I have a question and the folks here on this site are so knowledgeable that this is the place I turn to for answers. So, thanks a lot for all of the help so far. My new issue is a 1956 Mercury that I am working on. It had factory power brakes but is the old style with booster/single master cylinder all together. I am running drum/drum and would like to update to a more modern system with dual MC. Originality is not a problem. I see sites that sell dual MC/boosters but state that will not work with a factory PB system. I am guessing this is because these ones they sell have a "bell crank" type system to correct the ratio of the pedal/booster. My pedal setup has that type of thing inside on the pedal/bracket parts. It changes the ratio by using that. I also see the street rod less expensive booster/MCs that do not have that bell crank and appear to have just a 3/8" threaded rod out the back of the booster, which luckily mine does too so my rod should attach there. Has anybody done this and have any input? It is a 7" single booster, 1" bore Corvette style MC. They said if I use it, I would need 10# residual valves in both lines (front/rear). I am thinking that this simpler style would work with my pedal system without a whole lot of mods, maybe just the mounting holes being off just a tad. Any help greatly appreciated.
if I understand you correctly you are looking for help in converting your stock (treadle vac)system.if so google is your friend there are post out there already.
Quick google search shows plenty of Chevy conversions, but I am more curious about the crazy pedal setup in the Merc., not sure if Ford used the same or not. I haven't found any info for Mercs or Fords yet
not sure what you mean by crazy pedal setup.you can adapt the info to your car if you are handy.if you are not confident doing the conversion than learn to rebuild the treadle vac.the treadle vac worked for many years on a variety of makes.
There is a scissor type action setup attached to the pedal that changes the travel of the rod that goes to the booster. The rod is not attached to the pedal, but to that scissor pivot part. Never seen anything like it. I know a standard brake pedal does not have the correct ratio (pedal pivot to rod pin location) that a PB pedal does. I think I am going to buy a standard booster/MC combo and hook it up to the factory rod. I will find out if it works. Thanks for the help.
Hey so how did the brake situation work out. I got a 56 Merc in May. Original manual brake car, but previous owner added a booster & MC on it using the original pedal assembly. Something doesn't feel right. Found a oem power brake assembly, thinking of swapping it out to see if it improves.
there is a formula for figuring the different pedal ratios between power an non power.that could be what you refer to.wish I could remember it.google may help
I bought a power brake M/C kit from Ebay a few years ago. It bolted right on to the firewall with no mods. Chevy style dual res M/C. Works great with my original merc drum brakes on all four corners.
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