An old trick for softening the rubber idler wheel found on those electric record players of the 1950's is to soak the rubber wheel in transmission treatment that is used to make old transmission seals soften up. Some brake fluids will also work. If the wheel is really rock hard there is not much you can do except make a new one. I went to an old hardware store and found a rubber gasket that worked for a neighbor of mine but finding something that would be the exact size is a matter of luck. Good luck, Al