How can I replace the main drum bearing on a Clark's cement mixer?

To replace the main drum bearing on a Clark's cement mixer, first disconnect the power source and ensure the mixer is stable. Remove the drum by unbolting it from the frame, then carefully take off the old bearing, which may require some force or a bearing puller. Clean the area, install the new bearing in the same position, and reattach the drum securely. Finally, check that everything is aligned properly and test the mixer before use.