I'm re-doing the frt brake lines on my Maverick and the problem that's been giving me fits is that the factory 3/16" inverted flair nuts on the car have the same thread size as a 1/4" line fitting. I've hit every parts store around along with fitting suppy stores and came up dry. The current 3/16" fittings you get are too small on the thread end so an adapter is all anyone could suggest. Well since my objective with this car is to get rid of all of the hack work I did as a teen...I was totally against adapters. I went back to the local NAPA for one more shot and talked to one of the old timers and told him my problem. He walked to the back and hands me a short piece of 3/16" brake line that they stock that had 2 different size nuts on it. One of the fittings is what I needed...3/16" to 1/4" just like what came on my frt brake lines. And at $2.99 each, that's about what the fittings run mail order if you can find them. If you run into needing one of these fittings, the NAPA part number for the line is #813-1154.
I'm guessing more places actually have oddball fittings...it's hard to find someone who knows how to find them. I'm plagued with young kids that look at me like I'm speaking another language when I ask for something at a parts store. And I always try to look up the part first so I know exactly what it's called at that store.
Bingo! They usually let me go back to their brake line selection and just look for what I need lol...I just recently swapped to the Ranger master cylinder, which has metric threads, and had to swap one fitting out on each end and reflare them to standard flares...they looked at me like a dog watching TV when I tried to explain what I needed lol. I finally just went back there and got what I needed...and that was that.