School me on master cylinders

Brakes, Steering & Suspension

  1. Northwest

    Northwest Well-Known Member

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    So I have a 71 with factory power disc / drum that I recently upgraded to Wilwood four-piston calipers up front.

    Works OK and all - but still use lots of pedal pressure and not getting much 'stop'. Wilwood tells me it should be fine - and I am going to get an adjustable prop valve - but I'm still using the factory master cylinder:

    images.jpg

    Which I believe has a 1 1/32 bore size.

    My thought is an upgrade is needed anyway since the factory one is old, heavy, and probably not giving me the best performance anymore.

    I am thinking about upgrading to something like this. with a slightly larger (1 1/8) bore, and obviously lighter weight:

    b-3360.jpg

    Of course there are tons of options - and I know more bore will increase required pedal pressure, but I have also upgraded to the Wilwoods - so is more volume or more pressure needed?

    Anyone school me on what master would be a good upgrade and why?
     
  2. Jeremiah

    Jeremiah Well-Known Member

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    I use a 1976 Plymouth Valiant manual disc brake master cylinder on my Charger with Wilwood Dynalite calipers on 11.75" rotors and it stops great.
     
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    • Northwest

      Northwest Well-Known Member

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      Jeremiah - I just read your other post on the strut rod thread.... Is that a 15/16 bore master cylinder you are referring to?
       
    • dvw

      dvw Well-Known Member

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      Master cylinder piston is to large. Go here and do the math. It will tell you all you need to know.
      Doug

      http://www.markwilliams.com/braketech.aspx
       
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      • Jeremiah

        Jeremiah Well-Known Member

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        I want to say it is around 1" but I will check...

        According to the book it is 1 1/32 bore on that master. I think a power brake application is 15/16".

        I also have 15/16" rear wheel cylinders which IMO helps the pedal feel with the 1 1/32" master cylinder. Too bad you are so far away you could drive both and decide for yourself. Also of note I run an adjustable proportioning valve on the rear brakes which also help fine tune things further.

        Looking through the rock auto catalog is confusing because they use a 1 1/32" master cylinder for every disk brake application from 71-76 power or not. From what I remember that is incorrect. Perhaps one of the others can help us here.
         
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        • Grabinov911

          Grabinov911 Well-Known Member

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          Jeremiah,

          Check with the folks at Mancini Racing. I am just about to do the Wilwood upgrade you are talking about, and used the Mancini Master Cylinder at their recommendation(I did the M/C first, will do brakes later). My car is non-power, but they can tell you which the right M/C is to use from their catalog - their parts look just like the part you picture in your post. Here's the thread I did on the installation - all the gory details!


          http://www.forbbodiesonly.com/mopar...e-Master-Cylinder-(with-a-Mancini-Racing-Kit)

          Greg
           
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          • 68 Sport Satellite

            68 Sport Satellite FBBO Gold Member FBBO Gold Member

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            Now that's something I never thought about. I also upgraded to Wilwood forged dynalite calipers with 11.75" Napa rotors and have been chasing pedal feel issues. I have stock rear drums on my '68 Satellite and never considered that with my 15/16" Raybestos Master Cylinder that I should look at my rear drum wheel cylinder size. Hmmmm.....

             
          • Northwest

            Northwest Well-Known Member

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            Well,

            I pulled the existing master which sure looks like 1 1/32 to me. It sure isn't 1 1/8 and it sure isn't 1.00.

            According to Mark Williams calculators - it looks to suggest that a 1.00 master is called for. Not sure how much difference a 32nd of an inch is going to make in the bid scheme of things...

            I do also have the 15/16 wheel cylinder in the rears already.

            Guess I need to do some calling around and see what else I can find out.

            IMG00039-20130214-1720.jpg
             
          • 67 coronet

            67 coronet Well-Known Member

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            master looks kinda nasty in your pics.when was the last time it was changed?i like to use the master off a 79 dodge pup with manual brakes for most of my convertions.price is much better then the aftermarket masters and still gives great stopping power.looks almost identical to aftermarket master in your pick above.
             
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            • Northwest

              Northwest Well-Known Member

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              There is some corrosion on the power booster that I think infected the master where they mate. Probably needs to be changed anyway... maybe's got 10 years on it? Seems like yesterday that I got it, but the mind goes you know...
               
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