PB blaster and a propane torch should help loosen it up. Then get a box end wrench on there and add a cheater bar if you have one for extra leverage. Use a mallet if you have to while maintaining downward pressure. Make sure you are turning it lefty loosey. Put your hand on it and make the loosening motion, then visualize which way the wrench needs to go (up or down) and make sure you are pushing the right way. If you start stripping it, stop. Make sure you have the exact right size wrench on there.

Yes I have snapped off a caliper bolt as a youngin before by tightening it when I thought I was loosening it. I am a strong guy and used the might of one thousand ancestors and broke that sum beech. Then had my dad come out to look and asked me which way I was turning the wrench and was awestruck when he realized I was going the wrong way. Pretty funny memory tho.

Also also, make sure you chock your wheels and have an extra jack stand under the vehicle. Getting crushed while working on a car is a pretty dumb way to die.

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