1999 D2, but that's largely irrelevant.
The flats on one of my head bolts have rounded off, so it's at full torque and I can't loosen it. Of course it's one of the bolts at the bottom of a valley, so I can't get a grinder or Dremel down there. I have the other bolts still torqued down to try and reduce the tension on it, but I'm not having any luck getting it to move.
I have drilled into the center of the bolt but I don't want to run the risk of going astray and damaging the head. I don't have any faith that an E-Z Out will be able to handle the necessary torque. Does anyone have any suggestions?

 

Have you try a 5/8 12 point socket?

 

Of course. Two different ones. And a 12-point 16mm socket along with a regular 6-point. Two of them split. And there's not enough head left to be able to get a socket onto it any more.

 

Craftsman makes a damages bolt/nut remover. You hammer it on the bolt head. It will cut into the damaged head, and continue to dig in as you apply torque.


Craftsman.com

 

Hmmm. I'll take a look at those. There's almost nothing left of the head though. I'm at the point where I think I'll just have to use a pinpoint grinder on my Dremel to chew away enough of the head that it collapses.

 

https://www.jbtoolsales.com/irwin-53...N1fxoCGtvw_wcB

You need something like these. I have some from Snap-on and they work great

 

I've had great success with those sockets.

Worst comes to worst, get your self a nice set of cobalt drill bits. Start small and keep drilling until the bolt head comes off.

 

Well, I managed to get the bolt out, after much careful grinding and drilling and aiming with a narrow cold chisel.
The two sockets in the background are the ones that split when I was first trying to remove it, when the bolt was still mostly intact.
Damage to the head itself is minimal, thankfully.