A method for monitoring health of a hydraulic fluid subsystem is presented. The method includes determining a plurality of forces acting on an actuator of the hydraulic fluid subsystem, determining a plurality of parameters based on at least one of an actuator inlet flow rate, an actuator outlet flow rate, and the plurality of forces acting on the actuator, receiving a valve inlet pressure of at least one of oil and gas flowing through a pipe while entering a valve operationally coupled to the actuator and a valve outlet pressure of the at least one of the oil and the gas flowing through the pipe while flowing out of the valve, and monitoring the health of the hydraulic fluid subsystem based on at least one of the plurality of parameters, the valve inlet pressure, and the valve outlet pressure.