While attempting to get rid of my belt squeals, the mechanic discovered that the tensioner bolt was stripped out and missing. Problem is I have no idea where to get this bolt. BMW dealership wants me to pay 800.00 to get the entire tensioner assembly vs. just get the bolt. Any idea where I can get this bolt? Tried all kinds of part places online and nothing so far. Mechanic suggested having it custom made for200-300 dollars. Help!!