Going from power to manual brakes- 1960 Bel Air 235 with 4barrel;disc/drum brakes and wanting to add manual disc brake master cylinder. Removed the power brake booster and matching mc w prop valve.The manual mc reservoirs are the same size so does it matter (front/rear) port I hook up the disc brake line? Can I use the power proportioning valve OR do I even need one? Or do I need residual valves ? Any help is appreciated
That looks like a Corvette (disc/disc) master cylinder. You can probably get away without a proportioning or residual valve, but since you already have it, you could install it, eh?
Typically, a disc/drum master cylinder supplies the disc brake from the larger front bowl, rear brake from the rear bowl. What you call a proportioning valve should be a 'combination' valve that allows brake pressure to the front bakes up to about 100psi then the flow quits while the flow to the rear gets continues up to above 300psi when that pressure overcomes the front brakes check valve and allows the front brakes to go to over 1000psi while limiting the rear brakes to about 400ish. It send fluid to the front brakes to take up the slack until the rear brakes are being applied and the front discs are applied at a much higher pressure.
I just need guidance. I don't know if it matters ; about the valves with manual brakes. As in picture you can see the new air filter cover over the 4barrel carb. Did away with the 2barrel setup.
You're kinda confused on combination valves, as they can simply be (2 way) distribution and pressure differential, along with 3/4 way added metering and/or proportioning. Metering does hold off the fronts fronts for about 100 psi, allowing the rear shoes to contact the drums. Full master psi is then allowed as it increases. Proportioning is a totally separate operation, restricting rear pressure up to a fixed or adjustable value, then allowing a percentage of increasing master cylinder pressure to the rears.
There is very little difference in the necessary hydraulic system, between manual or power brakes. The only difference is that you need a smaller bore master cylinder with manual brakes. The proportioning and residual valve requirements don't change.
IF the master function is 50/50, it does not matter which port goes to the fronts. Reservoir visual size does not always determine the correct plumbing, so if in doubt, make sure you know the intended design plumbing. Drum residuals, either internal in the master or external #10 valves, are a must on vintage brakes, and benefit later drums as well with a tighter pedal.
You're right about the residual and prop valve requirements staying the same. but needing a smaller bore master with manual brakes is not always true, as many vehicles used the same master size manual and power, and the popular early Mustang is one example.
But if these will clean up the look; I will buy them Sent from my iPhone using The H.A.M.B. mobile app
I'm kinda confused about lots of thing but not about how and what a combination valve is: A Combination Valve, commonly called a Proportioning Valve, is just what the name implies…a valve that does a combination of things. The valves are available for both disc/drum and for disc/disc brake systems. Valves for both configurations contain a Proportioning Valve and a Brake Pressure Differential Switch while the disc/drum valves also contain a Metering Valve. What is all of this stuff and what does it do? Read on and we’ll explain….. Proportioning Valve: This portion of the valve (seen below and labeled A) is used to control the rear brakes. There is a pre-set portion of the valve that regulates the rear brake pressure under heavy braking scenarios and prevents the rear brakes from locking up. Without this part of the valve, the rear brakes, which require much less brake fluid pressure than the front, tend to lock-up under a quick, hard press of the brake pedal. This is a potentially scary situation. Brake Pressure Differential Warning Switch: In the center of the Combination Valve (seen below and labeled B) is a single wire connector that works in conjunction with a slide in the center of the valve. If brake pressure is lost to either the front portion or the rear portion of the system, the switch grounds and illuminates a warning light in the instrument cluster. This is a warning that something is wrong. Metering Valve: At the front of the Combination Valve (seen below and labeled C) is the Metering Valve. The Metering Valve, sometimes referred to as a Hold-Off Valve, is used to regulate the pressure going to the front wheels when the brakes are initially pressed in a disc/drum combination. The disc brakes will apply much quicker than the rear drum brakes and if pressure is not slightly held off, a nose dive of the vehicle may occur under braking.
Ok I have three lines leaving the proportioning valve. I want to illuminate the proportioning valve due to limited space near that far wall. Why three lines leaving and not just two? Sent from my iPhone using The H.A.M.B. mobile app
wild guess...the three lines are: 2 fronts are going to each side, and one back line? The valve is a "combination valve", one of the many functions it serves, is as a TEE to the front brakes. You can replace that function with a simple brass TEE.
Ok thankyou.Since I am doing away with the proportioning valve will I need the residual valves? What tee do I need? All I know is that all 3 lines take a 3/8 flare wrench.
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