we had the same issue; After soaking in de-greaser I soaked it in vinegar essence for a few days and lots of WD40 for another day. The final job did a 10 ton hydraulic bearing puller like what you find at ebay "10 Ton Hydraulic Gear Puller and Bearing Jaw Separator Set Professional Kit" I put a SS screw (Allen hread) in the bottom of the Aluminum shaft to protect the thread and then pushed the aluminum piece out of the hollow steel shaft. It has to come out otherwise you can't get the bearing off. -- Michael & Robyn