After separating the rotor from the stator, next I needed to remove the stator from the aluminum backplate that holds it into place on the rotor assembly. It looked like the assembly was at least pressed in, but given that there were no fasteners, it wasn’t clear if it had adhesive, or if perhaps it was a shrink fit.
First, I tried heating up the assembly with a hot air gun, hoping that any adhesive would loosen up and possibly the stator itself would expand or break free. No dice.
Next, I tried using some PB blast off, followed by letting it sit overnight in the freezer, hoping that the aluminum would shrink more than the steel stator. Some hobby RC motor rewinders had used that technique on various motors successfully before. No dice.
Finally, I broke down and at Ben’s suggestion used a hack saw to just cut through the back housing, being careful not to go more than a scrape into the stator. Then with liberal application of force from a pair of heavy duty pliers, I was able to rip the back housing free of the stator.