You will need a hydraulic press, bearing splitter, a big Hammer and a large 3/4-1" chisel.
Place the axle bearing collar upon something solid; I use an anvil. Take the chisel and put it on the collar in line with the axle. Strike the chisel several times. This distorts the collar. You will need to have at least 1/32 of a mark left from the chisel in the collar.
From there you need install the bearing splitter and place the axle into the press. Start pressing the bearing which will in turn press the collar off as well.
To reinstall press the bearing on first and then the collar. Make sure you put the radius side of the collar away from the bearing as it is designed to not damage the seal during the installation of the axle into the housing.
If it were the old two piece welded axles, the same replacement process will work. I had to grind down a few of the spot/plug welds in the splice but the bearing will fit over it.
If you do not have any of the tools I mention above, then an automotive machine shop will be your best bet.
Randy - RPM