EB departing. Reset EB ok. TC feedback BCU fault at Rear M1 car. ~~~~~ Check and found #1642 having stuck brake. Further found air leaking from solenoid course exhaust v/v when B1 to coast. Replaced ACU and conduct brake cyclic and function tested ok. BCP in range. Not: 2121007. #1642-ACU- New s/n: 1937-230.  Old s/n: 1511-089. Done by Alauddin/Kamal. 15/01/20.