I have a 91 300se. I need to get the old alternator out and put the new one I bought in. However, I am having troubles taking one bolt off of it. I have tried everything and the bolt is almost stripped. It seems to be smaller the a 16mm but larger then a 15mm socket. Does anyone have any ideas on what size socket I can use in order to get this last bolt out. It is the only bolt that connects it to the engine.