Thread: '30 Ford Brake/Clutch Pedal?

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The pedal actuation ratio is very important. You can't buy any pedal assembly, put a vacuum booster on it, and expect it to work properly. A lot of folks have posted problems, getting the correct combination of pedal ratio to work the particular master cylinder and brakes that they are using.

I bought a body/chassis, with a 7" single diaphragm booster, 3.8/1 pedal ratio and 1" master cylinder, but found the braking unimpressive with my high-dollar Wilwood disc brakes. A 7" dual diaphragm was better, but still not as powerful as I wanted.

I called Wilwood and got a recommendation for a minimum 8" dual diaphragm booster, to use with their brakes and a 1" master cylinder. I went a step further and reduced the master cylinder piston to 7/8" for more pressure. Now I've got brakes that are as easy to work as any new car.

A typical manual pedal assembly would have a pedal ratio in the 6-7/1 range, to use with a 1" master cylinder. Of course, it requires more pedal travel, than a boosted setup.

Vacuum boosters may also be troublesome if you've got an engine with a big cam and low vacuum. A hydraulic booster may be the answer.

Really?

Okay that just made the decision for me. I have a few numbers to check now but I will go with a power set up from the start. Looks like I will have an extra MC....maybe I'll save it for my next project

Thank you much,

6696