Bicycle Mechanics - Seized Pedal Shaft in Crank Arm

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?

If it's turning a quarter turn, it's not seized in my book. I'd keep working it and lubing it. It will come out.

Yeah, you're pretty likely to peel the threads out of the crankarm, as that aluminum is really soft. The LBS can install a helicoil to repair it.

The damage is probaly done, so if it were me, I would try to get it out. You may be able to chase the threads in the crank and make it work.

Not to insult your intelligence, but are you sure you are turning it the right way? Left side crank has left handed threads.

The most important part of the post, as always, is left out.

Which SIDE is the crank on? Left or right? San Resho is correct in asking which way you are turning the pedal spindle to remove it. If you have been able to turn it clockwise a quarter turn and it is the left hand pedal, all you have done is tighten it even more. If that is so, undo it the other way!!!

Even if you have tightened it more, you won't have damaged the threads -- that is more likely if you cross-thread into cranks, and believe me, if the threads are damaged as the LBS implies, you would be turning that pedal spindle freely until the cows come home.

The most important part of the post, as always, is left out.

Which SIDE is the crank on? Left or right? San Resho is correct in asking which way you are turning the pedal spindle to remove it. If you have been able to turn it clockwise a quarter turn and it is the left hand pedal, all you have done is tighten it even more. If that is so, undo it the other way!!!

Even if you have tightened it more, you won't have damaged the threads -- that is more likely if you cross-thread into cranks, and believe me, if the threads are damaged as the LBS implies, you would be turning that pedal spindle freely until the cows come home.

The left hand pedal loosens when turned clockwise. Have a friend pour boiling water over the crank while you push on your cheater bar. The aluminum will expand more than the steel, and boiling water is not hot enough to upset the metallurgy of the crank.