Removal of rusty dynabolts from bricks

[Russ42]

I have quite a few places where dynabolts have been put into the bricks in the past and have since rusted up badly making them thus far impossible to get out. The rusting is expanding the bolts and breaking the bricks (see photo)

The bolt itself has broken off inside the surrounding metal cylinder. I have a plan A and a plan B.

A. try to drill out the metal cylinder until the drill hits the bolt. Then.......try to drill out the bolt and cylinder together. Perhaps, in the process, the drill bit will grip the cylinder and cause it to spin, thus making it possible to remove.

B. use a  "Vacuum Diamond Dry Drilling Tile Drill Bit" to drill it out. I foresee problem with this.

1. The hole produced will be large and must be filled.

2. if the drill tries to drill the metal of the bolt, it will lose the diamond chips on the end and be rendered useless.

Is there a tried and tested method of removing these pesky things

[Russ42]

@Beavau, 

I used the core drill on the dynabolts which worked fine and did it pretty easily. It was fairly easy to avoid the sheath around the bolt, which is pretty soft anyway, I think. I only needed to drill in about 20mm as that was enough to get the "sheath" out and then the bolt. Just tap the bolt in to allow the sheath to come out. The hole it the same size no matter how deep you drill so may as well give it s solid go as the scar will be the same.