PROPORTIONING VALVE PROBLEM

[Larry Chilese]

i Have a 1970 Dodge Charger R/T all drum brakes. I replaced all components from master cylinder down to brakes cylinders and shoes.
New proportioning valve seems to have stuck leaving the front brakes getting fluid and the rear getting nothing-I used a vacuum bleeder too bleed.
I can't find a Mopar tool like the Chevy tools the restrict the valve from moving while bleeding. So I am stumped.
I tried boosting the system with an air blast but could not get things loosened up. Any suggestions: thanks much in advance.

 

[furyus]

Check with Dr Diff. He might have the item you need. Very good to deal with.

 

[hunt2elk]

The factory service manual tells how to reset the valve. Luckily, I have never had that happen to me and had to do it.

 

[pnora]

i Have a 1970 Dodge Charger R/T all drum brakes. I replaced all components from master cylinder down to brakes cylinders and shoes.
New proportioning valve seems to have stuck leaving the front brakes getting fluid and the rear getting nothing-I used a vacuum bleeder too bleed.
I can't find a Mopar tool like the Chevy tools the restrict the valve from moving while bleeding. So I am stumped.
I tried boosting the system with an air blast but could not get things loosened up. Any suggestions: thanks much in advance.

Did you bench bleed the master cylinder first?

 

[Dragon Slayer]

Drum drum did not use a proportioning valve. Just master cylinder and distribution block with warning light. Why do you have a proportioning valve?

 

[ruffcut]

A picture of the part in question may help to get a resolution to your problem. JMO ruffcut

 

[Larry Chilese]

Where can I find Dr. Diff?
The car came with one installed. Car is pretty original in condition-all original brake lines and hoses wheel Cyl. as well. Master Cyl was replaced.
Master Cyl has [2] ports F and R- [1] line to rear and [2] to the front drums. Where could I find a junction block w/ [5] posts of the proper size for fittings I wonder.
I've thought of just removing the valve and letting it just act like a junction block, haven't got to that point yet.

 

[moparedtn]

 

[Kern Dog]

4 wheel Drum cars did NOT have a proportioning valve.
They did have a junction block where the lines from the master cylinder enter and 3 lines that exit and go to the rear ( One line ) and the front (Two lines, one left, one right )
The junction block is also called a distribution block. It has no proportioning to it. The front system gets the same pressure as the rear. The factory fitted the cars with bigger front wheel cylinders (than the rear) along with sometimes making the front shoes wider.

This is a standard 4 wheel drum distribution block. Note it's shape.

This is a front disc, rear drum proportioning valve.

It is longer and the bottom left kicks out a bit.

 

[Larry Chilese]

yes I did bench bleed my proportioning valve prior to installing it.
Where can I find a correct junction block, would solve all my problems, all I can find is the proportioning valve.

 

[Larry Chilese]

I see the photos of the junction block-appreciate it much-does it have a threaded hole for the brake light switch?
My car has the wire from dash to this switch so I've assumed it goes into that junction block-but not sure how it triggers the switch

 

[Larry Chilese]

Sorry I meant I did bench Bleed the Master Cylinder prior to install.

 

[Rockland71GTX]

Larry, You have a distribution block with a brake warning switch with all drum brakes. The warning light is on the dash, it is not the brake light switch.
Downloada free service manual from : Service Manuals – MyMopar

 

[Curiousyellow71]

I would guess you master cylinder didn't bleed or both front brake hose's have collapsed and need replacing.

 

[Larry Chilese]

I did bench bleed the master cylinder properly and the hoses are new and not collapsed as I am getting fluid the front.
I did take heart to Kern Dogs posts and found a distribution block from In-Line. Going to install that and that should solve my problems.
Thanks again for increasing my learning curve, much appreciated, can't wait to get it on the car!
Larry C

 

[Curiousyellow71]

Sorry, I missed a few of your posts. A new hose can be bad as well. Might want see if you have fluid in the line at the front side of the rear brake hose or maybe at distribution block where it sends it into the rear. Regardless sounds like you are on your way to solving it. Not many chargers around be great to see another one in Nebraska driving around.

 

[Sixpactogo]

I believe you already have the correct distribution block since you still have drum brakes. You can take it apart and re-center that piston assembly. That piston will move to one side or the other and create a ground path to the switch to turn on the light on the dash warning you of a problem. When you were bleeding the brakes, it got displaced causing no fluid to the rear. I had that happen to me once also. I had to manually push that piston back to center. As was mentioned, there is a tool to swap into the switch to prevent that from happening but too late for you now. You will have to center that piston. I have seen directions on line to fix it.

 

[Kern Dog]

This is also a distribution block that I disassembled.

 

[Kern Dog]

This is a proportioning valve from a 1973-1976 A body.

The distinct difference is that kick out at the lower left.

 

[dadsbee]

The OP posting a picture, of what they currently have, in all of these "why" threads would help immensely !