Too many times we talk to people that have purchased pumps on Ebay or from somewhere else, and then put them right into service. That is not something that we would recommend. The fact is that you don't know if that pump has been maintained properly or not. In most cases they are contaminated. Why would you want to mix someone elses contaminated process in with your own? You wouldn't. Below is a picture of what we too often find when we open a pump.

  You want that crud in your process?