Adding to what Red Dave said. Check the crank and make sure there are no deep grooves or it seems excessively worn. You can get a standard seal if everything looks good, or you might need to get one with a Speedi Sleeve if the crank is worn.
As for getting them off, dad and I finally invested in a good bearing splitter w/puller. They can still be hard to get off, but that it makes it much easier.