Adjustable proportioning valve

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mopowers

mopowers

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I've got a 68 Dart with the stock 4-wheel drum prop valve, from what I understand is nothing more than a distribution block.

I just completed a front disc conversion on the car and plan on plumbing in an adjustable proportioning valve. Does the Proportioning valve need to go after the stock distribution block, or does it matter?
 
Been there ... with questions and doing same thing .. IF you are using Kelsey hayes system .. you need to install front block for disc brakes and then a smaller block directly after ... you can get these at inline tubing ...
 
I'm using 73- brakes if that matters. It was my understanding that I can just plumb in an adjustable prop valve to the rear brake lines and be done with it.
 
73 what brakes ... Kelsey hayes ? .. big bolt pattern ... ? sbp ?
I guess that will work .. but i am trying to achieve the factory look ...
 
I eliminated the distribution block altogether when upgrading to BBP all around. Just ran a line from the aluminum M/C front brake port, to my new line-loc, (preparing tor future 4 speed conversion) then into a simple tee, then to each front brake. (73-76 A body discs)

Ran a line from the rear brake port into an adjustable prop valve (Summit but looks exactly like a Wilwood, then into the line leading to the rear brakes. (10" B-Body drums)

The "safety valve" does nothing more than turn on the red brake light in my 68 cuda dash in case of a hydraulic leak. That function is gone but so what. After doing all that, I had a minor leak that I immediately sensed by the brake pedal moving ever so slowly toward the floor when applying and holding the brakes. It was so small I had a hard time locating it but all it took was cranking one of the fittings a little more. Now I self-check them whenever I take the car out. Push hard on the pedal and hold for about 10 seconds. If no movement in the brake pedal, I'm good to go (and stop).

I like simple systems and reliability over anything. The fewer the hydraulic joints and parts, the less things to go wrong. Running a 1-1/32" bore aluminum M/C w/o power.This is a driver and the pedal is rock hard and feels linear.

This may not be for everybody, but it suits me.
 
KosmicKuda said:
I eliminated the distribution block altogether when upgrading to BBP all around. Just ran a line from the aluminum M/C front brake port, to my new line-loc, (preparing tor future 4 speed conversion) then into a simple tee, then to each front brake. (73-76 A body discs)

Ran a line from the rear brake port into an adjustable prop valve (Summit but looks exactly like a Wilwood, then into the line leading to the rear brakes. (10" B-Body drums)

The "safety valve" does nothing more than turn on the red brake light in my 68 cuda dash in case of a hydraulic leak. That function is gone but so what. After doing all that, I had a minor leak that I immediately sensed by the brake pedal moving ever so slowly toward the floor when applying and holding the brakes. It was so small I had a hard time locating it but all it took was cranking one of the fittings a little more. Now I self-check them whenever I take the car out. Push hard on the pedal and hold for about 10 seconds. If no movement in the brake pedal, I'm good to go (and stop).

I like simple systems and reliability over anything. The fewer the hydraulic joints and parts, the less things to go wrong. Running a 1-1/32" bore aluminum M/C w/o power.This is a driver and the pedal is rock hard and feels linear.

This may not be for everybody, but it suits me.
Click to expand...

I hear ya on the simplicity. It's just, my cars already plumbed, so if all I have to do is plumb in a prop valve and be done with it, that's all I've gotta do to be on the road.
 
IF you have the entire brake setup including the distribution block from a '73 then it almost certainluy is a combination block w/ proportioning valve.

You can find descriptions in the Master Technician's Conference booklets f
try 1972 Disk Brake Roundup vol 72-05
and then look in '73 for updates.
http://www.imperialclub.org/Repair/Lit/Master/index.htm

If you are using the 1968 distribution block, then you need to add a proportioning valve in the line going to the rear.

An original prop valve for '68 is not adjustable. If you want adjustable you can get one for an early Mustang/Corvette kelsey hayes system, or from Wilwood, Mopar Performance etc.
 
I'm with you Mopowers, I'm doing this on my 68 and think the donor proportioning valve is bad. The adjustable ones are $35 and the best price on a new 73 one is over $100. I would think you add it after the block in the rear line but I too would like to know for sure and see some pics of where to point the knob.
 
How do you set the adjustment for the rear brakes?
 
I think just trial and error in a parking lot or on some loose surface until you get even lockup.
 
One more way to make your mark I guess :)

Not as fun as the other way :burnout:
 
Mattax said:
IF you have the entire brake setup including the distribution block from a '73 then it almost certainluy is a combination block w/ proportioning valve.

You can find descriptions in the Master Technician's Conference booklets f
try 1972 Disk Brake Roundup vol 72-05
and then look in '73 for updates.
http://www.imperialclub.org/Repair/Lit/Master/index.htm

If you are using the 1968 distribution block, then you need to add a proportioning valve in the line going to the rear.

An original prop valve for '68 is not adjustable. If you want adjustable you can get one for an early Mustang/Corvette kelsey hayes system, or from Wilwood, Mopar Performance etc.
Click to expand...



I've still got the stock 68 drum-drum distribution block. And instead of buying the 73-up disc/drum valve, I just decided to keep the system the way it is and install the adjustable prop valve in the rear line. I'd just like to see some mounting ideas for people who mounted their's on the frame down stream of the factory drum distribution block. Is there a specific way the knob need to be oriented?
 
Orientation is mostly about how you can make it hook up to the lines, and your preference for access. I don't adjust it that often but it is nice to be able to get to it from the top (engine compartment) rather than sliding underneath.

Testing on slick surface is correct. If you find the rear locking up before the fronts, adjust it until its the same or the fronts lock up first. Imagine what happens to the car on a wet down hill if the front brakes are working and the back locks up. The back of the car then continues at a higher speed than the front!

If you change to stickier tires, or you get more skillful in braking on the track or autocross, you may find the need to adjust. Why? With more effective braking there is more weight transfer to the front. That means more wieght off of the rear, making it easier to lock up the rears.

PS. My preference was to buy premade double flared brake line in the length I wanted. Instead of cutting the existing line, you may have room to make a strain relief. At some point you may have to make double flares, it just takes practice but if a shop or a buddy has the good flaring tools, that's a big help.
 
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