Kubota Pressure Relief Valve

[varmint]

I installed one of those cushion valves like the one J J linked to on my snow blade, and it is easy to adjust the relief pressure, based on the info I got from one of the techs at Surplus Center- when on side of the 78" blade hits something immovable, I can see the blade give before there's any damage.

 

[Stonehaller]

I installed one of those cushion valves like the one J J linked to on my snow blade, and it is easy to adjust the relief pressure, based on the info I got from one of the techs at Surplus Center- when on side of the 78" blade hits something immovable, I can see the blade give before there's any damage.

I don't think the cushion valve is what you want for a thumb cylinder. Cushion or cross over relief valves will let oil from one side of the cylinder flow to the other side when it exceeds the relief setting. Ok for hydraulic motors or dual angle cylinders on a plow but not for a single rod cylinder on a thumb where the volumes on each side are not equal. The cushion valve would work while the valve for the thumb is activated which would protect the bucket cylinder from being over powered by the thumb, but typically you need protection the other way, to prevent the bucket from over powering the thumb and that is where the cushion valve would not help. He needs work port reliefs with cavitation makeup that will dump pressure to tank on the side exceeding the port relief setting and draw oil from tank on the low pressure side. That is probably what the Kubota valve is.

 

[J_J]

You could add a work port relief, but he said he did not want a third line which is the tank line.

 

[drivadesl]

Hey guys thanks for the good info! The Kubota mechanic conceded there are aftermarket parts that will work, but ended it there. I could operate the thumb if careful, but if not, could end up damaging something serious so I do want to set it up correctly Interestingly he commented $520 for a dinky valve like this seemed even high to him.

Based on what I'm reading from you experts, the cushion valve is not the way to go. I'm more inclined to want to use the OEM parts, or at least the OEM concept for the OP relief, but was looking for a less expensive option. Adding another hose onto the boom is not what I want. I was out of town since yesterday so didn;t get a chance to contact Messicks but will try when I get a chance.