Sticky 3rd Function Valve

[bdhsfz6]

I have W&R Long 3rd function valves on my Kubota L6060 HSTC and MX5800 HST tractors. Both valves stick open in either direction when operated at high engine RPM. It's particularly annoying when using a FEL mounted plow.

Anyone else notice this problem and if so, is there a fix other than dropping the RPM?

 

[K5lwq]

Do you know the flow rate for the valves? Could be you are exceeding the flow and the spring is not strong enough to close? Only thing I can think of if it works at lower RPM.

 

[bdhsfz6]

Do you know the flow rate for the valves? Could be you are exceeding the flow and the spring is not strong enough to close? Only thing I can think of if it works at lower RPM.

I'm not sure of the flow rate but I'm using the valves to control cylinders with .045 flow restrictors. The flow can't be that high.

 

[TractorGuy]

I'm not familiar with the setup you have but I assume these are solenoid valves.

Could it be the switch sticking?

I used a starter switch on my home brew diverter and my switch got dirty and caused trouble for a while. I sprayed it under the boot with WD-40 and that fixed it.

 

[K5lwq]

I'm not sure of the flow rate but I'm using the valves to control cylinders with .045 flow restrictors. The flow can't be that high.

Can you remove the flow restrictors for a test? It may be that they are holding to high of back pressure at high RPMs. If you remove the restrictors and works properly then that would be the case.

 

[bdhsfz6]

I'm not familiar with the setup you have but I assume these are solenoid valves.

Could it be the switch sticking?

I used a starter switch on my home brew diverter and my switch got dirty and caused trouble for a while. I sprayed it under the boot with WD-40 and that fixed it.

Yes, they are solenoid valves. The problem happens on both tractors so I doubt it's the switch. It also started shortly after they were installed.

 

[bdhsfz6]

Can you remove the flow restrictors for a test? It may be that they are holding to high of back pressure at high RPMs. If you remove the restrictors and works properly then that would be the case.

It's worth a try but the problem also happens when running a hydraulic motor without any restriction.

 

[MinnesotaEric]

Take apart the valve and take some fine sand paper and remove the rust.

Alternatively, take apart your double acting electric over hydraulic valve and inspect it for rust on the valve body as well as on the end of the valves itself as I doubt you have an intermittent failing winding.

Alternatively, replace your replays with known good relays to confirm your intermittent issue isn't a faulty relay--aware that as you do so, some relays are not good in the cold because their grease thickens too much in the cold causing symptoms like your fault.

Moreover, before doing any of those things you could check any and all connections for corrosion.

That said, if you hold this post upside down, you'll have the correct diagnostic ordering. Smile.