Brakes: Turner Brake installation on '57 GH with Hydrovac

[sldavidson75]

Installing Turner brake kit on 57 GH. Has hydrovac booster. How is the plumbing supposed to work? What I mean is with a dual master cylinder how do you utilize the booster with one in and one output? Does someone have a diagram of how this is supposed to work?

[JoeHall]

Key questions: What do you mean by, "Turner brake kit"? Also, did your car originally come with drum PBs? Put another way, are you including Turner front discs, or just the tandem MC? If including discs, and the car originally came with drum PBs, it is highly advisable to swap the PB pedal out with one for standard drum brakes, for more fulcrum on the pushrod going into the MC. Please answer the two key questions above, for more specific advice.

[sldavidson75]

turner brake deluxe kit. Came with MC and discs. Car originally had drum power brakes.

[StudeRich]

Is or Was the Drum Brake Type Hydrovac working properly?
It was not designed for the Higher Pressure Disc Brake System.

[sldavidson75]

Yes, I replaced the Hydrovac unit when I got the car.

[JoeHall]

If you replaced the original HV with another one just like it, it will still make stoping the now disc braked car stop easier than in no HV at all, but it will still leave you wishing for less pedal pressure to stop the car. The HV made for 63-64 GT Hawks with power disc brakes will result in much less required pedal pressure, since it puts out quite a bit more boost PSI. If it is a serviceable HV, I'd probably just live with it, but if a replacement is ever needed, I'd install a HV for 63-64 GTs.

One thing you can do to reduce required pedal pressure is to install a pedal that was used in standard brake cars of yours' vintage. Here is a pic, which says it all. Unless someone has already swapped yours out, it likely has the shorter pedal in the pic. Got good news is, the standard pedals are fairly east to come by, the bad news is, they are a real PITA to swap. Still, the swap is ver well worth it, unless you are still squatting 500 pounds or more in the gym. LOL

[sldavidson75]

Thank you!

[JoeHall]

Back to the 2nd part of your question. With your setup, the best way to plumb the brakes is to bypass the HV for the rears, and run the line straight from the MC to the rear. Run the front discs through the HV. Your car's 10" rears are self energizing, so do not need as much line pressure as the front discs. Turner's kit also comes with a proportioning valve for the rear line. It is, more accurately, a manually adjustable restriction valve, to restrict fluid flow to the rears, if needed. I have never needed to restrict the flow, but some people have. I suggest to install it, but leave it adjusted wide open. It will be there if you decide you need it later, and is easily adjustable.

[64V-K7]

If you replaced the original HV with another one just like it, it will still make stoping the now disc braked car stop easier than in no HV at all, but it will still leave you wishing for less pedal pressure to stop the car. The HV made for 63-64 GT Hawks with power disc brakes will result in much less required pedal pressure, since it puts out quite a bit more boost PSI. If it is a serviceable HV, I'd probably just live with it, but if a replacement is ever needed, I'd install a HV for 63-64 GTs.

One thing you can do to reduce required pedal pressure is to install a pedal that was used in standard brake cars of yours' vintage. Here is a pic, which says it all. Unless someone has already swapped yours out, it likely has the shorter pedal in the pic. Got good news is, the standard pedals are fairly east to come by, the bad news is, they are a real PITA to swap. Still, the swap is ver well worth it, unless you are still squatting 500 pounds or more in the gym. LOL

The standard pedal pivot is welded to the frame closer to the MC than the power brake pedal. The PB pedal has a mount which is bolted to the frame around 4-5 inches farther toward the engine. The MC stays in the same spot, so changing pedals will require a shorter actuator rod from the pedal to the MC. The return spring may need some help also.

[showbizkid]

sldavidson75 , I've taken the liberty of editing your post to have a descriptive title. In future posts, please make sure you state the year of the car you're working with and explain a little more about your question. One-word post titles are no good for future users who might be searching for the same info.

Also, please be sure to select the category of Tech question from the Prefix drop-down when you post in the Tech Talk channel. It helps categorize the questions for future searches.

Thanks!