TC reported front M1 car 'A3' door slowin closing. Staff (WDL) checked and confirmed thatfront M1car 'A3' door closed slower than the other doors. ~~~~~ 1529 TC reported 'A3' door slowin closing. Staff (WDL) confirmed that front M1 'A3' door closed slower than the other doors.  1529 A3 door manifold air leaking during door closing. Replaced manifold. Function test door open/close operation & door gauge test - OK.  Chan GF/Alan    43969