Best Power disc brake conversion kit for 1968 Coronet Sedan

Brakes, Steering & Suspension

  1. Kip Page

    Kip Page Active Member

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    I have power front drums brakes and I want to convert to disc.... do I need the booster etc too?? what kits are the best...thx
     
  2. Mopar Hunter

    Mopar Hunter Well-Known Member

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  3. BIGSHCLUNK

    BIGSHCLUNK FBBO Gold Member FBBO Gold Member

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    I will say, wheels are a factor in planning a brake swap. I don't run a booster
     
  4. Sixpactogo

    Sixpactogo Well-Known Member

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    Your drum brake booster won't provide enough boost for front discs. You will need to replace it with a dual ballast unit.
     
  5. Joe66satellite

    Joe66satellite Well-Known Member

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    Even with an adjustable proportioning valve?
     
  6. Billccm

    Billccm FBBO Gold Member FBBO Gold Member

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    email Dr Diff
    he will get you a plug and play kit
     
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    • Sixpactogo

      Sixpactogo Well-Known Member

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      Yes. You will end up with a hard pedal and not enough boost to lock the wheels. Front or back. If you don't upgrade to the dual ballast booster, you would be way better off with no booster at all. Ask me how I know.
       
    • Joe66satellite

      Joe66satellite Well-Known Member

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      So I guess I pissed my money away on an adjustable proportioning valve then, haven't installed it yet
       
    • Sixpactogo

      Sixpactogo Well-Known Member

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      Not necessarily. You will need a proportioning valve with front disc and rear drums no matter what. For the most part, they're job to delay the pressure to the rear brakes so they don't lock up first sending you into an end for end spin when you want to stop. The adjustable one just gives you more input.
       
    • BIGSHCLUNK

      BIGSHCLUNK FBBO Gold Member FBBO Gold Member

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      I run an adjustable PP valve. You can dial things in very nicely
       
    • SoCal440GTX

      SoCal440GTX Well-Known Member

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      I'll bite...how do you know?
       
    • Sixpactogo

      Sixpactogo Well-Known Member

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      Some lessons are costly......My 68 Charger had power drum brakes originally that worked fine. When I converted to front discs, I couldn't stop the car and the pedal was hard. I thought my booster was bad so I sent it to Booster Dewey for rebuild. Reinstalled it and had the same issues. Then I replaced the master cylinder thinking that was the problem. It wasn't. I finally called Cass at Dr Diff and was told the same message I gave in post 7. I needed the dual ballast booster to provide enough boost for the front discs. If I had asked the question like Kip Page did before spending a few hundred dollars and a couple weeks of trial and error wondering what the hell was wrong, I would have saved myself a bunch of grief and money.
       
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      • 1 Wild R/T

        1 Wild R/T Well-Known Member

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        Never heard of a dual ballast brake booster....

        I’ve heard of a dual ballast used in the ignition

        And I’ve heard of a dual diaphragm brake booster

        But no dual ballast brake boosters...
         
      • Sixpactogo

        Sixpactogo Well-Known Member

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        I guess the technical term is diaphragm. Either way, a single (diaphragm or ballast) will not provide enough Boost or ballast for front disc brakes. Clear as mud?
         
      • 1 Wild R/T

        1 Wild R/T Well-Known Member

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        Well great, I guess I have to replace the original single diaphragm brake booster on my Challenger... Oh, wait, the brakes have worked great ever since 1970...
        Maybe the fact that 80+ % of the disc brake cars having single diaphragm boosters should be considered here...

        The fact allot of guys run discs with no booster at all means something...

        Perhaps pedal pressure, mechanical advantage, M/C bore sizing and the booster all are a balanced package... And if you get it wrong then either you get a hard pedal or a very touchy pedal..
         
      • Sixpactogo

        Sixpactogo Well-Known Member

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        I'm not here to argue the point one way or another. Just trying to save some people some grief. All I have to go on is my own experiences and word of mouth from others that have been down the same road. I had a 70 Challenger with disc brakes too but it was manual not power so I have no input as to whether a single diaphragm booster is enough. If it works good for you, that's all that counts. This is a B body site and from what I've seen and been exposed to on the 68-70 B body cars with power disc brakes, (which this particular thread pertains to) The factory provided the dual diaphragm booster. They would not have done that if they felt it was not needed.
        Probably closer to 100% of the newer cars have single diaphragm booster because they are manufactured to work with newer systems. You are correct in saying Master cylinder bore comes into play and you need a balanced package.
         
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