I am replacing the serpentine belt and tensioner on a 1999 Ford Taurus with the 3.0 Duratec V6. The tensioner has slacked up enough to allow the tensioner pulley to move toward the passenger side of the engine compartment, making it quite difficult to remove the bolt that holds the tensioner to the timing cover. So I resolved to remove the pulley first....But I could not access the 15 mm head with a socket wrench, pull handle, or wrench/ratchet wrench, so I created this innovative tool. 
Pictured it is fitted with a 7/32 Allen head socket (yes that is the correct size), the other attachment was a 3/8 drive 15mm socket for the tensioner pulley bolt.

Pictured it is fitted with a 7/32 Allen head socket (yes that is the correct size), the other attachment was a 3/8 drive 15mm socket for the tensioner pulley bolt.