worry about fod quite as much. I don't have to sign in an out my own tools.

 

[kwbretired]

I might be thinking backwards but the curl cylinders are sucked in in the curl position & push out to dump. If this is the case the oil in the rod end leaking back to the full bore would be less volume therefore allow the bucket to dump with a bad seal.