Loader Valve / Curl function diagnosis

J_J · Sep 15, 2015

Your only other option is to tee each gauge in each work port with cyl connected.

A test set like this would have worked well.

GPintheMitten · Sep 15, 2015

Thank you JJ and LD1. With guages directly mounted to the curl ports on the loader valve (not tee-d in), when I push the joystick out to the right, the top guage shows max pressure (2000) and when I let the joystick go, it bleeds back. Then when I push the joystick back in to the left, the bottom guage stays at zero. So I can't see any reason to plumb the hard lines back and open the lines at the cylinder to check on oil flow. With no pressure on the lower guage, it seems to me and my local hydraulic guy that the problem is internal to the loader control valve.

I'm shopping for a new or used loader control valve now. Thanks again.

GPintheMitten · Sep 15, 2015

Btw, I just took the guages out and reattached the curl lines, removed both quick connects from the lines. I applied pressure and got oil flow on one line but zero oil flow the other way. One last test verified no flow.

LD1 · Sep 15, 2015

It does sound like a valve.

ITs hard to see in that picture, where you lines are hooked, but is that the actual valve? How is the joystick connected to that? There could be a problem with a linkage or something that when you pull the lever to the left that you arent actually moving the spool...

GPintheMitten · Sep 15, 2015

LD1 said:
It does sound like a valve.

ITs hard to see in that picture, where you lines are hooked, but is that the actual valve? How is the joystick connected to that? There could be a problem with a linkage or something that when you pull the lever to the left that you arent actually moving the spool...

Yes that is the actual valve. I wasn't sure the spool was moving either but after I took the valve off, and removed the cans from the bottom, I could see the spools were moving. I could also see them moving from the ports.

I ordered a used valve this afternoon. New from Kubota was an astronomical $825 plus shipping. The used one I ordered is guaranteed for 1 year and cost $675. Still outrageous but I need it and didn't want to buy a universal valve and have to find a place to mount it and then replumb all the lines.

LD1 · Sep 15, 2015

Whats the return policy, just in case this turns out to be something different?

GPintheMitten · Sep 15, 2015

I'm beat now but later I will remove the current valve and take some better pics. With the rear tire off, fender off, and backhoe subframe off, I can wiggle the valve assembly out with joy stick attached.

GPintheMitten · Sep 15, 2015

LD1 said:
Whats the return policy, just in case this turns out to be something different?

Not sure of the return policy but I would think I could return it with some sort of restocking fee. After all, it is a used part.

GPintheMitten · Sep 15, 2015

Here's some pics of the loader valve. The linkages are tight and working. This mounts to the right side of the transmission housing, a few inches forward of the axle. When mounted the joysticks lines up along the right leg halfway from the hip to the knee. The goldish colored assembly is a locking mechanism that can be engaged to keep the joystick from moving.

You can't see it in the pics but I can look in the 4 working ports and see each spool move up and down as the joystick is moved.

I will remove the back plate that attaches to the tractor and the joystick and locking mechanism and remount them on the new loader control valve when it comes.

I will report back in a few days after I get it back together. Hopefully all this diagnosis was correct.

LD1 · Sep 15, 2015

Really odd that the spool is actually moving yet no movement of the loader, and the other functions work.

Hope the new valve fixes it. Maybe tear apart the old valve and see if something is broke or cracked