Go to home depot and buy a piece of steel pipe which slides over the shaft and rests on the inner bearing race.
Freeze the pinion overnight, heat the bearing up in the oven for 5 minutes @ 350*.
Pull the pinion out of the freezer and throw some lube on the shaft o.d.
Grab the bearing with some pliers and put it on the pinion.
Finally, use the pipe you just bought and carefully beat the ****nit out of it…making sure you only contact the inner bearing race.