Don't forget the residual valve that prevents the springs in the rear drums from pushing all the fluid back towards the master and you then have a brake pedal that goes to the floor first thing in the morning.

 

You can put the prop valve a little farther back than right at the master cylinder. Many racers will put the prop valve(s) in the cockpit so they can adjust them as they race. The most complicated I saw had a prop valve on each wheel. Talk about control...

Unless you're using an aftermarket master cylinder, the residual valves are built in. Disc brakes need 'em too, just less pressure (2psi vs. 10psi for drums).

 

WHOA, residual valves? The ten and two pound type? I've read about these valves and how they work, but do you really need them? If so where the heck do they go?

 

If a braking system uses drum brakes the master cylinder should be equipped with a residual valve. This check valve maintains approximately 10# to 15# of hydraulic pressure [priming pressure] on the hydraulic circuit, from the master cylinder out to the drum brake wheel cylinders . This reduces the time of brake activation, by overcoming the pressure created by the drum brake return spring.
If , howeveryourMustang is to be equipped with DISC Brakes the 10# to 15# pressure created by the residual valve will partially activate the disc brakes during highway travel , causing brake overheating and failure.
If the master cylinder is equipped with a residual valve it will be necessary to remove the residual valve to eliminate it's hydraulic effect on the disc brakes. If you have bought a dual reservoir MC designed to be used with disc brakes, it will not have a check valve in it though, so no sweat.

 

Go to stang-aholics.com...........they have a biullet aluminum dual m/c with proportioning valve under the m/c. Get the distribution valve from the junk yard. Also, it is POWER and fits behind tghe spring tower. $450.00!!

 

Then why did they come with them from the factory? I think they called them 'delay valves'. I converted my 65 to factory discs and had to install the residual valve to prevent a 'pedal-to-the-floor' if the car sat very long....like 3 days. The valve is installed on the rear line and holds the pressure ONLY on the output side...which if you installed it correctly would do nothing to the front because the 10# of pressure is exerted on the rear wheel cylinders to counter the approzimatly 10#psi the springs on the drum brakes exerts on the line.

 

One word, "Pascal's law", if you understand this, then all this brake stuff is simple. I use the adjustable type and mountit within my reach from the drivers seat. I set the front brakes to lock up just before the rear. When you mix and match front and rear pistons thru aftermarket or harvested disc sets, then you will probly alter the surface area of the piston(s) that the factory valves were designed for. This may cause erratic braking at least,and could make the rear lock up first. Then "De ars wil pas de nose. Dat notta ood". The two pound residual needs to be used if the master cylinder is lower than the brake piston. Notta gona happen in our Stangs unless you are sliding down the road on your top. In that case it wouldn't matter much anyway. Braking systems are simple hydraulics, one piston surface area (master cylinder)forcing a non compressable fluid (brake fluid) thru a non expandable hose or tube (brake line/hose) to another piston surface area (caliprer) to deliever force (brake pads or shoes). Dats my $.02.