Re: Squeaky brakes
your brakes need complete service, new pads(old ones refitted not good), clean caliper thoroughly with brake cleaner and make sure there is no crap on the edges where the pads sit, remove rust from disc edges by spinning and using screwdriver to hone off.
if you can, pump out piston and replace rubber seals with extreme caution and cleanliness. copper grease all contact surfaces between caliper/piston/pads but not between disc/pads obviously.
And dont forget to run pads in for a while to bed them in, otherwise you'll be back to square one.