In a used bike I am refurbishing, one steel pedal shaft has seized in the alloy crank arm. I can turn it about 1/4 turn, then no more. Rather than wreck it, I'll likely ignore it (although it would be nice to be able to install SPDs). LBS tells me that further efforts at removal will automatically trash the arm. I am curious, though: does anybody have any tips for such situations aside from liberal amounts of PBlaster and some heat? When these seize, are the crank threads automatically shot?