[Roadsters] '70 2000 Wheel Cylinder hard line nut size.

[Ronnie Day]

Don't I need a 10 mm flare nut wrench for the brake line nut on the rear
brake wheel cylinder on a '70 2000 roadster? I'm pretty sure that's what I
need, but I've got a 10 mm (too small, or just won't go on) and an 11 mm
(too large). Neither work. Looks like someone in the past buggered the nut
flats royally. Figured I'd check before  go after it (carefully) with vice
grips. Both side are soaking in PB Blaster.

TIA,
Ron