Valve question

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Diesel0081

Diesel0081

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I'm doing a drum to disc conversion on a 73 Dodge Dart. The spindles and everything I got are off a 73 or 74 Duster... My question is, the prop. valve on my Dart looks exactly the same as the prop. valve that came off the Duster. I figured they would different on a drum brake car than a disc brake car. Is it internaly different or did they use the same valves on both. I have a pic of the one that came off the Duster.
 

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The valve in the picture really doesn't match up to what a "DISC BRAKE"
proportioning valve looks like, when you compare them.
If it's of help to you, here is a photo of what a "A" body disc brake prop valve looks like.
Install the disc brake one, when the time comes.

Are you sure everything off your donor car is original to it?
Meaning, all the disc brake components?
Looks to me, your donor car prop valve, is a regular drum brake one already.
 

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hemi71x said:
The valve in the picture really doesn't match up to what a "DISC BRAKE"
proportioning valve looks like, when you compare them.
If it's of help to you, here is a photo of what a "A" body disc brake prop valve looks like.
Install the disc brake one, when the time comes.

Are you sure everything off your donor car is original to it?
Meaning, all the disc brake components?
Looks to me, your donor car prop valve, is a regular drum brake one already.
Click to expand...

Well I know everything came off the same car, and the car had disc brakes. I got the spindles, caliper brackets and the valve off same car. So it would seem strange that it would have a drum prop valve...
 
Your already questioning wether the donor car one is the same that's on your car now.

That's good that your comparing the parts before you tear into everything.

When i first viewed your picture, the first thing that came to mind was, i never have seen an A body disc brake prop. valve that looked like that before.

That's why i dug the photo out of my computers files, of some past disc brake set up's that i have sold in the past, on and off eBay, and found lots of photos of prop valves and the lines.

Guess it's going to be your decision to install the one that you removed from the donor car.

Possibly some others might respond to your posting, with their thoughts between drum and disc valves, what they look like.

Anyway, happy wrenching, when installation day comes around with all your parts.

 
hemi71x said:
Your already questioning wether the donor car one is the same that's on your car now.

That's good that your comparing the parts before you tear into everything.

When i first viewed your picture, the first thing that came to mind was, i never have seen an A body disc brake prop. valve that looked like that before.

That's why i dug the photo out of my computers files, of some past disc brake set up's that i have sold in the past, on and off eBay, and found lots of photos of prop valves and the lines.

Guess it's going to be your decision to install the one that you removed from the donor car.

Possibly some others might respond to your posting, with their thoughts between drum and disc valves, what they look like.

Anyway, happy wrenching, when installation day comes around with all your parts.
Click to expand...

Yeah, I think I'll get the other stuff done first... Hopefully I can get some more input and decide then...
 
WHAT MODEL YEAR is your original car, and I assume it has drum brakes?


The valve pictured IS NOT a proportioning valve. It is quite simply a distribution block with the warning light switch. The switch consists of a simple piston which is normally centered, with the switch OFF. IF one "end" or the other loses pressure, the piston "shuttles" to one side, triggering the switch.

This thread:

http://www.forabodiesonly.com/mopar/showthread.php?t=134889

The photos below clearly show that at least some cars use SEPARATE prop. valves I found one drawing that seems to indicate that some cars used a 1 switch, 2 a metering valve, and 3 a prop valve in the same car.

These drawings are out of the 67 and 69 shop manuals:

sd0b3n.jpg


98aqlw.jpg


Out of the 70 shop manual:

24nk5l0.jpg
 
Well it's not looking good, there were 3 kinds of valves. There is actually an old post about on here and found some other info on the net about it. The one I have is a valve for drums. The only way to use it for disc/drum brakes is with a rear hold off valve(valve shaped liked Texas). This is the way they did it in mopars until 71. After that they built in the hold off valve to the main valve. which gives it the different shape. Like the one in the pic that hemi71x posted.
 
67Dart273 said:
WHAT MODEL YEAR is your original car, and I assume it has drum brakes?


The valve pictured IS NOT a proportioning valve. It is quite simply a distribution block with the warning light switch. The switch consists of a simple piston which is normally centered, with the switch OFF. IF one "end" or the other loses pressure, the piston "shuttles" to one side, triggering the switch.

This thread:

http://www.forabodiesonly.com/mopar/showthread.php?t=134889


The photos below clearly show that at least some cars use SEPARATE prop. valves I found one drawing that seems to indicate that some cars used a 1 switch, 2 a metering valve, and 3 a prop valve in the same car.

These drawings are out of the 67 and 69 shop manuals:

sd0b3n.jpg


98aqlw.jpg


Out of the 70 shop manual:

24nk5l0.jpg
Click to expand...

I guess it's not technically a proportioning valve. So your right. But you could use it with a rear hold off valve(what one of your pics is pointing to and labled as a prop. valve), to make it work on a drum/disc car... I guess after 71 that piece was built into the main piece. Bummer for me!
 
New, adjustable, aftermarket valves from Summit and Jegs are not all that expensive.
 
Diesel0081 said:
Does anyone have a disc/drum proportioning valve for a good price?
Click to expand...

I have valves and lines, just like the picture that i posted.
Can furnish the correct length hard lines from the valve to the master cylinder, for either power brake, or manual brake applications.
The hard lines are shorter, or longer, depending upon application.
Jim V.
 
hemi71x said:
I have valves and lines, just like the picture that i posted.
Can furnish the correct length hard lines from the valve to the master cylinder, for either power brake, or manual brake applications.
The hard lines are shorter, or longer, depending upon application.
Jim V.
Click to expand...

How much we talking?
 
This is not a dumb question. I ran across the same issue when I converted my 73 Dart from drum to disk. When I began, the car had the disk brake master cylinder and a proportioning/metering valve that looked the same as the parts that I liberated from a 75 Valiant. Since it looked the same, I swapped the front and rear brakes on the 73 for BBP disk. Not only did it work, in several panic stops, the fronts locked first. Just as they should without ABS.

To respond to this question, I consulted the FSM and parts manual. The FSM stated that drum brake cars used a simple T with a switch. There are four connections to this T. 2 each from the master cylinder and the wheels. The combination distribution-metering-proportioning valve has five connections. 2 from the master cylinder, one to each front wheel and one to the rear. From this point on, both the FSM and parts book are confusing. No part number is given for the separate proportioning valve, but it is shown in diagrams.

Could the OP have a combination valve oh his Dart? IMO, yes. Would it be calibrated properly? Who knows. The parts manual confuses things by listing a different A-body Tee at the rear axle for disk and drum brakes. (3420 021 - drum brakes, 3549 947 - disk brakes) Both of the rear Tee s I have on the rear axles are 947s.
 
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