You mis-read. I didn't say the rubber boot had anything to do with capturing the rod (just keeps dust out). On manual brake rods, a stiff rubber bushing fits on a groove at the end of the rod. When you insert the bushing into the MC piston, the bushing locks it in the piston. People say that manual MC's have an internal step in the piston's hole to help grab the bushing (I never checked). My point is that in the "power MC" I used, the bushing still locked in very tight, so "should work".
