Y pipe bolts

I'm replacing the exhaust on a 03 Escape. I'm replacing the Y pipe back. I'm stuck here because i can't figure out what size the nuts on the Y pipe studs are. If i use a 14mm socket it's loose, if i try a 13mm socket it won't fit on it. Same with a 1/2 or 9/16 socket. Anyone replace the exhaust on one before & know what size socket i need?

It is suppose to be 14mm, but they rust off an outer layer and become smaller with age. I had to take a sawzall and cut them off on my 02 when I couldn't get visegrips, 24 hour soaking with a good penetrating oil and heat from a torch to work.

It is suppose to be 14mm, but they rust off an outer layer and become smaller with age. I had to take a sawzall and cut them off on my 02 when I couldn't get visegrips, 24 hour soaking with a good penetrating oil and heat from a torch to work.
Napa or Sears sell damaged nut removers. You will need new nuts when done and the stud may break. Soak good with PB blaster.