I've used that method to cut rusted nuts off of bolts. Usually the threads of the bolt were undamaged and the bolts could be reused, but if overheated, the bolt would have a gouge in it. I'd be hesitant to use that method on the sleeve. If you damaged the bracket you'd be trying to find a replacement. Using a ball joint press is a much safer method.
My guess is that you have never tried to cut cast iron with a torch. It doesn't cut well even if you crank it way up past the level needed for steel.
