4 wheel disc on 74 Duster - Prop valve?

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zig

zig

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I am working on getting my car driving after 4 years... Down to the last few items.

The car had front disc and rear drums stock. I upgraded to 11 3/4 up front using Cordoba rotors and mount. I bought a kit off of ebay for the rear. It is all hooked up. I finally started the car up today, had it up on jack stands and shifted into gear. The rear keeps going unless I mash the brakes all the way to the floor. And even then, doesn't want to stop. I think I need to adjust the rear calipers a bit. There is some adjustment. But I noticed my prop valve is leaking... So another thing to replace.

Any recommendations? Should I upgrade to something else? I did a little research using the search function. But mostly lots of opinions. I am looking for someone else running 4 wheel disc brakes for what they are using.

Any help is appreciated. The old car is finally ready to drive. Excited and nervous at the same time...
 
Don' know what to tell ya. Sounds like a master/ bleeding / plugged problem, not so much a "parts" problem

I (was until paint shop jail) run 73 /4 front Duster brakes, and rear Linc Versailles disk, with NO prop valve, only the original 67 warning switch. I even run the old original drum master---just punctured the residual valves. Stops perfect
 
Try calling the Ram Man. He is an expert on brakes and can walk you though your system and let you know what you need to get it to work. He also sells components. I would give him a call.


7200 Winters St
Fort Worth, TX 76120
Telephone: 817.691.5996

http://www.theramman.com/
 
I run a wilwood adjustable valve plumbed after the stock proportioning valve ( so the warning light still works.

I'm running stock manual disc / drum master cyl with an exploder disc rear end. Took about 30 min to "tune" the rear with the adjustable valve ( and I was taking my time )

You can remove the stock prop valve IF you plumb the front together then run the adjustable valve from the master rear line AND you don't care about the stock warning light.
 
Unless something is wrong, the caliper pistons should move outward in lock-step with the pedal. It is a simple volume-volume relationship. Have someone watch the rear calipers as you push the pedal. If it isn't leaking somewhere, the only other place the fluid volume can go is to move the "imbalance switch" piston, but that should be against the rock-solid front hydraulics. The calipers shouldn't retract much when you release the pedal, since all that retracts them is relaxation of the square O-ring seals.

Above assumes you have only fluid in the lines and your rubber hoses aren't bulging. Best guess is you have air in the system. Are the bleeds on the rear calipers at the very top?
 
Player1up
Do you have pic of your set up? Doing same thing to mine. Thanks!
 
Sorry CudaDust, zig is gone. We prefer it when people who ask questions give "the rest of the story".
 
Bill,
Sorry to hear about Zig.
Think I have all my questions answered in a tread I started but wanted to see what Player1up had done and some Pictures.
Thanks!
 
The pics didn't really come out. It's like there's no way to get a phone or camera in there to get a good picture.
I'll try to describe it as best I can, but all I did was unbolt the rear brake line from the stock proportioning valve, screw it into the adjustable valve and ran a new loop of brake line between the proportioning and the adjustable valve with enough line to loop up where I can adjust it from the engine bay....
Pain in the but to bleed, but it works...
 

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Player1up,
Thanks for the Picture looks like a good spot to me. Below master so should gravity feed to bleed but bet it takes some time and reachable so you can get to it to adjust. Also away from heat of engine.
Thanks for taking the time to get a picture for me!!!
 
player1up said:
The pics didn't really come out. It's like there's no way to get a phone or camera in there to get a good picture.
I'll try to describe it as best I can, but all I did was unbolt the rear brake line from the stock proportioning valve, screw it into the adjustable valve and ran a new loop of brake line between the proportioning and the adjustable valve with enough line to loop up where I can adjust it from the engine bay....
Pain in the but to bleed, but it works...
Click to expand...

the same set up I used on my 73 dart sport with the 8.8 rearend swap. once it's bled out, it works really well. I did make some new lines from master cyl to the wildwood valve. I also had to make some ext. lines to hook to the oem lines. I also went to the hardware store and got a couple chrome 1/2" spacers for the prop valve mounting. Spaces it out from the inner fender a little.
I also back bled my rear brake system, it seemed to help, I work alone a lot.
 
Different body, but this bleeds fine.
IMG_0537.jpg
 
Thanks for the time to answer to my thread and pictures!!! Thanks for the tip on the back bled on the rear I work alone also.
 
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