Brake line fitting size

[69SCSS]

My front disc line going from the prop valve to the T at the frame rail has a crack, and looking to replace it (it's leaking a drip of brake fluid each time I drive). What is the fitting size, 7/16-24? I found a couple replacement brake lines but since I need to keep the line on until I replace it (had to drive without it), I can't really bring it down LOL

My flare kit sucks and I need to replace it, otherwise I'd just fix it... but the line is really old and tweaked, so prob a good idea to replace it completely anyway.
Any help is appreciated.

[The Rocknrod]

Just FYI:
3/16" brake line flare nuts are 3/8"-24 - https://store.fedhillusa.com/316475m...elinenuts.aspx
5/16" lines are 1/2"-20 - https://store.fedhillusa.com/5168mmf...clinenuts.aspx
3/8" lines are 5/8"-18 - https://store.fedhillusa.com/38directory.aspx
Hope that helps.

[69SCSS]

Originally Posted by The Rocknrod

Just FYI:
3/16" brake line flare nuts are 3/8"-24 - https://store.fedhillusa.com/316475m...elinenuts.aspx
5/16" lines are 1/2"-20 - https://store.fedhillusa.com/5168mmf...clinenuts.aspx
3/8" lines are 5/8"-18 - https://store.fedhillusa.com/38directory.aspx
Hope that helps.

Cool thanks for the reply. So that line is 3/16" then, and the nut is a 3/8", so that's probably the correct one then?
https://www.summitracing.com/parts/a...8303/overview/

[mongocanfly]

just be aware that you can get the same size line with all different thread sizes..
heres a example...all 1/4 tube ..different nuts..https://www.summitracing.com/search?...%20flare%20nut
i used 3/16 and 1/4 in brake lines on my truck...and they all have the same size threaded inverted flare nuts...a good flaring tool is not a cheap investment,,but well worth the money...
i have the eastwood version...
i bought all my lines as premade 6ft lines from oreillys..and then cut to length and reflared

[The Rocknrod]

Sorry - mongocanfly is correct! you "may" have different sizes depending upon who built the system. The only way to tell for sure is to size them yourself. I just gave the "normal" sizes for the lines at large.
For instance I have 3/16" lines coming off the front and rear ports of my master cylinder, neither of the ports are 3/8"-24. They make nuts for 3/16" lines (or what have you) in various sizes.

[69SCSS]

Thanks guys, measured my line up and it's 3/16" OD, so that solves that, and the fitting measures 3/8" at the hex and slightly above at the threads, so most likely 3/8-24. Going to pick up this line from Summit and it should do the job.

https://www.summitracing.com/parts/aaf-all48302

[jbarron]

These Parker inverted flare gaskets work great for lines that just won't seal.

https://www.grainger.com/product/5WR...g!540946298555!

[The Rocknrod]

That's interesting. I've never heard of those. Have you had luck with them?

[mongocanfly]

I've never seen those either...but havnt had issues with inverts leaking either..

[69SCSS]

Originally Posted by jbarron

These Parker inverted flare gaskets work great for lines that just won't seal.

https://www.grainger.com/product/5WR...g!540946298555!

Thank you for recommending these, they did the trick! Sealed up nice and clean now.
There might have been a burr or scratch inside the Prop Valve that was not allowing it to seal correctly, because I could not get it to seal completely until I used this. Thanks again, I can drive my truck now!

[45ACP]

I'm not sure about a few things like if these lines were original or not, but the last 1972 C10 that I changed brakes on, both rear and the right front hard line inverted flare nuts were 3/8 -24, but the left front was 7/16 -24. The flex brake hoses that came with the kit were all 3/8-24 so I used a
Dorman 785-434 line adapter to easily make things work without needing to re-flare any hard lines.
https://www.summitracing.com/parts/rnb-785-434