Thus, I grabbed the big gun(s): Proper socket and cut off the wires... I needed the hinged wrench, which allowed me to apply a big lever in an inward angle, as the master brake cylinder would be in the way otherwise. Oh, and I applied plenty of proper penetrant spray first. Btw.: Using a 22mm spanner was not possible, as there is a bolt holding the cat onto the exhaust-manifold, which is in the way and would prevent any turn with a spanner.