From the pics it looks like you may be lucky. If you don't want to tear down and cut extra keyways just take them out, try driving straight down on one end and spin it out,both keys, you'll probably need to prick punch the area to raise some metal because the ballancer has spun,clean thoroughly add locktite,and install with a proper tool, forget the hammer and block of wood. Locktite the retainer bolt too. Hank