Squeaking bicycle brakes can drive you crazy. Squeaking brakes are common when your brake pads dry out and glaze over. If your brakes are squealing, it’s a sign they are not working as well as they should. It only takes a few minutes to get your brakes working like new again.
Unscrew the bolt on the back of each brake pad using the 5mm Allen wrench. The bolt is on the opposite end of the shaft from the brake pad.
Pull the brake pads out of their mounting arms and toward the rim.
Clean the brake pads thoroughly with acetone and a cloth. Let the acetone sit on the pads for about 3 minutes. Rub as much of the glazed surface off each pad as possible. Dry the brake pads with the cloth.
Scrub the surface of each pad with the sandpaper, until the surface feels like a pencil erasure. Put the pads back into their mounting arms. Insert the bolts and tighten securely.
Compress the brake arms against the rim with your fingers. Place the bullet-shaped end of the cable back into the wire cage and release the pressure on the arms.