the ubiquitous problem. I was talking to my Dad, I gave him my DT 9 speed - I asked him if the post slipped. He said "no, but it did on the cheapo/tchibo folder I had before. But what I did then was roll a bit of old inner tube over that bit of the post and it cured it".
FWIW - not something I've come across on here before, perhaps its the answer. Anyone else tried this?