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Hi All
For reasons I will not bore you with, I am having to change course on the master cylinder engagement on my 1949 Desoto.
The only major non-stock item on the car is the conversion of the front and rear to disk brakes. The rear uses the Cadillac Eldorado disk with the mechanical parking brake built into it.
I had designed a duel (two) master cylinder arrangement with a balance bar and it works. However, the vendor has told me that it is not designed to take a load from a brake pedal of more than 7 to 1 pedal ratio. The Desoto is in the (7 to 9) to 1 range. I do not want to risk breaking a M/C pushrod down the line.
So, we are looking at a couple of alternatives as I want the front and rear brakes on separate hydraulic circuits.
I know of all the kits out there. So far for various reasons we have decided that they will not fit the bill.
What I am looking into is something rather unique. It would however work on almost all MOPARS from the late 1930's until they went to the firewall mounted units in the 1950's. It would not matter if it was drum-drum, disk-drum, or disk-disk. Using the appropriate residual valves.
What we are thinking of doing is machining a cylinder that would screw into the back of the existing master cylinder. It would have a raised top, an inlet port and compensating port, and an exit port. The original master cylinder would have a outlet port drilled into the side and would have a machined cap to replace the filler cap.
In essence we would be turning the original master cylinder into a modern duel master cylinder. None of the mounting would change and the pedals would all stay the same. This unit would use firewall mounted remote fluid cylinders so there would be no under floor checking over time for fluid level.
I have sourced a 1970 +/- a few years Corvette disk-disk mater cylinder. We would use that master cylinder internal piston parts for this effort. That way we know the guts will be available for years to come.
I am planning on this for myself and may use it on the big '47 Desoto as well. I have a couple of friends with MOPAR's from the period who are interested as well.
Several of us have seen incidents in the last 5 years where new brake line hoses from NAPA and elsewhere have developed bubbles with one or two years use. Because of the uncertainty of the quality of bake hoses, wheel cylinder piston rubber or master cylinder piston rubber...I feel that a split system is more important today than "back in the day".
Anyone interested in or wishing to talk with me on this mini-project let me know.
James
