Residual pressure was required to keep the wheel cylinder seals against the bores. If there was no residual pressure, air could (and often would) be ingested with every lift of the foot off of the brake pedal. Thechange was the addition of a spring and steel cups to the wheel cylinder, which helped better keep the seals in place and working. The distribution block contains no metering provisions per se, but it does help keep the fluid flowing the right direction. The most important feature is the warning switch/pressure differential valve. For those of us that want a light to tell us when the pedal falls to the floor, this is vital. As far as adding a metering valve goes, it's not that necessary, although it might make for a more open prop valve. There are as many right answers as wrong ones, to this set of questions. My '67 'Cuda has all the orginal brake hydraulics on the chassis, but 11" rear drums, and the 10.87" rotors up front. I should have an adjustable prop valve, but have not yet installed it. Braking is excellent, with lockup of the rears only under the heaviest braking. The amount of rubber you have on the road at each end of the car, will have an effect upon how you need to adjust the valve. As for line-locks, they can be awesome, if you drag race or like to do burnouts. Properly installed in the front brake circuit, they are very useful staging devices, with an excellent service record (few problems).
Topic: Proportioning valve question- wilwood adjustable versus "combination valves" (Read 36624 times)
