Old Buick Brake Line Fitting Sizes...?

I am new to the antique domestic car scene, so please excuse if this is a "duh" question. I did try to search but did not find an answer.

I am going to re-do all of the brake lines on my 1957 Buick Super (all hard lines and rubber hoses), while at the same time converting the front drums to disc brakes. I am going to use a dual circuit universal 7" master cylinder with special adapter plate and a disc/drum proportioning valve. Rear drum brakes are freshly rebuilt to factory Buick specs.

My question is, can anyone shed light on what kind of flare fittings are used:

1. On the Buick originally

2. On the new universal master cylinder and proportioning valve

I am guessing 3/8-24 inverted flare with 3/16 tubing, but I may be wrong....any insight would be appreciated. Thank you.

One of us needs to go out and look at them. You are closer than we are.

Brake lines and fittings have been standardised since before your Buick was built, they should be the same as the ones you buy in any parts store.

True!

I did some leg work and the lines that go to the wheel drum brakes are 3/16" tubing with fittings that are 3/8-24 SAE Inverted flare... just as I suspected!

The fat one coming out of the old brake master cylinder is 1/4" tubing with 7/16-20 Inverted flare

For a side note:

Vintage japanese cars use M10x1.0 SAE Inverted flare brake lines.

I hope that someone in the future finds this post helpful.

Now back to work!

Sometimes most G,M. cars parts can be interchanged. The Filling Station sells brakes conversions kit and may be able to at least guide you. Google The Filling Station. Good Luck