Maruti Suzuki India says that they are replacing some defective parts in as many as 28,500 cars which inlcudes popular models like Wagon R,Alto and Zen Estilo. A problem such as this usually surfaces after a car has travelled 7,000-8,000 km. Each drive shaft costs about Rs3,000. These parts are being replaced as the vehicles are brought to any of their service centers in the country. The cars with the defective parts were manufactured between May 2006 and February this year. The defect in the parts is due to defective greasing in the shaft and these shafts were manufactured by Delphi Automotive Systems. Maruti said that the defect does not cause any safety problems for the passengers in the vehicle.