FYI, there isn't a single bubble flare on any 140 Volvo brake line. They only used inverted flares. Bubble flares with UNF fittings are used on some earlier Volvos and then starting in again in 1975 with the 240/260 Volvos, but those use metric threaded fittings.

In the past, I have seen incorrect brake flares seal before, but only because excessive force was used.

You can in fact source inverted flare male and female fittings to make your own lines. They won't look the same but they will work and seal with inverted flares.

If you are lucky, you will have a "mom and pop" owned auto parts store that has a decent supply of 3/16" male and female fittings. If you don't, your local Napa Auto store should be able to supply them.

I am well supplied with steel and Ni-Copp(Nickel and Copper) bulk brake line and the tools to make inverted flares as well as bubble flares. Whenever possible, I reuse the original tube nuts as exact copies of the originals aren't available.

Another FYI, If you don't want to buy an inverted flaring tool kit, AutoZone and I think Oreilly's auto parts have a tool rental program. You usually have to buy the tool and you are allowed to return for a full refund if returned undamaged and I'm pretty sure they have an inverted brake flaring tool set.

--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com