Originally posted by: AMDMaddness
the rod you pull up and down on is connected to another rod on the drain down tube there should be a nut type metal or plastic thing on the back of the drain that has a rod going into it. I'm betting that its loose try a couple of turns on it but dont overtighten as you can break it.
here is a pic
sink.JPG
If its tight than its worn out and you will need to replace the whole drain or maybe if your lucky find some new plastic washers (they range from $7 and up for the complete unit they are called amny things but its a tailpiece for a vanity sink)