A clutch actuator provided with a clutch assembly, comprising: an actuator housing ; a piston assembly disposed within the actuator housing and movable between a first position and a second position, the piston assembly configured to selectively change a clutch state between an engaged state and a disengaged state, the piston assembly having a piston head , an elongate member extending from the piston head , and a lock ring coupled to the elongate member ; a bearing carrier that supports a bearing , the bearing carrier slidably disposed on a portion of the actuator housing; a locking element operatively connected to the piston assembly and engaging the bearing carrier to adjust a total length of the piston assembly as the piston assembly moves from the second position towards the first position to compensate for wear of the clutch assembly; and a release ring connected to the actuator housing , the release ring having a collar that selectively engages the locking element in response to movement of the piston assembly from the second position to the first position; characterized in that the clutch actuator is a pneumatic clutch actuator, that the collar extends from an end of the release ring , that the release ring extends through a slot formed within the elongate member , that the locking element includes a first locking element end received within a groove which is defined by the elongate member and the lock ring and a second locking element end that engages the bearing carrier , wherein while the piston assembly is in the first position the piston head is disposed proximate a floor of the actuator housing and the collar engages the second locking element end to pivot the locking element to adjust the total length of the piston assembly , wherein while the piston assembly is in the second position, the piston head is spaced apart from the floor and the collar is spaced apart from the second locking element end. an actuator housing ; a piston assembly disposed within the actuator housing and movable between a first position and a second position, the piston assembly configured to selectively change a clutch state between an engaged state and a disengaged state, the piston assembly having a piston head , an elongate member extending from the piston head , and a lock ring coupled to the elongate member ; a bearing carrier that supports a bearing , the bearing carrier slidably disposed on a portion of the actuator housing; a locking element operatively connected to the piston assembly and engaging the bearing carrier to adjust a total length of the piston assembly as the piston assembly moves from the second position towards the first position to compensate for wear of the clutch assembly; and a release ring connected to the actuator housing , the release ring having a collar that selectively engages the locking element in response to movement of the piston assembly from the second position to the first position; characterized in that the clutch actuator is a pneumatic clutch actuator, that the collar extends from an end of the release ring , that the release ring extends through a slot formed within the elongate member , that the locking element includes a first locking element end received within a groove which is defined by the elongate member and the lock ring and a second locking element end that engages the bearing carrier , wherein while the piston assembly is in the first position the piston head is disposed proximate a floor of the actuator housing and the collar engages the second locking element end to pivot the locking element to adjust the total length of the piston assembly , wherein while the piston assembly is in the second position, the piston head is spaced apart from the floor and the collar is spaced apart from the second locking element end. <EOS>