Just put a 4-Way Swinger on my AC and had a heck of a time getting the SPV to hold air (leaks out when you detach the pump) when setting the SPV pressure. I understand this is VERY common and is truly a PIA. So I pulled out the valve core and filed off about 2/3 of the plunger head (just a few thousandths of an inch), cleaned the core, and put it back in. Bingo, now the valve closes before the o-ring breaks the seal when you remove the pump hose.
Takes just a few minutes - no more fighting with the valve. Just push the plunger all the way in before you hit it with the file, so you don't bend the plunger shaft.
Takes just a few minutes - no more fighting with the valve. Just push the plunger all the way in before you hit it with the file, so you don't bend the plunger shaft.