I think with the proper crimping tool in my press, this would have been easy - not sure what that tool would be, but it is very similar to the way Lionel installed the flanged axle bearings in 600 series diesel side frames.
I was the back bidder on a crimping tool set designed to do the brush holders on a #50 gang car brush plate. An important feature was a round bar that went into the brush holder to prevent any of the metal being displaced by the crimp from entering the brush well.
That brush plate is a little different in that the terminals are underneath the plastic plate, right next to the openings for the brushes.
Some folks create a little solder bridge between the brush holder and the solder terminal to resolve the issue you describe.
