smash72

Installing new master/booster combo comes with side mount Proportioning valve. I have a 72 Cutlass front discs rear drums simple question do I even need this valve. Seems like it's only purpose would be in a emergency stopping situation this valve would limit the pressure to the rear drums and let the front discs do all the heavy lifting for stopping the car. If that is indeed the meat and potatoes of its main purpose I don't need it. I will take my chances with the less than 1000 miles that I drive it a year. Plus as is lines line up perfect for a quick install. This valve doesn't seem worth the effort of replacing lines to neatly reach the new valve ports. Also seems like one more thing that could add air into the system. (That last comment was a bit of a reach, I really just wanna drive my car and I need someone's permission to **** can this valve or at least toss it in a drawer.

smash72

Quick pic of my new Right Stuff oriental pos combo master/booster it's a temp.

joe_padavano

The whole point of the prop valve is to prevent premature lockup of the rear wheels, which can cause the back of the car to come around if the front wheels are turned at all. Keep in mind that the stock brakes need to operate under the full range of weather, road surfaces, and loads in the car.

If you have the front and rear brakes matched EXACTLY for the weight distribution and tires on a particular car, you don't need a prop valve. I seriously doubt this is the case. Is there some reason why you don't want to install it?

smash72

In the short term I wanted the car back on the road for a local car show. I would need to replace the lines there to short as is and too brittle to try and bend. I have every intention of replacing them soon I just don't have any time right now. Another question is the bleeding of the master before you start the bench bleed if you will. Had enough trouble fabricating the brackets and getting it mounted would have been a mess trying to mount full of fluid. I read it's ok to bleed the master already mounted. My concern is the extreme angle these things sit at if bleeding the master will be a problem. Don't think I can back off the top mounting bolts just to level for a bleed, again bracket issues. Ended up cutting the riveted brackets off the 11" booster then some reaming here hammer there got them to work. This is obviously my first crack at the bleed process other than my bike.