Originally Posted by
MyRedTrek
Btw, the reason I think the original O-ring got worn down in the first place is some corrosion developed at the bottom of the tube. Not sure how that happened but I began to feel this rough spot at the bottom of the plunger travel. Before putting the new O-ring in I attached varying grades of wet-dry sandpaper to the end of a dowel with doubled over duct tape and worked it against the rough area until it disappeared. 320, 800, 2000, 3000 grit. Wiped it out with paper towels also attached to the end of the dowel and shot aerosol parts cleaner down there until the towels came out with no more residue, then re-lubed with Sil-Glyde.
Humidity in the air, as well as compressing air heats it up allowing the air to hold more moisture. It's why air compressor tanks have drains and most compressed air systems have water traps.