If you are using brake pads I usually toe mine in it is a simple thing to do first loosen the pad from the caliper insert between the rim and pad a piece of car folded in half at the back of the pad then tighten up the bolt this usually works for me but whatever you do please don't do what a mate did and spray them with oil
Squeaky brakes can be caused by many things. Most likely you have brake pads. They may need to be adjusted slightly so they are not touching the rim of the wheel where it brakes. Second, check if the cables are not too tight or too loose, they need to be almost perfect tension in order to operate correctly. Third, make sure your brake pads are in good condition, if not, you may have to buy new ones. Finally, if you have not been using your bike for a period of time, the brakes do make a squeaky sound and will dissipate as you use it.
Squeaky brakes on both bikes and cars are the result of the brake linings becoming polished. The remedy is simply to remove the blocks and roughen the surface with coarse emery paper.
You can do one of two things booth require disassembling the breaks cheeap way put a double layer on the back of pads. Or simply buy a can of compound and spray back side . Either way works well. If you paid to have the breaks done simply return w your complaint this may take 2-3 visits but they will fix them
