I'm getting a suction side leak on the window of the check valve before it hits the pump ( I can see the air bubbles) . When I went to unscrew and examine the situation I noticed 3 of the screws don't screw firmly anymore. I tried the toothpick trick which usually works for me on wood projects , but it didn't . Anyone have an idea ? Can I re-tap it ? Or do I need to replace the check valve entirely ?