So I need to replace both front hard lines on the calipers, plus the rear axle brake lines on my '69 144s.

I don't mind using steel lines, so I bought my 12", 20" and 40" lengths at the local chain parts stores.

They offered me "European" or "American" types. I guess this refers to Metric or SAE thread types.

Frankly the American variey fit better, but seemed a bit loose until completely "home" against the flare. So, I can't be sure it won't leak.

The European style, I couldn't even get threaded onto my caliper, new rear flex hose, nor a female caliper conector.

So is the SAE (American) style the real fit?

A read an archived post which stated the lines are 3/8" - 24UNF.

That posed two problems:

1) the lines are 3/16"

2) none of the parts store use 24 UNF in their item identifications.