Proportioning Valve for Power Brake 66 Coronet??

[SassyPants]

Hello Team, several years ago my brother and I restored a 68 Mustang, Cal Special. We put Power Brakes with dual Res on that car and it required a Proportioning valve to reduce pressure to the Back Brakes slightly as compared to the Fronts.

As I am changing my 66 Coronet Power Brake Car from a Single Res Master Cylinder to a Double Res, I expected to see a Prop Valve come into play? MOPAR did not use Prop valves for Brakes? So, does that mean Backs get same pressure as do Fronts? Or is there something in the system that that reduces pressure slightly to the backs compared to the fronts? Best, B.

 

[JimCoronette]

Are you adding disks up front or keeping the drums?

 

[SassyPants]

Keeping Drums. B.

 

[R/T Boy 67]

The factory used different size wheel cylinders front to back, to reduce the force on the rear drums, but the pressure was the same.Rear shoes were often smaller as well. If you didn't need a prop. valve before the master swap, you won't need one now, as long as the wheel cyls and shoes are the same.

 

[SassyPants]

Perfect. The wheel cylinders are stock, right out of the box. did not have a prop valve before. So, we are good to go. Thanks a ton guys, B.