A rotor reversing mechanism for a baler comprises a ratchet 12 mounted for rotation with the rotor, a pawl 22 carried by a reversing arm 16 for engaging the ratchet 12, a double acting hydraulic cylinder 32 for reciprocating the reversing arm 16 to cause the rotor to rotate in a reverse direction and means for disengaging the pawl 22 from the ratchet when the reversing arm is in a park position. In the invention, a spring 40 is provided for urging the reversing arm 16 towards the park position and the working chambers of the double acting hydraulic cylinder 32 are permanently connected to one another by way of a throttled passage 74.