Loader Valve / Curl function diagnosis

[GPintheMitten]

I have a Kubota B2620 with the LA364 loader. The boom raises and lowers fine but the bucket curl won't dump.

I switched the quick disconnects to test. When switched the bucket curls but the boom doesn't work. So I switched them back.

I took the loader valve off the tractor, both spools seem to be moving up and down the same amount. I took it to a local hydraulics repair place and this perplexed the guy there. He said it is rare to have the loader valve fail. He connected 2 pressure dials, one to each outlet for the curl and told me to replumb it and check pressure.

After running the boom up and down several times to bleed air, I tried the curl function. Immediately one meter pegged high but as soon as I released the joy stick the pressure bled off. I then moved the joy stick the other way, and there was no pressure on the other curl outlet. This seems to verify that there is an internal fault in the control valve for the curl function.

Does this sound correct? If so, I can buy a new Kubota loader valve for $500. I would like recommendations whether to do that or try and have this one fixed.

If I have this one fixed, there are apparently 2 different versions of this valve and I have to determine accurately which I have before ordering the internal parts. My tractor is serial number 51216. My loader serial number is A3130. But I think it is the tractor serial number that governs the loader valve.

Help please. Thanks.

 

[J_J]

Look at these valves and see if any fits your situation.

Surplus Center

 

[GPintheMitten]

I'm sure there are a couple that I could make work. But I would have to replumb everything. My valve is mounted to the side of the transmission behind the fender with hard lines with banjo fittings for all except a rubber hose for return. I'm not sure the cost savings on the valve would be worth the time effort and costs to replumb.

 

[GPintheMitten]

Does the test with the pressure Guage that I describe prove that it is an internal fault in the control valve?

 

[J_J]

Did you see fluid coming out of both the curl work ports?

You might have a nut off the end of the piston, allowing some pressure in one direction and none in the other direction.

 

[GPintheMitten]

Did you see fluid coming out of both the curl work ports?

You might have a nut off the end of the piston, allowing some pressure in one direction and none in the other direction.

The only thing on both curl ports were gauges. They weren't T'd in.

As to the pistons, a previous test was to switch the quick disconnects between the boom and curl. With them switched, the curl worked but the boom didnt.

So do you think I have sufficiently diagnosed it to the control valve?

JJ I appreciate this help.

 

[J_J]

If you have regen, it might affect your readings.

Try the valve curl lever to the far right which should be power dump.

I would check the pressure by installing the gauge in the IN port of the valve.

 

[GPintheMitten]

I don't know of it have regen or not. How would I determine that?

 

[J_J]

If you have regen, there are two dump modes, fast dump and power dump.

On some valves, the regen is in the first part of lever movement and other valves it is to the far right.

In regen you may not be able to raise the tractor off the ground using the bucket curl, but in power mode you should be able to raise the front wheels off the ground.

 

[LD1]

On my kubota, first position to the right is regen, second is power.

maybe I missed it, but you did not say which direction dont have pressure? dump or curl?

Are you 100% sure you are on the right hoses?

In regen mode, BOTH ports should see pressure. In power mode, only the hose going to the base end of the cylinder will have pressure. In curl, only the rod end hose will have pressure.

What is the PSI range of the gauges? If you are using 0-3000 or 0-5000 gauges, its possible that an empty bucket just dont have enough weight/resistance to notice a pressure reading. Try ditching the hoses and hook the gauges straight to the valve?

Any pictures of how you are testing it now?