I use my 450lbs impact driver. But since it seems you don't have one there is a "junkyard mechanic" way. Like I said this is up to you if you want to do it. Get your breaker bar/socket and brace the bar some where that it doesn't move. Once you do this, now like I said this is up to you, "blip" the starter. The starter is strong enough to break the bolt loose. If you don't want to do this, put everything back(hoping the car is still running) and go to your closest tool rental place. If you are nice to these guys, they will help you. Ask them if you can borrow their impact gun to break loose the crank pulley bolt. Alot will since they use pneumatics for their maintenance and repairs for their vehicle. Once you break the bolt loose, reverse the gun so it puts the nut back BUT let it impact just a little so when you get home, you can break it loose and change your belt and water pump.