Install a proportioning valve to a master cylinder during high-performance brake installation on a classic muscle car; learn how from our expert mechanic in this free auto-restoration video.
Mark is installing a bracket now for the proportioning valve or a combination valve. This piece here is the proportioning valve. Mark is trying to line up the hardware they're providing with the kit. There's a bracket down below and there's some brake lines on the combination valve. It's all supposed to cosmically line up so you can mount the proportioning valve right on the master cylinder assembly. When you go to install it, you don't have to run separate set of lines down. Originally, the combination valve on most of these American cars is mounted down on the frame. In this one, they're trying to make it easier. So he's just mocking up right now to see where the heck the thing is going to line up with which lines and which holes. Mark's got the combination valve mounted to the master cylinder now. It's--the combination valve, make sure you get the right proportion of brake pressure to front and rear brakes. If you have a brake light on your car, it will go on if there's too much pressure going to one or the other indicating a brake problem. You'll see there's a couple of different colors of fittings. It's kind of a mix and match. As a general rule, colored fittings or metric natural colored fittings are domestic sizes. So we have this late model Corvette master cylinder and booster going in the car--into a car with domestic fittings so there's going to be a kind of a mix and match there. The reason a Corvette master cylinder is chosen is because the Corvette has a real good volume of the master cylinder and the size of the booster, the big gold sucker there behind the master cylinder, the diameter of that is small and fits in with a lot of these adaptations that we do.