Just bought a 1989 Case skid steer 1845c diesel with no service manual. I'd like to change the fluids out as the hydraulic oil is contaminated with water. Where is the drain plug for this job located? What is best way to purge fluids in the lines and hydraulics? Also I would like to change the fuel filter it is a diesel. Other than purchasing a new one filling it with diesel and screwing on is that about it. Thanks in advance.