If the valve cover is secured by 8 screws, with a stainless steel strip underneath, then they are Richdel R204 valves, and serviceable forever. The valve is now known as the 205. If you need to rebuild, it's often easier to just replace the 'guts' and not worry about finding individual parts. http://www.sprinklerwarehouse.com/Irritrol-205-Series-Remote-Control-Valve-p/205tf.htm