One problem related to brake popping noise has been reported for the 1998 Kia Motor Sephia. The most recently reported issues are listed below.
Whenever brakes are applied, they would start to make a popping noise. It would sound like metal rubbing. Took to dealer & informed a nut was left out of the suspension. It was replaced, but vehicle started vibrating again like it's out of balance. The gas gauge does not register right and spose gas out while filling.