oliver wheel disc

I have an oliver wheel disc, about 12 - 14 feet wide, and I still use it in my farming operation. I&#039;m not sure but one fellow tells me it&#039;s a model 242. I would like to get some replacement parts for it (disk cleaners, etc.) but I need to come up with part numbers. Does anyone know where I could buy a parts book for it? I can be e-mailed at: <!-- e --><a href="mailto:alcowain@dmci.net">alcowain@dmci.net</a><!-- e --> 
thanks for any help, Al