Well you answered your own question Skip! when you sanded the surface you probably made a wedge out of it. Plus the scratches from the sandpaper are a path for leakage. Metal seals have to be smooth and parallel. They don't have to be thick, just uniform in thickness. The standard thickness is usually a 1/32". You shouldn't have to tourque these down to get a seal.
Denny Graham
Sandwich, IL
