I have a harbor freight large separator. (although I can't speak for its quality, I have yet to use it.)
my large separator
They also have a smaller one that looks interesting. You might be able to use it with a steering wheel puller
by the looks. With long bolts (assuming the 2 holes are threaded) or some all thread rod you could rig it to
pull over any length.
These are normally used in a press with a couple of heavy plates bridging the table to catch the edges
of the separator. If you make those plates its a good idea to make them with a 2" or so hole/notch
to get more bite while cleating the shaft the bearings are on.
Removing axle bearings: aftre the ball bearing retainers fall apart its common for the ball to come out and
the outer race falls out making it difficult/impossible to use a puller. Use a 4" grinder to cut almost thru the
bearing coller and then break it with a chisel, being careful to not mar the surface of the axle. then it will
about fall off.
If the old bearing coller slips or is easy to remove, it's likely the axle got too hot and shrank, making it scrap,
very dangerous to use as the new bearing and retainer will not grip it properly.