what is this

[1930]

The car ( 67 falcon ) had been converted to disk brakes in the front before I got it, Ive put them now in the back as well and am running all new line but doing a google search on proportioning valve versus dist block I can see the differences so Im not sure what I have here and so what I may need if anything else.

Im assuming my master cyl will be just fine.

EDIT: Ok doing a google search I see that the consensus today ( that may change tomm. ) is no proportioning valve is needed and Im really thinking this block is just a dist block.

 

[dbabicky]

Yep. Distro block.

 

[Ole Slewfoot]

I'm pretty confident that thing is just a home for the failure sensor, but its been a long time since I had my '66.

 

[jimindm]

Can not really say what you have in picture one. It may be either, and they may be the same part just some one is calling them a different name.

What that picture shows is the valve that will transition over to just half of the brake system working in a catastrophic pressure drop.

A braking system generally applies some rear brake first, and then the fronts come on as the back build up pressure. This can be done many ways. Smaller calipers on one end, valving in the MC, some type of valving that you show in picture one.

In most production cars the manufacturers choose not to change much in the way of lines between systems. They may change the master to get more fluid flow needed for calipers, but the plumbing is sort of all the same.

You do not say if these parts came off of the car. I would think the MC maybe different for a caliper system. The one pictured does seem to have the same size chambers, but who knows about the valving inside.

Are you going with a complete aftermarket kit? If so you may have valving in the MC to do away with the block. If you are using production pieces and it looks like you are I would guess it should be included.

I would say in the era of vehicles you are working with,the brake system was the most complex system and the least understood. Lets face it most never use it to its full potential, until a panic stop is needed. Most of the time I would bet that the system never used but about 40% of its ability. That is just the way most people drive.

On the engineering side, a braking system is way over built for for what is does in most cases. It is the few cases that you want the full use of it when it is needed.

 

[rockettgpw]

The first pic is of a fluid leak indicator switch. The master cylinder on the right has two chambers, one for front brakes and one for rear. The front brake path and the rear brake path are separated from each other in this block on the left. There is a piston under the plug on the right that will travel toward the end with the leak. The switch in the centre top has a plunger that drops into a groove on the piston and then switches on the "brake" indicator light on the dash. It is not a proportioning valve, IME they need a lever attached to the frame for "tilt" reference.
Later (1970ish) falcons had that switch in the master cylinder which made for tidier piping.

 

[Tim C]

Ive got a 67 Fairlane which is the same basic chassis as the falcon. That pic is just a distribution block and switch if one side loses pressure. The proportioning valve on these cars is a small cylinder shaped piece you can see from under the car. Follow the rear steel line along the transmission tunnel, up where the floor transistions into the firewall is where it was on my car, to the right of the Bellhousing. The residual valves which hold a slight bit of pressure in the line to keep wheel cylinders from leaking and the shoes held out slightly are in the master cylinder where the brake lines attach stock. Ive left them alone on a few cars that were converted to disc with no ill effect. Lots of reman master cylinders are missing them already so you may not even have them.

Other vehicles, especially GM cars and trucks had all three of these valves in one unit, commonly called the proportioning valve, but a more accurate name which it is referred to in service manuals as is the combination valve.

Sent from my HTC6545LVW using Tapatalk

 

[texasprd]

^^^ THIS ^^^

I went through this back when I was in college. I converted the drum brakes on my '72 Comet to disks "donated" from a '68 Cougar. I have heard the "proportioning" valve that Tim mentioned also referred to as a "delay" valve. I think I have an extra proportioning/delay valve in the garage - I'll try to post a pic tonight if time and memory allow.

I can tell you from experience that you want to be sure that you have the MC for a disk-brake car - I believe there is a difference between disk-brake and dual-circuit drum-brake master cylinders. Also check for differences in the brake pedal - I believe they are the same but check for yourself. For me, the differences is master cylinders became apparent at the drag strip when I went through the lights at 107 MPH and almost went off the shut-down area because the car wasn't slowing down fast enough! That was 30+ years ago and I still remember thinking "COME ON, BRAKES!!!!"

 

[6768rogues]

The master is ok as long as they used a disc/drum master. Drum brakes have a residual pressure valve in the master to hold some pressure. That pressure helps to overcome the pressure of the return springs on the drum brake shoes. Discs don't have return springs, so no residual pressure valve. Sometimes the valve can be removed from a drum master.
I tried a disc/drum master on a drum/drum vehicle and it would not stop quickly even if I put both feet on the brake pedal. That residual pressure is important to drum brakes. Used on discs, the discs will never fully release.