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1968 Mustang Fastback
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Discussion Starter · #1 ·
I have a 68 with a 289 that was previously an automatic, which I recently converted to a 5 speed. While doing the conversion, I had to remove the brake master cylinder and the power brake booster to get the hydraulic clutch in. The car has factory disc brakes. I also had Midlife rebuild my wiring harness.

When I put it all back together, I found that the brake warning light was illuminated on the dash. I figured this was because I had to bleed the system. When I tried to bleed it, I couldn’t get any brake fluid to come out of the rear bleed valves. I tried stepping on the pedal, and using a vacuum pump. The front brakes were fine, and I easily bled them. So, I have no back brakes. I’m assuming this is the proportioning valve, or the distribution block.

Can I take the valve and the block apart and just clean them? Or should I just replace? Or should I be looking at something else?

I did check all the brake lines and could not find any pinches, kinks, or holes, they seem to be fine.
 

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1967 GT500
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Your distribution block is not centered which is causing your dash brake light to go on. I am not sure if this alone would stop all fluid to the rear. You will need to bleed the fronts again to reset the valve. I assume you have drums all around?
 

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1968 Mustang Fastback
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Discussion Starter · #3 ·
Your distribution block is not centered which is causing your dash brake light to go on. I am not sure if this alone would stop all fluid to the rear. You will need to bleed the fronts again to reset the valve. I assume you have drums all around?
Discs in front, drums in back.
 

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Are you using a Ford factory distribution block or a "GM Knock Off"?
 

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How old are the brake hoses?
 

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Did you use a "centering tool" (replaces the brake Lt switch indicator) when you bled the brakes?
 
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1968 Mustang Fastback
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Discussion Starter · #9 ·
Did you use a "centering tool" (replaces the brake Lt switch indicator) when you bled the brakes?
I did not. does it plug into the electrical connector on top of the block?
 

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1968 Mustang Fastback
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Discussion Starter · #10 ·
After pushing on the brakes a bunch and getting my camera down in there, It appears my proportioning valve is leaking...
789859
 

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Aside from the leaking proportioning valve take a good look at the rubber line in the back that connects from the body to the axle. It could be blocked internally and keeping the fluid from getting to the rear brakes.
 

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I did not. does it plug into the electrical connector on top of the block?
yes, it's a needed it item. Also, unless you know otherwise, all of the rubber brake hoses are suspect. The deteriorate internal and can plug the lines, not to mention create a "blow out" situation. Therefore, they should be replaced.
 

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The complete valve needs rebuilt. The piston in the Proportioning valve is stuck, which is not letting the fluid through. You can bet the Distribution block is full of trash as well. Do rebuilt the Proportioning valve and not the block as the new fluid will flush out the trash in to the Proportioning valve---Then you start all over.

Scott has rebuild kits at Muscle Car research. Getting it apart will be the challenge as it will be stuck.
I keep his kits is stock as well.
 

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1968 Mustang Fastback
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Discussion Starter · #16 ·
Good advice! I'll go ahead and replace all three rubber lines, and either rebuild or replace both the proportioning valve and the block.

Anyone know where I can find the "centering tool"? All the ones I see online are for Chevy applications.
 

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Discussion Starter · #18 ·

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I think that dash light has been on since '82. Maybe I should be concerned. (actually a lot of that time it has been unplugged, probably not a recommended solution).
 

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Discussion Starter · #20 ·
I think that dash light has been on since '82. Maybe I should be concerned. (actually a lot of that time it has been unplugged, probably not a recommended solution).
That's funny! mine was unplugged when I got the car. Strangely, the brakes feel like they did then, so who knows how long this thing has been without rear brakes.
 
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