The annual has been completed and 45P flown. The brake chatter is gone but time will tell if the problem is completely cured.
Here’s the deal. The old pressure plate on the left main brake was removed and examined. The two ears that contain the holes for the guide pins were noticeably bent or warped. This would not let the pressure plate slide smoothly over the guide pins (anchor bolts). The original pressure plate was replaced with a new pressure plate. It is note worthy that the new pressure plate is thicker metal than the original pressure plate. This will make the ears less likely to bend or warp. The pressure plate on the right main brake had a very slight warping but not nearly a much as the left main brake. I’ll replace that pressure plate later.
Miller 45P