Has anybody used this proportioning valve?

[qkcuda]

Has anybody used this Summit brand proportioning valve? I am ready to put in an order and I am considering it. I am open to other suggestions available through Summit. Since I am in Canada, I want to combine my order to take advantage of their cheap shipping.

I have to admit the instructions are somewhat confusing. Do you actually need to use the second metering valve?

 

[gkent]

You don't need anything more than an aftermarket adjustable brake proportioning valve. That part that has the wire terminal on it is a useless item - all it does is turn on you brake warning light when you have a COMPLETE brake failure ... like you need a light to tell you that !!!

 

[Beekeeper]

that unit is sold by inline tube and if it’s anything like the rear proportion valve they sell i don’t think you will he happy with it.
Take the advice from @Stanton and just purchase an adjustable valve and install in the rear line between master and rear cylinders.

 

[qkcuda]

What do you think about this one? It was actually my first choice, but then I wondered if I should use something more stock looking. I will be running a late model two bolt master and this one has a bracket that mounts on the two studs and it should simplify running my brake lines considerably.

 

[wagonman]

I have used the Summit Adjustable 2 port valve with a Disc- Drum system. One line in one out with the dial. Easy Peasy.

 

[RemCharger]

I agree with the replies and add.. just run a line to the rears.
Just run a line to the fronts with a tee.
The cars I've put adjustable valves in , ended up working well with them wide open.
If you can actually create a rear lockup situation, then install an adjustable.

 

[Beekeeper]

What do you think about this one? It was actually my first choice, but then I wondered if I should use something more stock looking. I will be running a late model two bolt master and this one has a bracket that mounts on the two studs and it should simplify running my brake lines considerably.

View attachment 1317919

yea that one has un needed ports all you need is an in and out. something like this
one

 

[qkcuda]

Thanks for all of the responses. I had another look under the car. I currently have the single pot master. It has a distribution block on the frame rail. It looks like I can plug the rear outlet and run a line from the front master port into it and reuse the factory front lines. I will get the single adjustable proportioning valve and plumb it into the rear line only.

View attachment 1318034

 

[Ceedawg]

The ‘proportioning’ valve goes to the rear brakes not the front. The big piece shown is nothing more than a safety valve, like factory, in case you lose front or back brakes. If your back brakes grab or lock up then you need a p valve or smaller diameter brakes.

 

[Dragon Slayer]

What car is that on? You said single pot mc. That is just distribution block with no warning light. If you spring a leak, you loose all brakes. Only one reservoir.

You probably want to go to a 67 set up with dual reservoir MC and just basic distribution block with warning light.

Unless you move to Disc brakes in front, you do not need a proportioning valve, nor do you need a metering valve which was specific to the front disc. Also called hold off valve.

The 70 service manual will describe what they did for the 1970 KH disc set up.

 

[gkent]

What are you doing with the rest of the brake system ... converting to front discs, etc ??

 

[qkcuda]

Yes, the car is a 1966 Charger, and I am converting from the stock drum brakes and single pot master to front discs and a modern two bolt master. I bought the Scarebird conversion kit which utilizes the stock spindle and hub. I was able to source all of the brake parts locally. I was going to use a combination valve I had left over from a previous car, but it is the large GM style. The single proportioning valve will make a much cleaner and easier installation. My car doesn't have provision for a brake warning light anyway.

 

[qkcuda]

I placed my order with Summit today. I bought their Summit brand proportioning valve which looks identical to the Wilwood one pictured above. Thanks again for all the help.

For what it is worth all of the Summit branded parts on my order were 10% off.

 

[Tinker67]

You don't need anything more than an aftermarket adjustable brake proportioning valve. That part that has the wire terminal on it is a useless item - all it does is turn on you brake warning light when you have a COMPLETE brake failure ... like you need a light to tell you that !!!

Proportioning valve has a distinctive job, it lets you know when you have a failure between frt. or rear brakes. If one fails you still have stopping power from the other, the light comes on. May not be what you were expecting , but you still have some braking. Now it's very unlikley that you would have simultaneous failure between frt. and back, and even if you did the light would 'NOT' come on due to equal pressure at the switch that you say is useless. I have been contemplating posting this since the weekend ,now is the TIME . Some folks don't know, that's why they ask, so when you speak you should tell it like it is

 

[Beekeeper]

Proportioning valve has a distinctive job, it lets you know when you have a failure between frt. or rear brakes. If one fails you still have stopping power from the other, the light comes on. May not be what you were expecting , but you still have some braking. Now it's very unlikley that you would have simultaneous failure between frt. and back, and even if you did the light would 'NOT' come on due to equal pressure at the switch that you say is useless. I have been contemplating posting this since the weekend ,now is the TIME . Some folks don't know, that's why they ask, so when you speak you should tell it like it is

The proportioning valve reduces pressure to the rear brakes the part you speak of is called a distribution block two
different functions. The later blocks are combination valves with the proportioning valve built in.

 

[Ceedawg]

The proportioning valve reduces pressure to the rear brakes the part you speak of is called a distribution block two
different functions. The later blocks are combination valves with the proportioning valve built in.

Exactly what the teachers said at the Dodge technical classes back in 1970. TY

 

[Nxcoupe]

Proportioning valve has a distinctive job, it lets you know when you have a failure between frt. or rear brakes. If one fails you still have stopping power from the other, the light comes on. May not be what you were expecting , but you still have some braking. Now it's very unlikley that you would have simultaneous failure between frt. and back, and even if you did the light would 'NOT' come on due to equal pressure at the switch that you say is useless. I have been contemplating posting this since the weekend ,now is the TIME . Some folks don't know, that's why they ask, so when you speak you should tell it like it is

It's actually called a differential pressure valve, which moves to the area of low pressure blocking off the line that has lost pressure allowing the other circuit to maintain pressure. Installing a dual master cylinder without this valve does you absolutely no good. One line breaks and you aren't stopping. A metering block has that diff press vlv in it along with others depending on application, ie, residual pressure valve, proportioning valve or brake pressure hold off valve, or a combination of all of them. Hope this helps. I'm buying the metering block pictured for mine, it does have a differential pressure valve in it according to the manufacturer.

 

[Dragon Slayer]

That is not how it works. If it did you would not need a dual chamber MC. The distribution block is what Chrysler calls it. It ports the MC output to the various brake lines. After 67 federally dual chamber mc were required. The distribution block has a valve with orings on it that can move off center to the lower pressure. When it does it contacts the sending unit and provides a ground for the brake light indicating a problem. Which ever side lost pressure continues to loose pressure and you have no brakes for that system. The other system has full pressure. So you may loose rear brakes or you may loose front. But you don't loose both. Internally the MC has two pistons and if one collapse because of fluid loose it has stop built into the piston and ultimately stops moving. The other piston is isolated but connected. It can continue to move and build pressure.

The proportioning valve actually acts normally with pressure in front and rear the same until a preset pressure. Usually around 250-300psi, at that point it act as an orifice/relief and pressure rises at 50% of the input pressure. So lets say 300 psi set point, if line pressure is 600psi that is what front sees. The rear sees 300 plus 50% of the last 300, so 450psi. Front goes to 900 psi rear goes to 600psi. Meter valve for KH just holds off pressure on the front to allow the rear to start engaging. Again at a preset pressure for the system. Bendix on b bodies before 69 did not use the Hold off/Meter valve. 70 KH for the B/E did.
Read the 70 service manual in chapter 5. Does a good job explaining. Then read the Master training on brakes (can find on web) and you will fully understand the system.

 

[Nxcoupe]

That is not how it works. If it did you would not need a dual chamber MC. The distribution block is what Chrysler calls it. It ports the MC output to the various brake lines. After 67 federally dual chamber mc were required. The distribution block has a valve with orings on it that can move off center to the lower pressure. When it does it contacts the sending unit and provides a ground for the brake light indicating a problem. Which ever side lost pressure continues to loose pressure and you have no brakes for that system. The other system has full pressure. So you may loose rear brakes or you may loose front. But you don't loose both. Internally the MC has two pistons and if one collapse because of fluid loose it has stop built into the piston and ultimately stops moving. The other piston is isolated but connected. It can continue to move and build pressure.

The proportioning valve actually acts normally with pressure in front and rear the same until a preset pressure. Usually around 250-300psi, at that point it act as an orifice/relief and pressure rises at 50% of the input pressure. So lets say 300 psi set point, if line pressure is 600psi that is what front sees. The rear sees 300 plus 50% of the last 300, so 450psi. Front goes to 900 psi rear goes to 600psi. Meter valve for KH just holds off pressure on the front to allow the rear to start engaging. Again at a preset pressure for the system. Bendix on b bodies before 69 did not use the Hold off/Meter valve. 70 KH for the B/E did.
Read the 70 service manual in chapter 5. Does a good job explaining. Then read the Master training on brakes (can find on web) and you will fully understand the system.

View attachment 1325762

Have you ever had a master cylinder fail on one circuit, without a functioning differential pressure valve? let me know how well it stops. The differential pressure valve moves to the area of low pressure, blocking that circuit off, this allows the piston that lost pressure to now maintain pressure, pushing the piston in front of it forward, if it is reversed, it allows the rear piston to keep from over extending, allowing the pedal to go to the floor. You believe as you wish. We may be saying the same thing in a different way. You can see the piston that moves to block the flow of fluid through the circuit in the exploded view above. No it doesn't loose pressure, as when you push on the brake pedal, it blocks the circuit off, allowing you to press and apply the brakes.
And it can't function without a dual master cylinder, it requires the 2 chambers both pushing fluid to equalize it. Both of these things were mandated in 67, the dual master cylinder and the differential pressure valve. You have to have both, so I'm not understanding what your point is with that.
And on today's vehicles all these valves are built into the ABS unit now.

 

[Dragon Slayer]

Have you ever opened one to repair, rebuild or inspect it? I just reexamined the one I have on the bench. First, the hourglass slug only moves a small amount before it contacts the warning switch. Hard stop of movement. So the piston only moves a small mount. The springs keep the pistons against the slug and centered when there is equal pressure on both sides. While the plug can move towards covering the port, the piston diameter is much smaller than the bore and does not seal the ports. It just does not move that far and has too much clearance. It would be like trying to use a master cylinder without the seals on the piston. The 2 Orings just isolate the front and rear circuit inside the distribution block. BUT THEY provide no closing of a port if pressure is lost on one side.

None of the service manual or training manuals talk to what you're saying. Makes sense to do it and modern cars may, but the distribution block on these vintage cars don't. No ABS involved here.

If you don't believe me crack one of the lines loose on the distribution block and push on your pedal. You will have stopping power on the sealed circuit, but you will keep pushing fluid out of your loose fitting until that reservoir on the MC runs dry. It just does not work how you're saying. Sorry.

PS Infact if it worked your way, you could never bleed brakes by using pedal, the piston would close it off. But you can bleed brakes by pumping pedal because the piston can't seal the port.