Aligning the brake caliper to the disc rotor is a quick, simple adjustment and can be a solution for squeaking brakes. 5mm allen wrench required.
1) Slightly loosen the two 5mm bolts shown below. Do not remove them. The caliper should now move when pushed side to side.
2) Squeeze the corresponding brake lever AND HOLD IT.
3) With pressure still on the brake lever, securely tighten both bolts.