I also have PD-M505 pedals on my OCR, and couldn't find anything on the Shimano website about them. So...I searched the web and found the service instructions and parts breakdown in .pdf file format. I can't upload to this forum due to size limits in the forum, but below are links where you can download them yourself....
http://www.paul-lange.de/ftp/SHIMANO/epvusi/VPDFS/SI_EN/45C0B_EN.PDF#search='Shimano%20PDM505'
http://www.orangebikes.co.uk/technic...LS/PD_M505.PDF