My 66' is currently single pot master cylinder drum/drum setup. I'm in the middle of replacing all of my hardline and figured it was a good time to make the jump to a dual pot master cylinder. I have one from a drum/drum 68' mustang. Will it bolt right up and work or do I need to add things?

Also, what's typical plumbing for this swap? I've found a ton of info on the disc/drum swap but very little for keeping drum/drum in place. Could I just plumb the rear straight from the front pot, and plumb a T fitting into the front from the rear pot?

 

i know it was kind of a no no but i could not get the lines out of my proportioning valve other than the one that leads to the back brakes so i plugged off the rear brake line hole in proportioning valve and replaced hard line leading to the back brakes and never had a problem.... i used the dual pot M/C off of my 67 aka smokenchoke it was a direct swap into my 66 don't forget to rig up a new form of brake light since the old brake light used to be hooked up to a pressure sensor on the single pot..... i used the switch from a 72 and some scrap iron to mount it but you might want something a little better looking

 

Ray, Why don't you do the real upgrade and instead of a half A project go with a power disc brake upgrade using a 73-79 donor?



John

 

Would love to, but right now just want the truck on the road so I can use it. I'll do a disc swap after other priorities are taken care of. Still need to rebuild the fuel system, rebuild the electrical system, rebuild the cab floor, rebuild the bed floor, sort the lights out, source new wheels and tires.

 

I don't see why that wouldn't work. I'm terrible with this "custom" stuff. I typically strive to keep things as they were intended, but the brakes seem like a safety issue.

 

I don't think the Mustang MC will work for you.

I seem to remember that 67 was a unique year, so I think a 68-72 MC will work fine.

A MC only runs about $20 + core deposit, so less than $30 total Im guessing.

 

My MC is from a 68 with drum/drum setup. I guess I could just use it as a core, worst case.

 

1967/70 Mustang/Cougar with power DRUM brakes use the same master cylinder (C7ZZ-2140-G).

1967/72 Mustang/Cougar with power DISC brakes use a different master cylinder (C8ZZ-2140-A) than with power DRUM brakes.

1967/70 Mustang/Cougar with MANUAL drum brakes use a different master cylinder (C9AZ-2140-D) than with power drum or disc brakes.
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1967 F100/350 use one year only master cylinders, power brake boosters and brake pressure differential valves, 2WD different from 4WD.

The brake and clutch pedals, brake lamp switch, bracket under the dash the pedals suspend from, is also 1967 only.
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All 1940/66 trucks use the same brake lamp switch (C1AZ-13480-A [replaced 0A-13480] Motorcraft SW-24), located at the front of the master cylinder.

It's pressure activated by stepping on the pedal. It's also notorious for getting gummed up with dirty brake fluid.

Beginning 1967, the brake lamp switch attaches to a bracket on the brake pedal, but 1967's use a one year only switch and pedal.

 

So, according to paperwork, my 66 F100 should be fine to utilize the 68 mustang non-power non-booster drum/drum mustang MC - correct?

And it has built-in resisters for drum brakes front/rear, so all I have to do is hook like up and I'm good to go. Easy-peasy.

 

Dual master cylinders require a brake pressure differential valve aka proportioning valve.

You will also need to adapt a brake lamp switch that attaches to the pedal. See edited post #8.

 

Okay, thank you for the clarification. So something like this should solve all my issues?