sysmg

I am planning to upgrade my 66 Starfire to front discs and a dual master. There are plenty of posts with lots of details about the disc conversion using the scarebird kit. However not much about upgrading the Master to dual with a combo valve. I have most of the info, but need more info about the brake lines.

I am trying to figure out what brake lines to buy and what size fittings they need.

I can easily check what sized open end wrench fits on my existing fittings, but how do I tell if the fitting is 3/8-24, 7/16-24 or 1/2-20? The line from the master to the 3-1 tee uses a 7/16" wrench on both sides (what is the fitting size? 3/8x24 or 7/16-24?). The line from the tee to the rear brakes also uses a 7/16" wrench (is that the same fitting size?). The lines from the tee to the two front wheels each use a 3/8" wrench (what size is that fitting?).

Here are the other parts I believe I need:
- Centric 13062074 - dual master cylinder for front disc brakes on 1967 Olds Delta 88, this has 1/2-20 outputs for both front and rears.
- MPBrakes VL3360K - Universal Combo Valve Disc/Drum kit (inlets: front 1/2-20 and rear 7/16-24. - Outlets 2 @ front 3/8-24 <need to plug one> and rear 9/16-18.)
- Booster Dewey shorter Delco Morraine Power Booster Rod for the new master
- Two short brake lines to go from dual master to combo valve. What fittings do I need? Do I need to use any adapter(s)?
- One brake line from combo valve front output to existing tee (plug off output to rear brakes). What size fittings? What size plug?
- One brake line from combo valve rear output to a coupler to the existing line to the rear brakes. What size fittings? What size coupler?

Any additional info or corrections would be much appreciated.

Wilsonson1

Hey I also have a 66 Starfire and want to know if you ever got the conversion completed? And if so what master, booster, and proportional value did you use? I saw the response that the 66 Cadillac master cylinder would just bolt up to the factory booster. Were you able to confirm that?

sysmg

I took another route. I've obtained disk brakes from a 67 Delmont and am planning that installation now.

But I did a lot of research (just never implemented it) for the hydraulics for a scarebird kit.

I was planning to use a 67-68 Oldsmobile Master Centric 13062074. This was available at Rock Auto a few months ago. If you get a Master make sure the lines come out on the passenger side. No room for them on the drivers side. You can also reach out to the brake supplier for a recommendation.

According to my brake booster rebuilder (boosterdewey) that master should work with my Delco brake booster with a shorter rod. I bought that for a few dollars.

I was planning to use the following combination valve VL3360K Universial Combo Valve Disc/Drum https://www.mpbrakes.com/accessories...A6C259620BE1AC

You will need a plug to seal up the tee fitting output to the rear brakes. You will also need a female to female adapter to connect to the existing rear brake line. Then you will need to have a bunch of brake lines made up to connect everything.