Guys on my lathe the pin that locks the back gear to the spindle pulley keeps popping out.Looking at the diagram there is a spring and a plunger that keeps the pin in position.I suspect that maybe the spring is broken cause when I move the pin in/out I don't feel any resistance.How can I remove the back gear pin,will I have to remove the back gear from the spindle to make repairs or can it be fix in place?Thanks for any advice----kroll