So while doing the leak test this morning with some soapy water to reveal the exact location of a fin box leak I have discovered my vent plug is leaking almost as bad as the fin box crack. Never been a fan of over tightening the screw with fear of pinching the O-ring but from firm to over tight (in my opinion) it still leaks. O-ring is fine but seating area is questionable.
Any advise on refurbishment of seat area, larger O-rings or maybe a smear of grease to guarantee seal?