10-20-2013, 07:22 AM
My Maguna for a long time had limited range of motion of his arm on one side. Then his shoulder popped out as you described. That shoulder piece that goes on between the clamp and the arm had a high spot on the inside on the bottom along the seam on the arm side. It prevented the top of the arm from going in as far as it needed to in order to snap into that c clamp. I carefully sanded it down and tried the fit, sanded some more until the arm would seat back into that clamp properly. Take a close look at how the upper arm is fitting into the shoulder piece and compare it to the other side. I bet you will find the problem is something similar.