Prior to installing my side dimming mirrors, I disconnected the negative on my battery. When I went to reinstall, the instructions I was reading said to torque it to 66lbs and while I was tightening, the bolt completely sheered off. I know nut is 10mm, but I'm not sure what I need to look for when I go to the auto store. My local Subaru parts dept couldn't find a part number and even if they did, they'd likely have to order it. Any help would be greatly appreciated as I'm not going anywhere anytime soon without this fixed.
