How to remove a bolt with a broken head?

Don't use a "bolt extractor" if you can just drill thru and use a thru bolt with nut, which I b'lieve you can do.

Yep... but my question is front or rear... and what model of car? Because it makes a difference in which way has to be done!

Mercedes 300E, 103 Motoe

Spray it with plenty of WD40 and let it work in overnight. If there is enough to get a grip on, which there usually isn't, you can try vice grips. Also, heating it with a torch, if possible, can be a big help.

Next, would be a screw extractor. This is a tapered spiral device available at auto parts stores. You drill a hole in the remaining bolt, the screw extractor goes in and you turn it, which tightens it into the hole and turns out the old bolt.

mmm ... thinking hard here ... yep! ya got ta fix yer haid first. So call 911 and have them come and fix your poor broken head. Then working on this bolt will be a lot easier.

mcbrue thinkingly under the bridge in the trailer down by the river

put a nut on top of it and tack the inside of the nut to the broken shaft of the bolt. Fill the nut with weld. Let cool. Remove with socket or wrench.

of course, you have to have a welder to do this.