Are you familiar with cottered cranks. If not, I suggest www.sheldonbrown.com for more info. If you do replace the crank, make sure to replace both cotter pins as well. If the crank is loose ( flops a bit while rotating) you might have to replace the cotters, about $5. You might have to do a bit of filing to get it to fit correctly though. Look at the bb, if it is at all rounded, i suggest getting a new bb and crank, square taper, octolink, isis, whatever. Cottered cranks, while beautiful, can be a bear to deal with.