SA (SBW) feedback to SM (SBW) door 18 was not fully close when at station. Staff (YIS) checked and c onfirmed, door was able to fully close however door was emit ting jerking noise when closing. Train was reformed with T40 ~~~~~ 1610 SA (SBW) feedback to SM (SBW) door 18 was not fully close when at station. Staff (YIS) confirmed, door was able to fully close. However door was emitting jerking noise when closing. Train was reformed with T40.  1610 B3 door found LHS jerking violently. Removed door & found both big rollers worn. Replaced the door leaf rollers. Door function check - OK. Door gap = 63.5mm. Door open/close - OK. Cleaned J-rail. Door open/close timing checked - OK. No DIR found lit & all doors proven closed.  Sarma/Sugu/Lee PT 44971