Sometime back (approx. 5000KM) I changed front disk pads of my City i-DSI. I used OEM pads. After about 3000KM of changing the pads, I noticed that the brake performance has significantly decreased and the brake pedal vibrates while hard braking. I know the common diagnosis suggests it to be faulty brake rotors. But what other possible reasons can there be? Could it be improper bleeding of the brake system while changing the pads? faulty caliper pistons and pins?
Any suggestions and help will be deeply appreciated.