Danger: Single master cylinder on board!!!

Vinyl66

Member
Mar 21, 2004
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Friday I was cruising down the interstate and as I got onto the exit ramp I proceeded to push my brake pedal slowly to the floor and was still going!
So I started pumping them and the brakes caught a little each time to slow me down some and then I downshifted (automatic) to slow even more. Luckily there was no one in front of me and I was able to keep going. I could have easliy hurt Vinyl66 or myself.
I was able to pull into a parking lot (very slowly) and check the problem. The rear brake line was broken inside the fitting that screws into the brake cylinder. Holy crap it was scary driving with no brakes!! No wonder dual master cylinders were federally mandated in 1967. That is just plain dangerous with a single cylinder.

So anyway, I want a dual master cylinder now. Is it didfficult to retrofit a '67 dual master cylinder to my '66. Who has done this swap? What parts do I need? I will probably go to disc brakes in front at a later time also if that changes anything.
 
I don't know if the regular 67 MC will support disc brakes, unless it is already set up for front discs.

When I converted to 4 wheel discs from 4 wheel drums, I had to replace the MC with one which came standard on 96-98 Cobras (I think). Before I swapped the MC, I drove for awhile with my stock MC, and when I installed the new MC, the improved braking effectiveness was noticeable.
 
Nice write up...

You can run the dual master for disc brakes as well. This works with the drums you have but makes converting to disc in front easier, later. The front calipers will need more fluid. I don't think that dual bowl drum master is sufficient for discs if you are eventually going that way...
 
That is a great write up and exactly what I need. Pics are always good :D
I will be doing this swap very soon and I would suggest others with the single cylinder fruit jar do the same. I was actually lucky.
 
my brakes went out in my '66 as well, that really sucked, but thankfully i figured it out before the huge hill i was about to go down. the swap is simple, and if anyone hasn't done it yet, they should. doesn't cost too much and the piece of mind is worth it.