Pi*the square of the radius*PSI gives you the boost. 15 inches would be 7.4 PSI. A seven inch booster would be 3.1415*3.52*7.4 or 285 pounds of force coming off the booster to the MC piston.

An 8 inch booster would be 3.1415*42*7.4 or 372 pounds of force.

A dual 7 inch would be 570 pounds of force (2*285).

 

Perfect timing to see this post. I am about to order all new brake parts for my 67 F100 4x4. Everything will be new from the MC / booster all the way down to the drums. I like the idea of the plastic / aluminum MC as rust on my old iron one was a huge issue. Pulled my old MC the other day to see how the internals have held up and even the bottom of the MC bowl was a thin layer of rust. I feel like the Explorer MC would be a nice upgrade. Already have all the new brake shoes, going to be ordering all the parts you listed, all new wheel cylinders, hardware, and drums as well. I plan on replacing all of the brake lines. I'll take some photos of everything once it's done.

 

I don't know what booster you intend to run and MC bore sizing can have a big influence on how your brakes operate and how much or how little force you have to apply to the brakes to get the vehicle to come to a stop.

I have a dual diaphragm Bendix booster from a 1975 F350 (the booster came from O'Reilly's --54-73112. I traded in the donor core booster). It is an 8.795" diameter booster (times two diaphragms at this diameter).

I initially went through my 4-wheel drum brakes, beginning a couple of days after I bought my truck in April, 2011. By 2012, I added the F350 booster and just mounted the 1.00" bore MC to it that I had bought a few months earlier. I figured my brakes would be sensitive with the 1.00" bore and they were.

After I swapped to front discs in 2014, I changed out the cast iron 1.00" bore MC for a 1-1/16" bore '95 Explorer MC. My F350 booster isn't mounted to a bellcrank assembly on the firewall. The booster input rod connects from the back of the booster and directly to my stock '69 F100 brake pedal. This means my pedal ratio did not change (reduce) in going from manual brakes to power brakes. A high pedal ratio with a powerful 8.795" dual diaphragm booster and a small 1.00" bore MC equals lots of output pressure --and definitely way too much for all-wheel drums.

If the pedal ratio isn't (or, can't) be reduced when swapping from manual to power brakes, the only way around this is to go up in MC bore size to reduce the sensitivity on the brakes when the pedal is applied. By me increasing the bore diameter by 1/16th of an inch, it reduced the output pressure by around 6% and got rid of the sensitivity issue.

The factory '75 F350 Bendix dual diaphragm booster, '77 F100 front discs and the '95 Explorer 1-1/16" bore MC work really well together on my truck.

MCs with a bore diameter greater than 1.00" generally do not work very well on a single diaphragm booster. It generally results in brakes that aren't very responsive and will generally require a good amount of leg force on the brake pedal to get the vehicle to come to a stop.

 

I have had 3 different remand boosters and only 1 worked anywhere close to these new boosters Im using. And they were all be bendix. Remand parts are hit or miss.

Ultraranger you're the man, who gives a crap ton of detailed info. sometimes too much lol better to have too much then too little am I right?

 

You've helped out alotta' guys bud. Myself included, with the details.

 

So I'm a little fuzzy on which booster I should use and how they mount to the firewall and pedal assembly.

Will a booster hook to the original pedal assembly? Or do I need a dentside pedal?

I want to use the explorer master with the larger bore, so as to reduce pedal travel required. Is that going to be the 90-94? Or the 95-97?

And the proportioning valve? What do I need to use there?

I also plan on using drilled/slotted rotors and performance friction brake pads. So I'm kinda excited.

 

I quote Steve. I believe he used a bullnose Prop valve because he bought a new one. If your donor's prop valve is good I believe it will work.



"After I swapped to front discs in 2014, I changed out the cast iron 1.00" bore MC for a 1-1/16" bore '95 Explorer MC. My F350 booster isn't mounted to a bellcrank assembly on the firewall. The booster input rod connects from the back of the booster and directly to my stock '69 F100 brake pedal. This means my pedal ratio did not change (reduce) in going from manual brakes to power brakes. A high pedal ratio with a powerful 8.795" dual diaphragm booster and a small 1.00" bore MC equals lots of output pressure --and definitely way too much for all-wheel drums.

If the pedal ratio isn't (or, can't) be reduced when swapping from manual to power brakes, the only way around this is to go up in MC bore size to reduce the sensitivity on the brakes when the pedal is applied. By me increasing the bore diameter by 1/16th of an inch, it reduced the output pressure by around 6% and got rid of the sensitivity issue.

The factory '75 F350 Bendix dual diaphragm booster, '77 F100 front discs and the '95 Explorer 1-1/16" bore MC work really well together on my truck."

 

Ok, that explains it a little better. I guess it's gonna depend on which booster I get. I don't mind having to push on the pedal. So I'm thinkin a regular 8" dual booster with the 1-1/16 master cylinder should be fine for me.

Guess I'm gonna have to go visit my old buddies at oreillys and dig through the system and see what's available.

 

Slotted and drilled rotors look cool but the reality is slotted would be better than drilled. Drilling the rotors takes away significant material from the friction surfaces of the rotors. This reduces the rotor's mass. Less mass equals less material to transform the kenetic energy into frictional (heat) energy and then to release that heat to the surrounding ambient air flowing across the rotor's surface.

A solid rotor can absorb more heat than a drilled rotor. This means a solid or, slotted rotor will resist fading for longer than a drilled rotor that does not have as much material mass.

Drilled rotors also tend to stress crack between the holes when the brakes are subjected to a lot of heat. They're fine on a race/track car, since things like this would be changed out frequently on a race car. Other than for looks on a street vehicle though, they're really not practical and will reduce your braking ability.

Aggressive race-grade pads will work fine on a race car but will suck on a street vehicle. They have to have a fair amount of heat built up in them before they will be effective at stopping the vehicle. This isn't very practical on a street vehicle --particularly if you've been driving along on the highway for an hour or two since the last time you stepped on the brakes and now, all of the sudden, you have to jump on brakes that are cold and non-responsive.

I wouldn't even recommend buying something like the Wagner Premium brand pads. They are a very hard compound friction material and don't stop well. Get a cheap assed set of pads and they will be effective at stopping your truck. That may sound counter-intuitive but, it's true.

 

Hmmm. You make a good point ranger. I forgot about the stress cracking thing. I've heard that before too. It would be nice to have the extra cooling ability, but I guess my deciding factor will be the price difference. (Which means I'll Probably go with standard units)

The pads aren't really a race pad, just high quality carbon metallic. We've used them on our ranger and super duty for years. Always quiet and always bite hard. Performance friction is the brand of em.

 

There were essentially four basic designs of the F350 dual diaphragm booster. The type I'm running on my '69 F100 is in the second example given in the following link.

https://www.ford-trucks.com/forums/1...l#post16380503

 

check out EBC brakes , they have a matched performance rotor/pad kit for the Dents .
I was wanting it but didn't have the money .

 

Eee-gad! Over $330 for them. I sure can't afford that.

 

Regular OEM type rotors and pads will be more than adequate. Put your money on other improvements.

 

I think I will. Rotors anyway. I'd still like to swing for the carbon metallic pads. But pricing will decide.