Another trick if you have no help is putting the breaker bar with the correct socket on the bolt, then prop the breaker bar against the cement, and turn the key. That'll loosen it realy quick... But I'm not sure you want to try it without the head and all that in place...
And an electric impact at harbor freight is 49.99(not cordless, dont get cordless)
Electric Impact Wrench - 1/2"
And an electric impact at harbor freight is 49.99(not cordless, dont get cordless)
Electric Impact Wrench - 1/2"