Re: 1953 Patrician: has anyone updated from Treadlevac to modern 2-chamber mstr cyl?
Posted by Mopar_Earl On 2023/11/29 14:34:20
Quote:
Pretty sweet. A hydroboost may fit in the spot if you'd want power brakes and the pedal ratio was correct. The OE ps pump isn't enough though. You'd have to upgrade the pump or run a second pump. If they did the pedal correctly, it would be in the 6 to 7 ratio for manual brakes. Too much for power brakes.
Your braking performance:
If you have drum/drum brakes yet. Manual drum/drum brakes need a master cylinder with a bore under an 1" or you will make the pedal harder as you go up in bore size. And/or the ratio is too low. 4 for power 6 for manual. Could be as easy as installing a smaller bore master cylinder.
Another needed item on a drum/drum is 10 psi residual valves. If the master is originally a drum/drum master, it should have them built in. If not. You can add them externally. No residual valves would cause more pedal travel but you can pump it up and it holds. A disc/drum master would only have the 10 psi residual valve on the rear circuit. Disc/disc would have none.
Thanks
Earl
kevinpackard wrote:
This may not help you since you are looking at a boosted master cylinder. But my car was modified by the previous owner to have a dual master cylinder, though mine is not power assisted.
The PO removed the TreadleVac. He located the master cylinder high on the firewall, above the steering column and beside the fresh air duct.
I'm not sure what this master came out of, but I believe it is an old Ford model. There is a proportioning valve underneath it.
For the pedal he used something massive....it looks like it came out of a van or something. The linkage is above the steering column. He had a mechanical switch, which I disconnected and went back to the original pressure switch set up.
The pedal arm is very thick and wraps over the steering column to place the pedal properly.
The pedal appears closer in this photo than it really is. It's not hard to reach , though it sticks forward a little too far.
I don't love the set up, but I don't hate it. It works and I do like having a dual master. However I don't feel like it stops as well as a factory Packard manual setup. It takes more force to do a panic stop. I have no idea what the pedal ratio is. It works well enough, which is why I haven't bothered to change it.
-Kevin
Pretty sweet. A hydroboost may fit in the spot if you'd want power brakes and the pedal ratio was correct. The OE ps pump isn't enough though. You'd have to upgrade the pump or run a second pump. If they did the pedal correctly, it would be in the 6 to 7 ratio for manual brakes. Too much for power brakes.
Your braking performance:
If you have drum/drum brakes yet. Manual drum/drum brakes need a master cylinder with a bore under an 1" or you will make the pedal harder as you go up in bore size. And/or the ratio is too low. 4 for power 6 for manual. Could be as easy as installing a smaller bore master cylinder.
Another needed item on a drum/drum is 10 psi residual valves. If the master is originally a drum/drum master, it should have them built in. If not. You can add them externally. No residual valves would cause more pedal travel but you can pump it up and it holds. A disc/drum master would only have the 10 psi residual valve on the rear circuit. Disc/disc would have none.
Thanks
Earl
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