You will need
  • liquid key;
  • - screwdriver, pliers, adjustable wrench;
  • - drill;
  • - welding
Fill the hole with the broken bolt fluid that can ease your work. It can be a liquid key, or a universal lubricant. They are, after a while, when the connection is cleared.
Inspect the bolt head. If the corners are torn and no longer pose a clear hex, then if the bolt is not very large, then take the pliers. If the bolt is large, then instead of pliers, use a pipe wrench. Position the pliers at a right angle to the bolt. Try to Unscrew the bolt that way.
In the absence of the head bolt, if the bolt is large enough, then the smallest drill bit to make the bolt line 2-3 holes, powerlaw, so the groove under the screwdriver. Inserting a screwdriver into the drilled groove, remove the bolt. The screwdriver is better to take T.
If the head is broken but the part of the bolt protrudes slightly, for it's also possible to grab with the pliers. The combination of pliers and cut the groove under the screwdriver, using two instruments increases the probability of successful extraction of the bolt.
Try using welding to weld to the broken bolt the right size nut and then remove the bolt using the nut as a bolt head.
Drill out the bolt if it has no head, and the bolt is small. This is the most devastating method of extraction of the bolt. To do this, in the center of the bolt drilled hole. The drill start with a smaller diameter than the bolt, because it is possible that the reverse switch on the drill, the bolt will turn with the drill. If not, the hole can be lightly hammer a flathead screwdriver of the appropriate diameter and try to remove the bolt with it, or drill out bolt drill bit of the same diameter.