A hydraulic device (1) comprises a housing (2) and a gerotor (3) contained within the housing (2), the gerotor (3) having an inner rotor (4) eccentrically disposed within an outer ring (5), the outer ring fixed to the housing having a central axis (19), the inner rotor (4) having external lobes (4a) extending radially outwardly engaging the outer ring (5) having internal lobes (5a) extending radially inwardly, the inner rotor (4) being arranged for orbital and rotational movement relative the outer ring (5), wherein the orbital and rotational movement will define a plurality of expanding and contracting volume pressure chambers (7) between the inner rotor (4)and the outer ring (5). The hydraulic device comprises a fluid feeder tube (8) with a central axis. The fluid feeder tube (8) is provided with at least one fluid inlet line (8a, 8c) and at least one fluid outlet line (8b, 8d). The inner rotor (4) is adapted to slide against a drive shaft cylinder (10b), the drive shaft cylinder (10b) having a circumference which is eccentrically disposed relative the central axis (19). The inner rotor (4) comprises at least one radial fluid feeder channel (9) disposed radially from the centre of and through the inner rotor (4) and out to at least one of the plurality of expanding and contracting volume pressure chambers (7), wherein said fluid inlet line (8a, 8c) and said fluid outlet line (8b, 8d) respectively are radially connectable to said radial fluid feeder channel (9) for fluid communication into and out from said expanding and contracting volume pressure chambers (7).