Brake question

[SF-66TC]

I can not get any information from the last owner as to what he switched and from what years the parts are from. I believe it was a single circuit manual drum/drum, there is no wire going to that area for the switch, and no brake warning light inside. Could a wire be added from my valve switch to my parking brake light on the inside
I am still uncertain as to what I have ,is it a distribution block or a proportioning valve. If it is just a distribution block then I could add a proportioning valve. If it is already a proportioning valve ,then I will just add the disc/drum master cylinder

Does a proportioning valve go after the distribution block or before it

Looking over your photos and description I assume your car originally came with Power Brakes, Single Master Cylinder, Single Distribution Block (like my attached photo) and drum/drum brakes.



The PO then -

1. upgraded the front drums to disc brakes
2. installed a drum/drum master (looks to be the A1-Cardone 101323 which is wrong for your setup)
3. and changed the original distribution block to a later model type when he did the change from a single circuit master to a dual circuit master
4. That also explains why the current distribution block has the warning light switch on it and your car does not have a hook up for it.

So again -

1. change the master cylinder to the correct disc/drum mc
2. install a prop valve
3. DONE

 

[kenmdale]

I believe the PO started off with manual brake single circuit, then switched to power brakes with a tandem brake booster for drum/drum and installed the distribution block at that time. then upgraded to disc brakes later. I have the M/C on order and will be switching that over soon . I will be ordering a proportioning valve tomorrow.
My confusion was that I had people tell me that I did have a proportioning valve in it. (as in the photo earlier )


Thank You for your help

Ken

 

[SF-66TC]

I believe the PO started off with manual brake single circuit, then switched to power brakes with a tandem brake booster for drum/drum and installed the distribution block at that time. then upgraded to disc brakes later. I have the M/C on order and will be switching that over soon . I will be ordering a proportioning valve tomorrow.
My confusion was that I had people tell me that I did have a proportioning valve in it. (as in the photo earlier )


Thank You for your help

Ken

Sorry, I can say with 100% certainty what your valve is. Mopar parts were usually "brass blocks" - yours is obviously different. If you question whether what you have is a prop valve or not, just change the M/C and see how your brakes feel. Do a couple panic stops. As I've researched, the factory did NOT install prop valves in the earlier disc brake cars so essentially the engineers didn't feel they were necessary.

Here's a nice video explaining - https://www.youtube.com/watch?v=pUZgY8CJCCE

Good Luck!

 

[70bigblockdodge]

Got it. I agree put the disc/drum mater cylinder on do some panic stops in a open area/parking lot. Ideally the fronts should lock first to prevent a spin, as long as the rears don't lock till you are really pushing hard on the pedal you are close and should be fine except for the worst of situation and most likely as good as factory car. If you want to refine it further you can only benefit, put by all means get rid of that drum drum m/c it may run out of fluid on the disc side before pads are worn out.

 

[commando1]

Might I add that after doing panic stops to check for front brake lockup, that testing only the rears with the e-brake be done to be sure you indeed also have the rears working.

 

[SF-66TC]

I believe the PO started off with manual brake single circuit, then switched to power brakes with a tandem brake booster for drum/drum and installed the distribution block at that time. then upgraded to disc brakes later. I have the M/C on order and will be switching that over soon . I will be ordering a proportioning valve tomorrow.
My confusion was that I had people tell me that I did have a proportioning valve in it. (as in the photo earlier )

Thank You for your help

Ken

Ken,

I contacted Rick Ehrenberg, showed him your photo and asked him what he thought you had.

Rick's reply:

"Looks like a prop and metering, "combo valve". Being the later iron version, I'd be amazed if it functions!"

Me:

"Would you agree that it would be best to just disco the m/c & brake lines to the valve, plug the two ports and add a prop valve in line with the m/c & rear brake line?"


Rick's reply:

"Yes, for sure. Just keep the front and rear circuits totally isolated"


That said you got an answer from the expert!

 

[commando1]

If E-booger said the Earth was flat, then I would take it as gospel that the earth was flat.

 

[70bigblockdodge]

The earth is flat.

 

[commando1]

I don't believe you...

 

[kenmdale]

Cheers ,Thanks for your help, at least now I know what that part actually is . I will replace with proper parts.
With this heavy a car ,I want to make sure it will stop

 

[70bigblockdodge]

I don't believe you...

I will work on my rank.:sSig_thanks:

 

[Snotty]

I think okay to keep booster on a dual system car. His is originally a single circuit car. I am not 100% on that so don't go completely on my word.

Ah, hadn't thought of that. I would guess that would, indeed, make a difference.

 

[kenmdale]

Ive completed the changeover. I was able to find a Bendix Dual Diaphragm Booster and the proper master cylinder for a front disc/rear drum brake setup. I was able to keep the metering/proportioning valve. I had to go through 3 master cylinders before I found one that didn't leak through the main piston, the first 2 were new, the third one was a rebuilt one.
I found out that the master cylinder had different thread for the drum brake section ( 9/16-18 thread for a 1967/68 Fury). The thread fitting for a 1969/70 Fury has a 9/16-20 thread for the drum brake section of the master cylind


I would like to thank all that have helped out. I've found it difficult to track down parts for the car ,when I'm not sure of the different years of the parts have been used by the PO. It turns out that the disc brake system including the brake valve were from a 1972 Fury ( as someone mentioned earlier in this thread)
I thought I would finish this thread. its a pain to read through pages of posts ,then find there is no final resolution to a problem

Merry Christmas

Ken

 

[cantflip]

Kenmdale: I believe what you have there is nothing more than a distribution block for the front & rear brake lines. The small nipple in the middle of the two incoming lines from the master cylinder is the "idiot light" switch that turns on when it senses a pressure differential between the front and rear.

Here is a generic explanation of a combination valve. Also most pressure differential switches will block the flow of brake fluid on the failed circuit to slow the emptying of the master cylinder and prevent you from pumping only air with that piston. the light feature was kind of silly, but federally mandated and does let the next driver know of a problem.

I hope this clears up any confusion...

A three function combination valve contains the proportioning valve, metering valve, and a pressure differential switch in one convenient location. The combination valve is typically located on the firewall. A two function combination valve omits either the metering valve or the proportioning valve. Let's have a look at a three function combination valve.
Metering Valve: The metering valve is in charge of delaying the application of the front brakes just long enough to overcome the rear brake springs. It's installed on vehicles with front disc rear drum braking systems. When the brakes are first applied, pressure quickly overcomes a spring in the valve and closes a port to the front brakes. This temporarily reduces fluid pressure. When the pressure builds to a predetermined amount (75-100 psi.). After this brief delay, pressure to the front calipers is returned to normal. When a metering valve fails, the vehicle's front brakes apply early and the tends to nose dive.
Proportioning Valve: The proportioning valve is used to prevent rear wheel lock-up. These valves achieve balanced braking by reducing fluid flow and pressure to the rear brakes during hard and sudden stops. It activates only during hard and panicked stops. Most of the time during light and moderate braking the valve lies dormant.
Pressure Differential Switch: The pressure differential switch is used to inform the driver if there is a leak in the system. It is used in dual master cylinders to detect a difference in pressure between the two sides. If there's a difference in pressure, the switch will complete the circuit and illuminate the red brake warning indicator lamp.