aci body leg loose

anyone know how to strip down legs on aci bodies, i have a right leg that is very slack, its the top part of the thigh part that revolves around the top ball joint, its quite slack, the left leg is fine, i managed to get the knee joint out to look into the retaining slot which is a one piece mold by the look of it, and can find no way to tighten it or take up the slack, maybe i need to take off the ball joint, this looks tricky as it looks like it has a tension spring in there