Set the length of insertion between coupling and hydraulic pump shafts so that it is within at least 2/3 or more of the coupling width.
Use a sufficiently rigid pump mounting base.
Set the pressure on the pump suction side to -0.03 MPa or more (suction port flow velocity within 2 m/sec).
Raise part of the drain piping to above the topmost part of the pump body, and insert the return section of the drain piping into the hydraulic fluid. Also, observe the values in the following table to limit the drain back pressure to 0.1 MPa.