I have an occasional small drip leak at the fuel sample drain after sampling. I can push the plunger in three or four time and most times stop it. I had recently replaced the drains as I was having this issue before (I know I could have just replaced the o-rings, but decided to replace the whole drains) but I'm still having it. Is there a better way to address this and prevent this type of drip leak besides not sampling the fuel (which will eventually bite me, I know)?