not sure if breaker bar by itself will do it. I'm assuming you sprayed it with something like PB Blaster before hand.

A pipe worked fine with the car on the ground - just need a longer arm to apply more moment to it.

I used a screwdriver, but it drove the screwdriver part up into the handle. I went the hardware store and got a 6" chisel that worked great for opening up the existing one, and closing the new one.