Brother DCP-L8400CDN Service Manual page 461

(3) Remove the Shaft of the Back cover from the Bush on the right side of the Main body.
Main body
Bush
Back cover
<Back side>
(4) Remove the Back cover.
Fig. 7-3
4a
4b
Fig. 7-4
7-4
Main body
<Back side>
Back cover
Shaft
Confidential