SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

Help!! I have a valve that suddenly stopped flowing. There is 24 VAC at the solenoid, which is spec for my timer box. I have all Hunter PGV valves in my system. Manually opening the solenoid did no good. I purchased a new Hunter PGV valve, took off the top, and installed all the new components in the bottom half of the old valve. I ran a wire through the exhaust port to be sure it was clear. Still no water. I repeated the above with different solenoids and carefully installing the new valve parts 4 times and still no water. A blocked exhaust port sounds like the most logical problem, but I ran a wire through both the port under the solenoid and in the lower body of the valve each time. The valves I have in my system are 8-10 years old, but my understanding is that the components of the new valves can be used as replacements. I swapped parts to fix a leaking valve about a month ago and everything worked fine. Anybody have any thoughts as to what I can try next other than cutting pipe and installing a new valve?
Thanks,
Mudman