Power Brakes swap - distribution block?

[jcode68]

I am getting ready to do a power brake swap using an original Bendix style booster and master cylinder. Brakes are currently 4 wheel manual drums Am swapping the fronts to SSBC Force 10 discs, leaving the rears drum for now. My question is, do I need to swap out the distribution block located near the master cylinder for this swap, or can I use the one i have now?

 

[jcode68]

Bump. Anyone?

 

[SuperSnake428]

Don't use a distribution block, use a proportioning valve. Distribution blocks are specifically designed for certain cars with specific brakes/tire sizes in mind. A proportioning valve is what you want, look at the SSBC one on MustangDepot.

Drew

 

[jcode68]

Don't use a distribution block, use a proportioning valve. Distribution blocks are specifically designed for certain cars with specific brakes/tire sizes in mind. A proportioning valve is what you want, look at the SSBC one on MustangDepot.

Drew

Thanks for the reply. I have the proportioning valve from the SSBC kit already. So if I understand this right, the distribution block is only used for drum brakes at all 4 wheels? Proportioning valve is used for front disc setup. The distribution block has a brake switch in it which senses pressure I believe and then turns on a dummy light on the dash if there is a problem. So this essentially becomes unused with the new setup? Thanks for the help.

 

[180 Out]

I don't know about a '68, but the distribution block on a '65 with the standard single reservoir master cylinder has no internal valving. Therefore, when switching over to a dual reservoir system you can continue to use it to split the lines to the front brakes, after plugging off the port to the rear brakes. The question mark comes up regarding whether a distribution block also includes residual pressure valves. Drum brakes require 10 psi residual pressure in the lines when you release the pedal, to keep the shoes close to the drums. The residual pressure valve is usually built into the master cylinder, but sometimes it's built into the distribution block. Sometimes it's plumbed into the circuit down the line. That's why I say I don't know about the '68's.

 

[Rusty67]

180 is right about the distrobution block. If you are puting on a disc brake kit from the front you MUST change the master cylinder. If you use a master cylinder that doesn't have a residual presure valve built in for the rear drums, you will need to plum them into the rear circuit. If you don't, your brakes will never feel right. If you are gonna put power brakes on it I'm going to sugest using a booster from an 87-93 V8 Mustang. It is a little smaller then the older unit and is a direct bolt in. Also, it gives the pedal a much more modern car feel.

 

[Cannoball888]

I don't want to hijack this thread, but my question is similar. I have a '65 with manual front discs and rear drums, but I want to convert the rear to discs too. Do I need to change the master cylinder? What about distribution blocks and proportioning valves?

 

[Rusty67]

I was going to be posting my rear disc conversion but it has become severly delayed because I moved to a new house and there was nothing there but the house. We are still seting up all the irrigation and pouring all the cement. Once it is all done I will have time to do the conversion and a write up.

If you do put rear disc on, you need to change the master cylinder. The distrobution block can stay where it is. If you have a seperate proportioning valve, I sugest you get rid of it or have someone who knows what they are doing re-adjust it after you get your disc setup in.

 

[jcode68]

"180 Out - I don't know about a '68, but the distribution block on a '65 with the standard single reservoir master cylinder has no internal valving. Therefore, when switching over to a dual reservoir system you can continue to use it to split the lines to the front brakes, after plugging off the port to the rear brakes. The question mark comes up regarding whether a distribution block also includes residual pressure valves. Drum brakes require 10 psi residual pressure in the lines when you release the pedal, to keep the shoes close to the drums. The residual pressure valve is usually built into the master cylinder, but sometimes it's built into the distribution block. Sometimes it's plumbed into the circuit down the line. That's why I say I don't know about the '68's."

I will be replacing the master cylinder as well. I have 2 of them - 1 that came with the SSBC manual front disc kit and another that came with the Bendix booster I bought - I'm wonderring if this master was for disc/drum or all disc. Anyway to tell? Regarding the residual pressure valve, I will check my factory manual to see if the rear is plumbed with the residual valve already. I seem to recall that it is, but not sure. I haven't torn into anything yet as I was just getting all my parts together first.

Rusty67 - I already have the Bendix booster as I am told it is the only style which will not cause an interferance fit with the JMC hydraulic clutch. Thanks for the sugesstion though, good to know.
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[Rusty67]

If you look into the out ports on the MC you should be able to see in with a flashlight. Looking into them you should be able to see the residual pressure valve, or lack there of.

 

[thehueypilot]

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.

 

[Cannoball888]

^Did you change to an all disc master cylinder?

 

[Ronstang]

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.

 

[brianj5600]

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

 

[ultrastang]

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

 

[ultrastang]

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]

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.

 

[ultrastang]

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.

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

--Steve

www.ultrastang.com

 

[TIGGER]

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.