brake bleeding, no front

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Hersbird

Hersbird

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So I put some 73 front discs on my 68. I have a new master cylinder (73) which I bench bled. I reused my original front lines, but I used the prop valve off the 73. All new front calipers. So when I push the peddle I can get good fluid out the back and seem to have good rear brakes but cant get anything out the front. I read about the re centering the valve and tried to open the rear bleeder and push and hold the peddle all the way in but can get no click. I was just slowly pushing the pedal not stomping on it. The 73 prop valve was old and on a car that had sat for a long time I wonder if it's froze up. The other thing that seems weird is with the cover off the MC when you push the pedal a stream shoot up out of the small reservoir (which is the rear brakes right?) the big reservoir just sits there still. Is there something on the master cylinder that needs to be reset? Can I use my old 68 prop valve instead? it was all drum.

I did move the car around in the driveway which makes me happy as I rebuilt the motor and tranny at the same time and that is all looking great. I got rear brakes and the brake warning light was coming on when I pushed the peddle in. I want to drive this bad boy and think front brakes would be a nice complement to the increased power LOL!

edit. I see this is called combination valve not proportioning valve and the 68 one wont work. What if I used the 68 one but added a rear adjustable proportioning valve? Or does anybody have a low priced source for a new 73 valve?
 
I'm starting to wonder if the line from the MC to the block for the front brakes is clogged. Now the light stays off and the rear brakes work great the pedal is firm but no front brakes and that geyser thing on the small reservoir only. Tomorrow I'm going to take that line off and see if there is flow to the block.
Where is the ebay one? I see some universal looking GM ones for that price but question if all the fittings are the right size, right orientation, right proportioning bias, etc.
 
When I converted my 69 from drum to disc front I used the original drum proportioning valve and added an adjustable valve to the back brakes.

It all works like it should ,I did use a new plastic resivoir type master cylinder off an 1980's aspen or volare.
 
Have you tried opening the caliper bleeders and let it gravity bleed?Sounds like air in the system or as you said..clogged.
 
Do you have a nice hard pedal? First thing I'd do is crack the line going into and out of the dist. block and see "where" you are losing flow.
 
AS already said. If line from MC to valve checks OK, you can loosen a front line fitting to confirm no flow out of valve. Then it is no doubt where problem is...
Not sure about the rod length. That may be an issue in getting correct braking,and should be checked when switching MC, but I think you would still see flow with a line open.
I have seen a few posts that say some of the new valves not working right. Don't know about current production.
Here's a seal kit if you want to rebuild the used valve.
https://www.musclecarresearch.com/mopar-seal-kit-2
they also have pics of dissambled valve on same site.
You might get away with cleaning it up. The bottom end collects a lot of gunk. If no internal damage, its just a matter of dissasembly, clean (mostly just flush with clean fluid) and reassemble. I did mine before I saw the seal kit, with parts from 2 valves to make one.
 
Well it was the line between the master cylinder and the proportioning valve. Sweet, because besides being hard to undo down at the block, I had the old one and now its working. I need to go through the whole bleeding process again but I am getting good flow out of all the wheel cylinders now.
 
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