After rebuilding and replacing the brushes in more of these starters than I can count, I developed a trick which works for me. You need two thin flat pieces of sheet metal about 3/4” wide and 4”-5” long. Install two brushes and use the metal strip to hold them in place with one hand. Install the other two brushes and hold them in place with the other strip. Sorry, I don’t know how to tell you how to hold the two strips with one hand, while not covering the bearing hole, it takes practice. Carefully slide the bushing cap onto the armature, not letting the brushes slip out. Again, this takes practice. Once the cap slides down snugly, remove the metal strips, and rotate the cap into the correct position, there is a notch on the cap. Bolt together loosely and make sure the armature turns very smoothly. Tighten bolts, being careful not to over tighten and crack the cap. This works for me, but you might want an assistant, which will make it a little easier. It can be a very frustrating until you learn how to do it, so patience is a virtue in this case. I’ll bet it will take at least 5 trys before you get it. Good luck.