What? Why would you install an old bearing if you are going through replacing the races/bearings with new... HUH??? Hog it out and reuse it? Didn't realize hand holding was taken to that level. I said to set it up for pinion depth.... NOTHING MORE.
It's a set up tool, nothing more. Ever seen a guy try to set up pinion depth with the pinion cockeyed? I have and it was fun to watch. My suggestion is nothing more than a cheap and easy way to basically idiot proof the situation. Makes sure the pinion is centered up in the bore at the front side. Slide it on, secure it with a spring clamp, no flopping at the front of the bore.
Carry on.
