hahahaha. disc brake damn expensive lah.
Maybe your brake pads too hard olready.
My advice,
Either change the brake pads
or
cycle very fast and brake hard to wear down your brake pads a lil
bit, it does work for me, the sweaking dissapeared
or (last method)
get some greese and put on the brake pad surface (don't put alot if
not arr wah, you know what will happen lah)