I am replacing the serpentine belt on my Mustang and see what appears to be the belt tensioner but can't see you you can release the tension to install a new alternator. Most tensioners have a place where you can place a socket to release tension while putting on the belt but I can't seem to find it. The larger torx bolt in the center is not moving so I have to assume it is just to bolt the whole tensioner to the car. Help is much appreciated.