a seat sliding apparatus for vehicles is provided . the seat sliding apparatus includes a track and a guide bracket with legs connected to stepped locking pins to regulate the locked state of the locking pins which engage the track . in one embodiment , the track includes through - holes which are engaged by the locking pins . accordingly to another aspect of the apparatus , a plastic bushing is provided to prevent horizontal / vertical floating of the locking pins , thereby minimizing the play of the locking pins and prevent floating . the apparatus also may simultaneously prevent a half - locked state of the locking pins .