Originally Posted by Poguemahone
No kidding. I once had one the little @#$% mushroom out on me; I had to take it out with a drill. What a PITA. Since I've gotten the Park tool, I wonder why I ever used anything else. Like a Var 30 fixed cup remover, it's a tool designed for one purpose, and boy, does it do it well. I also always spray some penetrating oil in a cotter pin and let it sit for awhile before I attempt removal.
After removing a bunch of cotters, I've found the key is to get a rigid support under the crank before one delivers the blow to the cotter. I have a big cedar block that I've embedded a length of steel pipe into so that is sticks up vertically. I then position the crank arm horizontally with the crank arm resting firmly on the end of the steel pipe. Make sure the pipe is lined up directly under the cotter itself. The cotter is now pointing straight up. I now rest a crowbar handle sideways on top of end of the cotter protruding from the top of the crank. I strike the crowbar directly above the cotter with my biggest claw hammer. Don't be bashful. Give it a healthy blow. Cotter lands inside the pipe. I haven't found a cotter yet that will resist more than 2 strikes. Using the crowbar keeps from damaging the cotter and allows it to be reused.