Here's a google link to pictures of allis chalmers disks. Copy and paste the link into your adress bar.
Here's a link to my method of rebuilding the old allis chalmers disk bearings
If it is an old Allis disk it has balpak proprietary allis bearings. These are about $250 from AGCO. If you want to do a little work you can rebuild them from the article above. If you have any questions just ask.