1, the brake on the wear alarm switch has been alarm when the alarm.
2, when the brake pads are contaminated with oil or grease.
3, brake pads in the brake when there are abnormal sound. Under normal circumstances, if the fixed brake calipers on both sides of the brake pad thickness difference of 1.5mm, the floating brake caliper on both sides of the thickness of the brake pads to 3.0mm when the need to be replaced. However, only through a simple appearance observation can not accurately determine whether the brake pads wear, it is best to use ruler to measure the thinnest brake pads to see if it is within the allowable range