Billy didn't really believe me, but this worked for me:
Find a 3/4" T-bar. I'll have to take some pics, but this is essentially an 18" (or longer) steel rod about 1.25" in diamter with a 3/4" socket head on it. Get a 3/4" extension (18" or 2 feet)and a 3/4 to 1/2 reducer OR a 3/4 19mm socket. Impact grade preferred.
With the T-bar, the 3/4 extension, the 3/4 to 1/2 reducer, and a 19mm socket, it took something around my body weight to break the bolt loose. I've done it twice now. Works like a charm. A regular ratchet or a swivel-head breaker flexes too much, and the more reducers and extensions you have just make things worse (each one flexes a few degrees, before you know it you have 90 degrees of rotation before you bite metal-on-metal). With this setup I've been able to break it with someone standing on the brakes (and in 5th).
The bolt is NOT reversed or LH thread. It's a normal RH bolt. Turn CCW to loosen.