Loader sticks in raise position

[Notforhire]

Most of the time my JD 553 loader works in a normal manner.

Sometimes it will stick in a slow raise position.
I found two ways that I can make it stick.

(1) Put a load in the bucket, and while lowering the loader arms, stop abruptly. Now if I raise the bucket slowly, I can remove my hand from the stick and the arms will continue to go up.

(2) I fully dump the bucket and hold it in the dump position for a second, allowing the hydraulics to bypass. Raise the loader arms, and they will continue with my hand off the stick.

Each time when the handle is returned to it's neutral position, it feels like it had been in a detent.

The loader controls are cable operated, but I don't think anything is wrong there. While operating other than mentioned above, the control handle returns without issue.

I think the problem is in the valve itself.
The loader has done this from day one, I just could never figure out how to duplicate it until now.

Does anyone have an explanation as to what would cause this to happen?

Thanks, Bill

 

[oldnslo]

Bill,
Can you see the ends of the spools where the cables connect on your valve. If yes when you go into the slow lift mode can you tell if they are centered the same as when the loader is not moving?

What I suspect is happening is that your valve is getting in a position where flow forces are holding the valve just slightly open and it may take a little force to get the valve back to center. Flow forces usually try and close a valve but if the movement is slow it can cause them to stick slightly open. Not a common occurrence but it does happen.

If you move the the joystick to raise faster and then stop does the loader now stop moving? I suspect it will but just curious to see if it does or not.

 

[Notforhire]

Thank you for the response. I need to move a few tons of sand tomorrow afternoon, and I'll try to pay close attention so I can answer your questions.

Best, Bill

 

[Notforhire]

Can you see the ends of the spools where the cables connect on your valve. If yes when you go into the slow lift mode can you tell if they are centered the same as when the loader is not moving?

The dump spool is in the neutral position. The main loader arm spool is opened slightly and the control handle is slightly to the rear. It remains in that position until I move it to neutral. It makes a snap sound when I do so.

If you move the the joystick to raise faster and then stop does the loader now stop moving?

Sometimes it stops, and sometimes I need to manually put the control in neutral. If you hold the control in full lift and let it slip from your hand, it will generally snap back to neutral.

Running the loader today I found that I could have it stick with the engine off, no pressure on the system and the bucket on the ground. Now does this mean that it's a linkage problem? I don't know.

Although I have been unable to load a video here, I was able to send one to my JD dealer showing the loader in operation. I'll wait and see what they have to say.

Best, Bill

 

[J_J]

Have you removed the cans on the bottom of the valve and checked the centering springs. See if the nuts on the end of the spool are tight.

Remove the linkage from the spool and push and pull the spool and see if it still has equal throw and if it still sticks.

There might be some debris in the spool. Remove the spool and check.

 

[Notforhire]

Have you removed the cans on the bottom of the valve and checked the centering springs. See if the nuts on the end of the spool are tight.

Remove the linkage from the spool and push and pull the spool and see if it still has equal throw and if it still sticks.

There might be some debris in the spool. Remove the spool and check.

I haven't put a wrench on anything yet. Because the machine is under warranty I didn't want to dig into it too far. I do intend on disconnecting the linkage, then at least I'll know where the problem is.

Health issues have me out of action for a while. When things normal up I'll get this figured out.

Thanks for the help.

Best, Bill

 

[Notforhire]

Just an update.
I brought the tractor to the dealer, as it was under warranty. They replaced most all of the linkage, and installed a updated bracket that holds the cables. No change.
They disassembled the spool and could find nothing wrong. It still stuck.
They decided to replace the entire valve assembly, and that finally cured the problem.
The new valve, besides not sticking, operates much better than the old unit. I always had trouble feathering the old valve. This one is much smoother.

What actually was wrong, I guess I'll never know.

Thanks again for the ideas.
Best, Bill