[justjohnny]

I have a 66 GT with factory front disc brakes and a Kelsey Hays proportioning valve. Presently manual brakes. I'm looking to switch to a dual bowl master cylinder and power brakes. Called CJ Pony parts and spoke to a tech. He said that the original proportioning valve will not work with the power setup. I'd like to keep it instead of using a new type. What's your opinions.

 

[patrickstapler]

Don’t waste your time. Do this instead. I just did it on my ‘66 GT and it fits perfect.

LEED Brakes Hydraulic Master Cylinder Upgrade Kits FC0006HK

Find LEED Brakes Hydraulic Master Cylinder Upgrade Kits FC0006HK and get Free Shipping on Orders Over $99 at Summit Racing! Upgrade your car to a 1 in. dual-bore master cylinder with LEED Brakes hydraulic master cylinder upgrade kits. These kits will allow you to upgrade your factory...

www.summitracing.com

 

[Westmus]

I believe the tech is wrong. The only difference between the manual and a power system, is that you with the power system got a "friend" helping you pushing the pedal. The original disc MC on your car even got two lines out, just like the new dual MC you want.

 

[patrickstapler]

And this...

Mustang Disc Brake Proportioning Valve

1965-1966 Disc Brake Proportioning Valve Rebuild

www.stangerssite.com

 

[CHOCK]

Why power brakes--Do you have a disability? Unable the press on the pedal?
If so you will need the aid of a booster to help in the effort. If no disability, no impairment, a booster/power brakes are not needed.
To deface a original GT car, add a non stock, will fit booster -Guarantee China brand, is not the way to go.
A dual bowl master will indeed work with your original P valve.

 

[patrickstapler]

BTW, I wouldn’t even switch to a dual bowl MC if I weren’t open tracking my car. I actually drove it for four years with the OEM GT MC. Not one single problem. Installed quality Porterfield R4S pads and could stop effortlessly.

 

[Nailbender]

I see no reason why you would need to change the proportioning valve to upgrade to a dual bowl MC or power brakes as it is down stream?

What I don't get is the hate for anything power assist on this forum even from those that make a living rebuilding it? I framed houses for 35 years and in all that time I always enjoyed the benefits of power steering and brakes. Now that I'm a hunched over pile of poo from framing houses for 35 years I REALLY enjoy the benefits of power steering, brakes, and hydraulic clutch. When on the autocross course I want the easiest steering brakes and clutch that is possible as that is the only way to be somewhat competitive. I guess I don't get the whole pissing contest thing?

 

[myfirstcar66]

@Nailbender , @justjohnny, build and enjoy your car the way you want. I'm thinking about adding power steering to mine, 22 years into a law enforcement career I did like an NFL tackle, facet joint spine injuries AND a surgery to reconstruct the AC joint etc in a shoulder dislocated 3x, and seeing how easy my son's car is to drive with power steering. Besides, if you don't like it, you can always unbolt it. Rock on.

 

[GT289]

What I don't get is the hate for anything power assist on this forum even from those that make a living rebuilding it? I framed houses for 35 years and in all that time I always enjoyed the benefits of power steering and brakes. Now that I'm a hunched over pile of poo from framing houses for 35 years I REALLY enjoy the benefits of power steering, brakes, and hydraulic clutch. When on the autocross course I want the easiest steering brakes and clutch that is possible as that is the only way to be somewhat competitive. I guess I don't get the whole pissing contest thing?

Build it how you want it........ That said, I refuse to endorse power brakes in a situation where it is generally unnecessary
and it (generally) also introduces vagueness into stopping the vehicle.
If I want to feel disconnected from the driving experience I'll drive something modern, not a vintage Mustang.

ex-Global West GM
1991-1995

 

[patrickstapler]

I don't think of it as a pissing contest, but rather a difference in opinions and how each driver wants the driving experience to be.

 

[justjohnny]

Thanks for all the feedback. I do keep the car as original as possible and anything that I replace the old part goes in a ziplock bag to be saved. The car has power steering but the stopping power of the manual brakes is abysmal. Car only has 39,000 miles. However I am turning 64 with lymphoma and 2 bad shoulders (one of them having been reconstructed). Both my other cars are a 2014 and a 2016. I'm looking for the pleasure of knowing that My Stang can stop nearly as well as they do.

 

[patrickstapler]

So what makes you think a vacuum brake booster is going to make it stop better? Install Porterfield R4S pads on the front and braided stainless hoses front and rear. Make sure the system is adjusted and bled properly. Then report back to us.

 

[GT289]

Or feel free to spend a bunch of money on a power brake booster setup and then report back to us
(that it still stops abysmally).
You'll discover that it was the crappy friction material all along. That's my crystal ball prediction.......

ex-Global West GM
1991-1995

 

[Woodchuck]

The car has power steering but the stopping power of the manual brakes is abysmal. Car only has 39,000 miles.

If the above is true then you have an issue with your existing brake system. While front disc brakes eliminate some of the issues inherent with drum brakes, such as water flooding and heat dissipation, with the proper friction materials and adjustments their stopping power will equal their front disc counterparts. Also, with their "self-energizing" action, they typically require less pedal effort than front discs.

If you aren't commuting over a mountain or driving through standing water on a regular basis you may want to consider having your existing system repaired and, if need be, simply install a power booster like they did, originally, from the factory.