Adding dual master with power drum brakes

[BJRVentport2]

Has anyone replaced the single bowl master cylinder with a dual master cylinder, and kept the Midland power booster? If so how did you do it, what master cylinder, and how did it work?

[paul2748]

Typically, when using a dual master just the front brakes are are plumbed into the booster as the front brakes do most of the work. I don't have any info on the unit to use.

[new birder]

I just recently bought a '56 Bird with the original braking system, drums with the single master cylinder. I'm going to change my master to a '67 Ford Mustang non power brake cylinder. I Googled this question to the internet in general & the answer was the Mustang unit has the same bolt pattern as the original Bird master cylinder. I plan to plumb 1 port from the master to the union where the power brake line & the old brake light switch connect with the front brake hydraulic line. The other line on that union goes to the rear brakes & I'll disconnect it from the union & connect it to the 2nd port on the Mustang master. This will still give me power brakes on the front using the original '56 power brake system which had been recently rebuilt by the previous owner. I'm a hot rodder & would've probably switched the front to power disc, but this car had had the entire brake system rebuilt with new shoes, hoses, cylinders, etc. & brakes very good as is. But I like the safety of the dual master system so I'm switching to the Mustang. It also is small in size so it'll fit well. I have a '51 Buick woodie wagon that I used a '67 Cadillac non power master on & it's done very well for nearly 40 years now. A little engineering to locate it in the original location was all it took.

[55blacktie]

You could get a 1967 Cadillac without power brakes?

[BJRVentport2]

I just replaced my single master with a dual from a drum drum 67 Mustang. I did remove the booster as I think it needs a rebuild. But it would be easy to plumb it for the front brakes only. My car stops great, but the pedal effort is pretty high. Maybe this winter I will put a disc brake kit in it.

[BJRVentport2]

After driving my Bird with the new Mustang dual master I have found that it gets very hot. The dual master is a lot closer to the exhaust manifold that the stock one, and it gets so hot you don't want to touch it. Also the Midland brake booster mounted in it's stock location but is not hooked up yet, gets so hot you can't touch the band holding the diaphragm together. Any suggestions on how to remedy this? Is this normal?

[Jimntempe]

After driving my Bird with the new Mustang dual master I have found that it gets very hot. The dual master is a lot closer to the exhaust manifold that the stock one, and it gets so hot you don't want to touch it. Also the Midland brake booster mounted in it's stock location but is not hooked up yet, gets so hot you can't touch the band holding the diaphragm together. Any suggestions on how to remedy this? Is this normal?

It depends on how hot is hot. The engine when warmed up is a chunk of metal 180 to 230 degrees so just about anything under the hood on a hot day in the city is going to get up to a temperature too hot to touch for long. The exhaust manifolds will be running probably 300+ degrees right by the master and booster so I'd be surprised if they were not pretty hot when things are "normal". If your timing is way off, or the carb too lean that could make it even hotter than normal. I over advanced my timing and it made the engine run way hotter than normal and I had to stop on the side of the road to retard it or I would not have made it home. I talked with someone with a 57 at a car show who had added a dual MC and he had the same concerns you do. He put on some shields and insulation and still thought his MC and lines were getting too hot. I've still got the original single MC and mine has not seemed too hot to me.

[BJRVentport2]

I made a heat shield for the master cylinder and the power brake unit. I also changed the timing with about 5 more degrees of advance. I put a heat gun on the exhaust manifold next to the master cylinder and it read 345 degrees. The master cylinder read 115 degrees, and I could put my hand on it with no pain. So Win Win.