I'm in the process of removing the brake booster and I'm having a hard time with the brake lines. I've loosened the one on the top next to the motor. I'm having a hard time with the top one next to the fender. With a flared nut wrench on the line and the same on the back nut I cant get it to budge. I'm wondering what size wrench does everyone use. Only size that's snug on it is a 12mm. But seems to want to round off the nut line. Any suggestions