Knocking noise KOK KOK KOK -situation when driving on uneven road will produce KOK KOK noise ,after apply brake the knocking noise will gone .
*REASON -
the brake caliper wear and tear ,caliper hole will bigger than original size ,so the clearance between the caliper pin and caliper hole is too large , knocking will occur when driving on uneven road.

*RESOLVE- change OVERSIZE caliper pin to reduce the clearance 

****some workshops put grease in the caliper hole to refit the clearance (but after the grease gone, the knocking noise will came back )