Thinking and Planning

One thing I find prevalent in the poking around I've been doing is this: The pedal ratio may be too low. According to popular sources on the Web, the pedal ratio must be in between 4:1 to 5:1. Apparently some older cars, like the ones from the late 50’s, that had power brakes from the factory used a ratio of almost 1:1. Obviously that would produce a very hard pedal. But how much can I change the ratio with the existing linkage? And, what if the volume the master puts out is still low even after doing all of that. I am thinking the best way to go would be to dispense with the current rig and switch to a swing pedal.

With a swing pedal something like this, I thought I could use the master ($30) that GM used with those calipers I bought. Then I'm sure the volume is there. (I asked Scarebird and they said not to worry about using a Fast Fill/Quick Take Up master. They say it makes very little difference in the amount of pedal travel.) The Esky master is too big to fit the hole in the booster, so I need a matching '00 booster... yes I ordered one ($140) from Amazon. I won't know if I have enough room for the Esky booster until it arrives as I have no idea what diameter it is. I should be OK with up to 10". I have the swing pedal from the Coupe Devil... a '73 Cad, that might work. I thought that since the car already has a sort of swing pedal arrangement that it might be modifiable to work. But the Esky master needs 2" of travel to bottom it and mounting a pin at the spot on the existing pedal that would give me that amount of travel works out to less than a 2:1 ratio. Too stiff! Looks like I need to mount the '73 Caddy pedal which has a ratio of a bit more than 4:1.

Ugh...

BTW: I found a book online that informed me that I can tell a Fast Fill/Quick Take Up master by looking for a bulge in the casting. Sure enough, the Esky master has the bulge.

So it stands to reason a conventional master won't work well with the calipers I got for the Scarebird disc setup, even though Scarebird says it won't matter significantly. Apparently the bulge is the reason the master doesn't fit the booster for a conventional master. (Duh!) So if I can't get the Esky master/booster combo to fit or work, I'm gonna have to go to a conventional master/booster or call Master Power Brakes and find out what they have that I can use.

Another issue with an FF/QTU master is, it can apparently take a lot of time to bleed the rear brakes, due to the small refill port from reservoir to rear bore. The suggestion is to take at least thirty seconds before reapplying the brakes after each stroke, to allow time for the rear bore to refill. Not a big deal, but something to be aware of.


Double Ugh...