Help with tape deck

Hello everyone! I changed the idler tire on my Nakamichi BX-300. By accident, I lost the clear plastic washer that goes in front of the idler wheel (that which prevents it from going off the hub). Can anyone please help me find a replacement? Thank you very much.
Get in touch with Willy Hermann. You can find him online. If anyone will have it, Willy will. 
Thank you very much! Take care and stay safe and healthy.