The toner cartridges and the drum unit are two common components in almost all Brother Printers. The cartridge contains the powder needed to print while the drum unit is needed to transfer the toner onto the paper while printing. The drum unit slowly deteriorates with use and needs to be replaced once you go through 3 or 4 toner cartridges. The printer will detect the quality of the drum unit automatically and alert you when it needs to be replaced by sending out a ‘Replace Drum’ messages on your computer. The drum unit replacement instructions are different for different printer models. You should contact Brother Printer Support Number or check the user guide for more information about the specifics of your printer model. This article will give brief instructions on how the replace the drum unit in a Brother MFC-L27700DW. This is a very common printer model which uses TN660 cartridges along with a DR630 drum unit. If you find that your printer has similar specifications then you just need to follow the steps given below to resolve the ‘Replace Drum’ message.