Replacing the drum in a Brother printer is essential for maintaining print quality. Start by turning off the printer and unplugging it for safety. Open the front cover to access the drum and toner assembly, then carefully pull out the entire unit. Release the toner cartridge from the old drum by pressing the release lever, and attach it to the new drum, ensuring it clicks securely. Slide the new drum and toner assembly back into the printer, making sure it’s seated properly.