The filter member includes a filtering part to filter oil, a second orifice to rectify oil flow, and a check valve to permit oil to flow back when braking operation is released.

Need to check the oil box's bottom which outlet whether closed or not, after closed surely then open the top of oil box and add the sealing cover for the top orifice.

This oil outlet passage feeds oil from the outlet of the orifice to a space defined under the bottom of the valve housing.