When your brake lights keep blowing fuses, it probably means that you have a shorted socket.
Try removing the bulbs and checking sockets for any corrosion, then install a test light in place of a fuse in the fuse box, it will glow when the brake pedal is depressed. This will mean that there is a short present.
If this is happening often, then have a professional check it out immediately. He will also be able to determine the main cause of why your socket got shorted in the first place. In all probability, it shouldn't cost you more than £20 to £30.
Good luck Neil.
Jack [of all trades but master of non!]
May 2014