edit: i think i broke a heli-coil. What size are the bleed bolts in the FD?

So when i was bleeding my brakes i over tightened a bolt and found i had broken a small metal coil which was wound around the thread. Brake fluid came squirting out when i put the bolt in w/out the coil, or tried a fresh bolt.
I assume the previous owner just screwed it up and now the coil is necessary to keep the thread intact.
Where would i get a new one? What is it called?

 

A: 8mm x 1.0mm, heli-coil insert