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Infinite Monkeys
08-28-2017, 01:04 AM
Here's my brake booster and dual piston MC install.
I used this from Summit:

https://www.summitracing.com/parts/tff-2123nb-1

I ran all new Nickel/copper alloy hard line, front and back. Highly recommended, it bends and flairs very easily and will never rust.
I reused the old distribution block for the front and bought another one for the back. I put in a new pressure switch in the back line distribution block for the brake lights.

Mounting the combo could be a lot cleaner if you take the time to make brackets that look better. I got this idea from a picture I found on the net. They had used two pieces of square tubing to space the booster out, this does look cleaner. I used 4 short pieces to make it a little easier. Spacing out the booster is necessary because the booster push rod and the tube nut length is too long.

I cut the old push rod and welded it to a tube nut that fits on the new master cylinder and cut the old brackets off the old booster and mounted the new booster on them. Tube nut thread size is 3/8 X 24 for this application.

The 8" booster clears the shifter arm by about an inch. Everything else is factory.

Total cost was about $200.

YellowRose
08-28-2017, 01:13 AM
Hi Iffy! I see you figured out pic posting! Congratulations! What I do not see is a combination valve installed in your dual MC/Dual Booster system. It has always been my understanding that you need one in that installation. In fact, if you put one in and do the wiring off it, you can keep that Gen light working.. But that might only apply if you also have front disc brakes. Do you? I also see that either the original color of your Tbird was not Raven Black but Red. Or sometime in the past, had been painted red... Here are a couple of pix showing the combination valve, and my installation with front disc brakes. That Chrome set up only cost me $25 more over the normal version! My air cleaner, valve covers, VR, oil cap, are all chromed...

Infinite Monkeys
08-28-2017, 01:24 AM
Hi Iffy! I see you figured out pic posting! Congratulations! What I do not see is a combination valve installed in your dual MC/Dual Booster system. It has always been my understanding that you need one in that installation. In fact, if you put one in and do the wiring off it, you can keep that Gen light working.. I am sure Dave or John will probably comment on this also. I also see that either the original color of your Tbird was not Raven Black but Red. Or sometime in the past, had been painted red...

Hi Ray,
You are correct, I do not have a combination valve, it wasn't necessary for a drum/drum setup. My gen light is still functional.
I had to put in a combination valve for a hydro-boost system I did for my '71 Bronco, but that is a disk/drum. Disks need a residual valve that wasn't in the MC, plus it allows you to adjust bias between front and back.

I'm not sure what that color is, but I like it. Kind of an orange?

Infinite Monkeys
08-28-2017, 01:35 AM
Sorry,
I got combination valve and proportioning valve mixed up. The one I used is a combination of both. I think they are necessary if you have disk brakes or a disk/drum combo.
My brakes work without the valve.

YellowRose
08-28-2017, 01:36 AM
If that was the original OEM red color, it would have been Monte Carlo Red on a 1960 Tbird... Unless someone painted it another color from another year. I see your set up is a drum/drum and that you do have your Gen light still working, which is good.

Buckaroo
09-05-2017, 11:53 PM
Could a person use this to replace the under dash unit on a 58?

simplyconnected
09-06-2017, 12:32 AM
...My brakes work without the valve.Herein lies a big problem.

You have a modern M/C with two pistons on a common shaft.

IF both front and rear systems require exactly the same amount of brake fluid, your brakes will seemingly work just fine. But, what happens when one system (usually the front) wears down more than the other system? The one worn down more will require more fluid and the brakes will only advance as far as the system that stops first.

I hope you understand, as long as all your brake shoes are always adjusted to the drums your system will seem to work ok.

A combination proportioning valve COMBINES both systems by a common piston between them. The fluids never mix but mechanically, they are tied together. If one system's shoes hit the drums first, the piston moves toward the side that has lower pressure. This equalizes both system pressures while the flow is at liberty to be different. If the disparity becomes excessive, the valve turns on a switch, which indicates a brake problem.

The combination proportioning valve for drum/drum (or disk/disk) is the same valve as disk/drum except the pressure reducing portion is gutted.

If you use self-adjusters on your brakes there is no reason for a residual valve. I personally don't like residual valves because they can cause the wheel cylinder pistons to extend so much, they pop out of their bores. This was common on Tempo cars.

I suggest you invest in a combination proportioning valve because believe me, you need it. That's why ALL cars come from the factory with one.

Could a person use this to replace the under dash unit on a 58?Yes, but you need a firewall bracket that extends the new booster up five inches and out (from the firewall) five inches. - Dave

Infinite Monkeys
09-06-2017, 12:49 AM
Dave,

Thanks for that extremely informative post. I am looking for the right valve right now and will plumb it in before I drive the car again.

Not taking any chances with the braking system.

simplyconnected
09-06-2017, 06:42 AM
I suggest this PV4 valve: CLICK HERE (http://piratejack.net/gm-disc-disc-proportioning-valve-brass/) Call their number to make sure this valve is also used for drum/drum applications.

I like it because the mounting holes are part of the casting. 1/4"-20 bolts fit. Most of us mount the valve on the fender apron, then plumb to it. The M/C brackets use space under the M/C, making it harder to change spark plugs. If you mount to the fender apron, the valve is out of the way but still very accessible.

Here's an internal view...

sidewalkman
09-12-2017, 05:29 PM
I suggest this PV4 valve: CLICK HERE (http://piratejack.net/gm-disc-disc-proportioning-valve-brass/) Call their number to make sure this valve is also used for drum/drum applications.

I like it because the mounting holes are part of the casting. 1/4"-20 bolts fit. Most of us mount the valve on the fender apron, then plumb to it. The M/C brackets use space under the M/C, making it harder to change spark plugs. If you mount to the fender apron, the valve is out of the way but still very accessible.

Here's an internal view...

So can someone with Drum/Drum use disk / disk?

Infinite Monkeys
09-13-2017, 01:27 AM
I was unable to find a drum/drum valve. Looks like no one makes it. I could not get an answer to using a disk/disk one instead.

YellowRose
09-13-2017, 01:36 AM
Iffy, hopefully, someone will come along and answer your question. I do not know the answer....

Infinite Monkeys
09-13-2017, 01:58 AM
I found this article online.Seems to describe brake pretty well.
The thing that doesn't make sense is that our cars did not come with a proportioning or metering valve. (not that I know of, I currently don't have one, but that doesn't mean there wasn't one from the factory)
I had a '71 Scout II some years back. It had drum/drum with dual piston master cylinder. It had a distribution block with a switch from factory. The block's purpose is to activate a warning light if there is a failure in the braking system.


http://mbmbrakeboosters.com/index.php?option=com_content&view=category&layout=blog&id=8&Itemid=16

simplyconnected
09-13-2017, 07:09 AM
...The thing that doesn't make sense is that our cars did not come with a proportioning or metering valve... ...The block's purpose is to activate a warning light if there is a failure in the braking system...Squarebirds were manufactured before dual-piston master cylinders were around. A single piston M/C has only one hydraulic circuit for all four brakes so proportioning and metering is impossible.

The distribution valve (I don't like to use the term, 'block') separates the two hydraulic circuits with a common piston. Yes, you get a warning switch but most folks never wire it. (This is a problem.) A valve with a floating piston between both circuits makes all the difference because both circuits RARELY use the same volume of brake fluid. The floating piston allows one side to stop flow (because the brake is tight) while the other side continues it's flow. The side that is tight simply moves the piston toward the lower pressure side until both sides have equal pressure.

In a dual-piston M/C setup, both pistons deliver the exact same volume because they are on the same spool. Without the valve, the brake circuit that applies pressure on the drums first would prevent the other brake circuit from advancing any further. Our rear wheel cylinders are smaller in diameter than the fronts, so they would lock up first. The only remedy would be to keep the rear shoes far away from the drums in a mis-adjustment fashion so the rear pistons would travel farther. This would allow the front cylinders to fill their larger-bore cylinders before the rear drums lock. No, I'm not suggesting anyone follows this crazy scheme, I am suggesting, if you have a dual-system brake setup, YOU NEED a valve (not an empty block with all the internal ports connected) with a common floating piston between both circuits.

To answer your question directly, YES, you can use the same valve on drum/drum OR disk/disk systems. The insides of a disk/disk valve do not alter or proportion pressure between front and rear circuits. I recommend using a combination valve BECAUSE:
A combination valve will offer metering which applies rear brakes first, then the front, then both. This is good on wet leaves or loose stones, ice, snow, etc.
If one circuit is ruptured, a combination valve will shut off the leaking circuit so all the fluid isn't drained.
The electrical switch indicates a very dangerous situation. Unfortunately, no valve can anticipate ahead of time so the alarm shows the fault already exists.


A disk/disk valve is VERY common. Recognize that it is also for a drum/drum application. I like and I use MBM products on my disk conversions. - Dave