Koyker 310 loader bleeding off.

Hello all thanks for letting be here !
I have been weeding through searches and have not been able figure out my problem.

I have a 1968 JD 4010 with Koyker 310 loader.

Things I know

I had algae growing in the hydraulics when I bought it four months ago. The screen,filter and fluid is now clean.
The loader is weeping off. It floated down
I took the lift arm lines loose and blocked them off with plugs while the loader was in the air. The loader did not move for the two days it was this way. So the seals should be good in the lift arms ( I think)
I then reassembled and flipped the lines. Now with a 1200 lbs round bale the loader slowly lifts stil instead or floating due to the line reversal.To the point I have lower it quite often to use it.
I then took the spool valve apart that feeds the lift arms. The internals are metal on metal. I have a picture of the shaft. There is slight wear but no dirt and no gouges. Also it still has a real tight fit. I did not remove anymore lines or any other parts to the spool valve.
The rotation on the bucket does not bleed off as far as I can tell.
It seems something is not sealing off but I am not sure what.

Let me know any other information you need or pictures.

Thanks Mike

Sounds like the valve is not centering. With the engine off, can the creeping down be stopped by slightly holding the lever off center? If so, can you find a way to correct the center return stop?

If it still creeps down, try plugging the pressure and return port from the valve. If that stops it, the valve is bypassing. If it creeps with the ports plugged, the cylinder seals are leaking.

It wouldn't be the first time an add-on loader valve (or an OEM JD SCV) developed a crack or pinhole in the casting.


Reading between the lines of your post, you must have an add-on valve, and, likely, the only fix is going to be to replace it.

(quoted from post at 09:07:53 01/16/15) Sounds like the valve is not centering. With the engine off, can the creeping down be stopped by slightly holding the lever off center? If so, can you find a way to correct the center return stop?

If it still creeps down, try plugging the pressure and return port from the valve. If that stops it, the valve is bypassing. If it creeps with the ports plugged, the cylinder seals are leaking.

Click to expand...

I will try this.....

Bob. Interesting on the spool valves. I guess I am too believing. I would have never thought it possible but now you mention it, it does not suprise me. Thanks

--- Also the bucket tilt is bleeding off but at a much slower rate

Mike

It does not take much wear on a control valve to leak, it is just metal on metal.

(quoted from post at 11:26:30 01/16/15) It wouldn't be the first time an add-on loader valve (or an OEM JD SCV) developed a crack or pinhole in the casting.


Reading between the lines of your post, you must have an add-on valve, and, likely, the only fix is going to be to replace it.

Click to expand...

The control valve is whatever Koyker provides. I am not sure of the manufacturer.

Mike

The bucket tilt is also bleeding off. Does this change any thoughts ?

Mike

Do the same test as you did with the lift cylinders... support the bucket, cap off the lines, then remove the support from the bucket and see if the cylinder leak down internally.