I have a very old Rainbird sprinkler system. The valve that controls the amount of water to system is leaking when turned on. This leaks constantly when one whether sprinklers are on or not. After cleaning i found a part number of Rainbird ASV-75. So I figured easy to find I have a part number. Cannot find the correct part or the corresponding new part number if there is one. I have been to big hardware stores, small hardware stores and the internet. The problems is that none of the parts or new asv valves look the same as mine. So looking for some expert help. I have not taken apart the valve, as I have to shut off the water to house to do so and if I can't put it back together or cant find the correct part once it is off, I am up a creek without water. So looking for advice, crossover part number or anything that can help me to fix my leaking problem.
thank you in advance