We have an 05 plate citroen c3 1.4 diesel, early this year we had the front brake pads and discs changed as we could hear a high pitch whistling noise, the pads were indeed worn out and the discs were in need of a change. Anyway since then it occasionally happens and sometimes its louder than others(to the point it can be heard over the stereo), yet whenever we touch the brakes even just slightly it stops, then starts again as soon as you take your foot off. It doesnt happen all the time just now and again and it seems when were at high speed. I recently took the front wheels off with my father in law and noticed that the pads on the offside front disc were virtually stuck to the disc, after freeing it up we checked the nearside and this wasnt as bad, it seemed to work straight away no noise but its come back again, and its hard to show people as sods law determines it doesnt happen when you want it to, does anyone know what could be the problem?, theres no knocking noise its just a high pitch screeching type of noise (hard to explain). Any help would be much appreciated