What is purpose of these hydraulic set screws?

[MichKubota]

On my L3650GST the hydraulic filter assembly has two set screws. What are these set screws used to adjust?

My hydraulic pump looses prime intermittently.

Does anyone know the purpose of these two set screws.

The owners manual and service manual do not say anything about these screws.

 

[rbargeron]

My guess is they're relief valves - one for the power steering circuit and one for the valve block below in the picture. Not sure about whether there might be different shims available corresponding to different pressures - maybe need a gauge to adjust?

It's common for hydraulic filters to be on the suction side of the pump - plugged filter or air in-leakage could starve the pump.

 

[MichKubota]

Thanks rbargeron for input.

Could they also be used as priority valve set points for power steering circuit and for the valve block?

The symptom I have is the 3pt hitch hydraulics work (from valve block) but the power steering isn't working (intermittently) after starting tractor.

 

[leonz]

The drawings "Hoover", but they are flow regulators- they meter the oil flow to the functions. you most likely have debris stuck in the valve or a "plugged filter" that controls the steering.

If they were relief valves they would have springs and poppets.

 

[MichKubota]

Thanks leonz. I would never have guess they were used for flow metering. But that makes sense. Thanks again.