740 700 rear brake line thread size?

All,

I'm trying to find out what thread the 700 series rear brake line size is at the body to flexible line junction. This is the junction that is in the rear fenderwell with a bolt that holds the hard line as it transitions into a soft line.

The car is an '85 745td, though I'm guessing that many years are the same.

Anybody know this brake line thread size? Either the hard line male thread size or the flexible line female thread size?

thanks,
simon