Because I don't want to spend time and money to send it back to them,my next attempt will be to build from the start a new one idler wheel acrilic with o-ring rubber. As far i know torqueo audio
in Italy are excellent re builders about Rek-o-Kut turntables http://www.torqueo-audio.it/olive/
Also is a good choice to build a new pulley to work properly at 50hz under load.
I spoke with them and they are able to build an idler wheel and pulley at my own specifications,
fingers crossed until i receive the items...