Aftermarket MC brake issues

Discussion in 'Early A-Body Discussions' started by mycuda, Nov 7, 2018.

  1. AJ/FormS

    AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

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    I think that they gave you a bs line, cuz that is part of the safety system. If the rear brakes rupture a hose, your pedal will fall to near the floor driving the rear-most piston mechanically into the front-most piston. Then the two of them will continue to slide down the bore until the front brakes stop the car. This might pretty much use up all the piston travel. The frontmost piston has a stopper on it that prevents the frontmost seal from bottoming out. So on a new/rebuilt unit, bottoming out the pistons is no biggie........ plus that is how we bench bleed them.
    Now if this happens to you on a MC with many years of service on it, it could be that the end of the bore has rust in it; (not likely cuz it's uphill and water don't collect up there, but let's say it did), then the piston seal could run over the rust and not appreciate that very much. But that is a reeeeeeeeeally long stretch.
    MCs are really simple devices, and if the fluid is kept uncontaminated, should last for decades.
     
  2. mbaird

    mbaird mbaird FABO Gold Member

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    I chased this very problem for weeks . I finally asked my buddy Kevin (freakin mopar savant!) to look at them. Took him all of 30 seconds ! You have your calipers on wrong...

    RATTINFRATTINMOTHERFREAKIN...... lol
     
  3. BillGrissom

    BillGrissom Well-Known Member

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    Is there anything blocking the pedal from allowing the MC to push the piston all the way out to its stop? If so, the piston may not be exposing the refill port. A common issue is that people think the pedal is supposed to bottom out on the lamp switch. No, the switch should just sense the pedal motion, not affect it.
     
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    • mycuda

      mycuda FABO Gold Member FABO Gold Member

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      No.
      putting different MC on tomorrow.
      Hopefully prove myself right...
      Will respond.
       
    • Lucas

      Lucas Member

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      I have run into lots of issues with the built in parking brake on the rear calipers.
      There is a very small window of operation and if not set correctly can cause a long pedal on apply.
      Lots of basic disc brake swaps come with those calipers for the rear and so many times have very poor instructions.
       
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      • mycuda

        mycuda FABO Gold Member FABO Gold Member

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        Bingo! Lucas wins the prize!

        All I can say is when you install rear disc brakes, dont put wheels on. Just tighten rotors tight with regular lugnuts.
        Now you adjust parking brake. In my case custom cable set up. Until pads just start to hit rotors with ebrake off. But can still move rotors by hand in neutral with a little force.
        NOW BLEED BRAKES!!!!!!!! Incredible how easy it really is. Now I have a pedal.....:lol:

        Thanks,Dave
         
      • mbaird

        mbaird mbaird FABO Gold Member

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        Maybe that should be in the instructions ?
         
      • mycuda

        mycuda FABO Gold Member FABO Gold Member

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        Yep.
        There was none.
         
      • Lucas

        Lucas Member

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        Glad I could help.
        I know how frustrating the lack of good instructions can be.
        I recently had the pleasure of installing Baer brakes all the way around on a RR and have to say that they were not only the best instructions but also actually performed awesome.
        The biggest part that sucks is the price but ya pay for what you get.

        Thanks.
         
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