The obvious answer is to try different wrenches on it till you find the correct one.
Do you seriously not have a few to try?!?
You need a 15 mm regular wrench.
It will be a 14 or 17 mm wrench.
The T60 is the size needed to remove caliper bracket.
What size line wrench for a 2005 freestar
45t
use an Allen wrench not a socket or open or box wrench.
You need a 3/8 Allen Wrench
18 mm I think.
19 mm
15mm
14 mm