Hey Jeepster,
I don't know how far you got with your Model 20 but...
First thing to do is remove the hub from the shaft. You'll need a puller to seperate it after removing the big nut.
You need to remove the little nuts (maybe nuts and bolts - I don't remember) that are around the axle shaft. These hold the brake backing plate on to the rear end housing. There is a dust seal there to remove (it's the same shape as the housing flange (like a D shape) metal plate with the seal vulcanized onto it. Then the shaft will pull out of the housing (usually by hand). You'll need to get new bearings pressed onto your new shafts AND - You might need to have the brake backing plates in place BEFORE pressing the bearings. Be sure to check out the placement of these parts because I'm running on 20 plus years of memory!! Best of luck - John
