Sharp Optonica RT-3838 cassette deck repair

This video describes how to disassemble the tape recorder mechanism in order to get to the fly wheel, where you can exchange the belt and exchange the rubber sleeve on the capstan axis. This rubber sleeve is needed to rotate the take up spool properly. The problem is similar on many Sharp cassette deck models. In the video I mention teflon as a possible material to use. I am not so sure anymore. Maybe this material is silicon rubber based - I do not really know for sure. It is really not that critical. The material needs to have friction and it has to be flexible.