bought two corny kegs off of ebay. the guy had 100% feedback. They didn't hold pressure. one leaked at the lid, the other at the poppet valve. Let the guy know, he sent me two new ones no charge. Cool, right? Both the new ones leaked at the lid. Let him know, waiting to hear back. Tried new o-rings they still leak. Switched out a valve on one and it's ok. So I have three that leak at the lid. I tested by filling with CO2 and spraying soapy water on the lid and valves. Has anyone dealt with this, and was able to fix it?