A method comprises receiving a displacement signal generated by a sensor, the displacement signal generated by the sensor in response to detecting movement of a piston from a retracted position in a cylinder toward an extended position in the cylinder. The method further comprises generating, in response to receiving the displacement signal, a valve control signal to be communicated to a valve located on a vacuum line connecting a vacuum source to a vacuum port of the cylinder. The valve control signal causes the valve to move from a first position in which a vacuum pressure is applied to the cylinder via the vacuum port to a second position in which atmospheric pressure is applied to the cylinder via the vacuum port.