Hello All, I had read in someones gallery that they changed the brake pedal ratio to bring the pedal down to the same level as the gas pedal. How is this possible. It was in a 65 F100 if I remember right. Does this still give proper brake pressure? I have converted to front disks on my 66 F100, does that matter? Thanks for the help, Kris

 

its possable top make it work, you need to move the hinge point higher up under the dash, so the ratio between the pedal and the break plunger pin is closer. You'll need some heavy welding skills and the ability to fabricate the brackets in thick enough steel.

the only problem with this is, after making it all work out, if your engine stalls, or you lose the boost on the brakes, you may not be able to push hard enough to get stopped. I wouldn't do it that way unless it was going to be a show truck, but it does look good when its done.

there are other things you can do, though. One is find out how close to the firewall the pedal goes before it's pushed the plunger all the way while the break resivore is empty. then trim the plunger pin down untill the pedal is almost against the firewall at that point. That may gain you an inch or two. Then, figure out how much of the initial travel of the pedal is just slack, and build a new bumpstop so it eliminates most of that slack. you should be able to pick up another inch or two there. Finaly, move your gass pedal out closer to the brake pedal. A bracket for the gass pedal is much easier to build. you can probably move it out an inch or two without the need for welding.

 

Go to www.mpbrakes.com and order their catalog. The first half of the catalog is a technical manual that covers this brake pedal ratio business. If you have the wrong ratio you will have touchy power brakes or a very hard pedal on non-boosted systems. The information is worth the cost of this catalog.

 

I think you may be talking about my gallery. 66beater is right about needing to weld and fabricate. Here is what you have to do:

Measure from the brake pedal pivot point to the booster rod mounting point. Call this "Y". Measure from the brake pedal pivot point to the pedal. Call this "X". Now divide X by Y. The result is your pedal ratio. According to Master Power brakes the pedal ratio for manual brakes is 6:1 and for power brakes it is 4:1. The reson for this is that with power brakes you don't need as much leverage. The extra leverage actually makes the brakes overly sensitive and can be unsafe.

In order to acheive 4:1 on your f100 you will have to move the booster rod attachment point on the pedal closer to the brake pedal's pivot point. You want the rod to remain level so you have to move the whole booster/ master cylinder assembly up an inch or so (I can't remember the exact measurement). So you make some brakets to move it up and use the same mounting studs in the firewall. These mounting holes are reinforced because your pushing on them with a big lever (the brake pedal) all the time. Do not try to drill new holes and mount new studs in the firewall. I made the brakets from some 1/8" thick angle iron and a MIG welder in an hour or so.

Then open up the hole in the firewall which the booster rod passes through and make a new (bigger) seal. Drill a new hole in your brake pedal and bolt up the rod. Now your done and you have a brake pedal with much shorter travel, and you power brakes won't be so touchy. Since the travel is so much shorter you can adjust the rod to bring the pedal down so you don't have to move your whole leg to brake the truck.

I don't know about what happens if your truck stalls as 66beater points out. All vehicles with power brakes have about a 4:1 pedal ratio so I guess it's safe. Heck, I didn't believe it myself until I went out and measured my 2000 4runners pedal ratio and found it is 4:1! I have been driving my truck with this modification for over a year now and am very pleased.

I hope you find this helpfull.

Greg

 

Thanks fellas, the info is great. Greg, it was your truck I was refering to, very nice by the way. Kris

 

Ford mechanical booster brackets are available by the hundreds in junk yards. These brackets raise the booster to clear the rockers on FE and 460 engines. The brackets are a 100% bolt in deal using Ford parts. New firewall boots are available from Mustang suppliers. If you keep the small pedal pad and old brake pedal arm you need to drill a hole about an inch down the arm and the same size as the one already there. Or, you can mix and match the old support and one of the wide pedal pad arms to achieve the same thing without any drilling. By building basically the same truck from 65-79 Ford really helped those of us that like to improve our trucks with junk yard parts. Like this brake pedal deal or power steering, disk brakes, or installing any one of the engines built from the same era using all Ford junk yard parts.