The axle has to be removed to replace the outer boot unless there's a VW style split boot kit available. But these generally don't last long at all on outer CV's. There's a circlip (sp?) around the shaft that has to be removed to slide the CV joint off. Maybe some heat would help?? My Haynes says to put glue on the axle splines when installing the axle. Don't know why but this may be the problem. When I replaced my boots I omitted the glue. Hope that doesn't cause a problem later on. There's a really thorough replacement explanation a few days back.