Power Brakes swap - distribution block?

My 68 had four wheel drum brakes and I reused the same distribution block but added an adjustable proportioning valve into the rear brake line and the four wheel disc brakes work good.

^Did you change to an all disc master cylinder?

I get a TEE from a trailer place to spit the line going to the front brakes and then use an adjustable proportioning valve in the rear line. Just make sure you get a master cylinder for a front disc and you will not have to worry about the residual valve issue. One from a late 70s Granada is a good choice.

Is there a place on the web that has master cylinder bore sizes that bolt up to a Mustang?

If you have an all-drum setup, you need a master cylinder configured for a 4-wheel drums.

If you have discs front/drums rear, then you need a MC that's setup for this configuration.

If you have 4-wheel discs, then you need a MC for 4-wheel discs.

I've never done this, but you can remove the residual pressure valve from the port of a drum brake MC when changing over to discs. --I've just always installed MCs that were setup for the type of brakes I was installing, though.

If you have a power brake booster, MCs with bore sizes over 1" isn't a problem. If you have manual brakes though, it's best to keep the MC bore size between 15/16" to 1" in diameter. Greater than this with manual brakes is going to be tiresome on your leg if you have to make repeated brake applications.

The '67-up 4-wheel drum brake Mustangs have distribution valves. These have a metering circuit to sense if there is a pressure loss (brake failure). If, for instance, the rear brake line ruptured the valve spool inside the valve body would shift to the side of least resistance (the failed side), and stop fluid flow to the rear brakes, but still leaving the front brakes operational.

Factory distribution & proportioning valves are all designed for specific brake system types. As an example; if you had a vehicle with 4-wheel drums and then converted to Granada front discs, you would need to install the factory Granada (disc front/drums rear) proportioning valve. However, if at a later date you converted the rear to discs as well, you would need to change the valve again for one that's configured for 4-wheel discs.

The old Granada disc/drums valve will work with the newly installed rear discs, but it will not work properly because the Granada valve is designed to meter brake fluid at a specific rate to the wheel cylinders of a drum setup, not to the pistons of a disc setup.

Here are some brake setups I've done;

1. http://www.ultrastang.com/Ultrainfo.asp?Page_ID=15

2. http://www.ultrastang.com/Ultrainfo.asp?Page_ID=16

3. http://www.ultrastang.com/Ultrainfo.asp?Page_ID=16

4. http://www.ultrastang.com/Ultrainfo.asp?Page_ID=17

5. http://www.ultrastang.com/Ultrainfo.asp?Page_ID=18

Whoops! Had two duplicate links in previous post. One of the links should have been this one;

http://www.ultrastang.com/Ultrainfo.asp?Page_ID=11

jcode68 said:

Ultrastang - Thanks for the info and the links! Will spend some time on your site doing some reading. Appreciate you taking the time to document all the updates on your car, these will be very helpful.

Click to expand...

No problem. I hope you find some useful information from my website.

--Steve

www.ultrastang.com

Sorry to Hijack but I have some questions now. Is the distribution block the proportioning valve on a 67/68 car? I am getting ready to do a front disc brake swap on my 6 cyl coupe. I will use the Scarebird brackets and other wierd parts to keep my 4-lug wheels. I plan on using a 67 Mustang disc brake MC but I am not sure if I need to do anything with the distribution block or add an adjustable proportioning valve. If I need an adjustable valve, can I keep my existing dist block and how does it plumb in? I see that the parts vendors sell a repro 67 disc brake dist block, can I install one of those and be done? I want to keep it looking as stock as possible with little or no brake line fabrication.