Brakes and what PO did!

[Okanebm]

So here I am with brand new rotors, pads, and brake fluid, ready to spend an hour or two on my new ( to me ) 2000S! Well, this is what I've had to deal with. 2 different caliper bolts in drivers side rear, they are M12's but with 1.25 pitch. Still was able to torque them down to 63'lbs. my next find occured when I sheared the head off of the top caliper bolt on the passenger side front. Not too big of an issue, just time consuming. Copious amounts of pb blaster and two nuts driven onto the shaft later, was able to to remove the bolt, threads covered in.... Wait for it.... JB Weld!!! Ran a tap down and no joy. Mostly JB Weld and specks of metal came out. All the JB Weld was removed and with what metal was left for a M12, was able to get some grab, but not enough. By running the torque wrench in 10'lb increments was able to get to 40, but I knew would shear out the threads if I continued. So looking at going up the next size, but don't think M14 will fit through caliper to the hub, I can attempt weld/drill/tap, or heli-coil. Anyone had to deal with this? And know a good deal on heli-coil kits out there?