colo said '..garage mechanic..'.
How many of those have presses suitable for removing steering stems? Well..I don't, anyway. Maybe everyone else does.
'Sides, I wouldn't want to move the stem in MY bottom clamp for anything I didn't have to.
If you have a compressor, use your die grinder to cut the bottom bearing off. Don't have a die grinder? Heck...you NEED one..this is a good excuse (uh..REASON!) to buy a new tool. Be careful..you don't want to grind thru the stem! Don't get too rambunctious about it.
Or..use a vise (and some leather for protecting the metal of the clamp) and a crummy screwdriver, you can beat it off, too.
No vise? No compressor? Take it to a shop and have them remove it. You don't want to mess this up!
You can easily place the new bearing on the stem with a piece of 1 1/8" pipe. Thread the 'pound it' end, put a cap on it (better for pounding on) and a decent pounder (2 1/2# sledge works. Something like a 16oz claw hammer isn't going to do too good a job with the mass of the pipe)
FOLLOW THE SERVICE MANUAL for install of the unit. If you don't know how to install a tapered bearing, learn how before you do this! 'Tight' is not good. Wrench 'snug' isn't good, either!! While supporting it ROTATE the stem back and forth, tighten the spanner nut to a few inch pounds (hardly more than hand tight), then HOLDING THE STEM IN, loosen the spanner, retighten by hand.
Oh..before you do any of this (good I put this at the end, huh?) make sure you use some decent grease. The moly-di-sul junk that is 'multipurpose' is NOT what you want to use. Use a not good, not better, but BEST waterproof (say from a marine wheel bearing application) stuff you can get...say Hydrotex Parsyn 70. I haven't used belray, but have heard of good results with their marine application stuff. If it's not a sticky mess to clean up, YOU USED THE WRONG STUFF!
You won't believe the crap handling you've been dealing with! A new bottom bearing (replacing a snickity one) is GREAT!