4 piston to single piston swap. 72 Demon

Brakes for your Classic Mopar

  1. Woodie

    Woodie Take-off EH!

    Messages:
    458
    Likes Received:
    136
    Joined:
    Feb 10, 2012
    Location:
    Ontario
    Local Time:
    4:04 AM
    I Planning on swaping out the factory 4 piston set- up currently on the Demon in favor of a single piston set up I took off of a 73 Dart sport. Reason for this is I have SBP on the front and LBP aftermarket axles on the rear. Are the front spindles the same? Also curious if I use the same factory upper control arms as well. Will the brake proportioning still be the same?

    Thanks.
     
    • Like Like x 1
    • hemi71x

      hemi71x FABO Gold Member FABO Gold Member

      Messages:
      5,408
      Likes Received:
      1940
      Joined:
      Dec 22, 2009
      Location:
      Rancho Cordova, CA
      Local Time:
      2:04 AM
      No, spindles are not the same.
      Two totally different brake designs.

      You will need to change over your upper control arms to 73-76 large ball joint ones, and change your lower ball joints over to 73-76 ones.
       
      Last edited: Dec 11, 2016
      • Like Like x 1
      • Woodie

        Woodie Take-off EH!

        Messages:
        458
        Likes Received:
        136
        Joined:
        Feb 10, 2012
        Location:
        Ontario
        Local Time:
        4:04 AM
        Thanks for the info. Need to source a set of upper control arms. I have everything else.
         
        • Like Like x 1
        • hemi71x

          hemi71x FABO Gold Member FABO Gold Member

          Messages:
          5,408
          Likes Received:
          1940
          Joined:
          Dec 22, 2009
          Location:
          Rancho Cordova, CA
          Local Time:
          2:04 AM
          Search hemi71x in the for sale section of this forum.
          I have a pair of UCA's for sale.
           
          • Like Like x 1
          • Woodie

            Woodie Take-off EH!

            Messages:
            458
            Likes Received:
            136
            Joined:
            Feb 10, 2012
            Location:
            Ontario
            Local Time:
            4:04 AM
            Nice.
             
            • Like Like x 1
            • RedFish

              RedFish Well-Known Member

              Messages:
              24,030
              Likes Received:
              2696
              Joined:
              Sep 5, 2007
              Local Time:
              4:04 AM
              There are adapter bushings for the spindle holes that let one use the smaller ball joint and matching upper arm in the larger spindle hole. I haven't used these bushings. I'm not recommending them. FYI only.
               
              • Like Like x 1
              • Woodie

                Woodie Take-off EH!

                Messages:
                458
                Likes Received:
                136
                Joined:
                Feb 10, 2012
                Location:
                Ontario
                Local Time:
                4:04 AM
                Thanks for the input Redfish. Thinking of going aftermarket "Tubular".
                 
                • Like Like x 1
                • Jimacuda

                  Jimacuda Well-Known Member

                  Messages:
                  1,699
                  Likes Received:
                  541
                  Joined:
                  Nov 10, 2006
                  Location:
                  Phoenix AZ
                  Local Time:
                  2:04 AM
                  ball joint adapter is the way I'd go if the small ball joints and uca bushings are newer. DrDiff carries them.
                  No getting around replacing the lower.
                  73-76 A body lower ball joint, same piece disc or drum.
                   
                  • Like Like x 1
                  • Woodie

                    Woodie Take-off EH!

                    Messages:
                    458
                    Likes Received:
                    136
                    Joined:
                    Feb 10, 2012
                    Location:
                    Ontario
                    Local Time:
                    4:04 AM
                    Thanks Jimacuda.
                     
                    • Like Like x 1
                    • FredS

                      FredS Well-Known Member

                      Messages:
                      876
                      Likes Received:
                      66
                      Joined:
                      Feb 13, 2013
                      Location:
                      Arizona
                      Local Time:
                      2:04 AM
                      why not just use Mustang rotors and keep everything you currently have
                       
                      • Like Like x 1
                      • Woodie

                        Woodie Take-off EH!

                        Messages:
                        458
                        Likes Received:
                        136
                        Joined:
                        Feb 10, 2012
                        Location:
                        Ontario
                        Local Time:
                        4:04 AM
                        Just read that post.. Good read too. :)
                         
                        • Like Like x 1
                        • AJ/FormS

                          AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

                          Messages:
                          18,018
                          Likes Received:
                          6317
                          Joined:
                          Jan 19, 2014
                          Location:
                          South-Central Manitoba,Canada, 900ftelevation
                          Local Time:
                          4:04 AM
                          Sooooooooooo
                          What's wrong with different bps front to rear? I've been doing that for decades.
                          You know those 4-piston calipers are fabulous for a streeter. No sliders to wear out or pins to jam up, and pad replacements take mere minutes. Or hey, if one pistons freezes up in winter, due to moisture, there are still 3 others to get the job done,lol.
                          I really like my KHers. And I'm OK with 14x7s up front and 15x10s out back.
                          As to proportioning, that depends more on what your rear rubber can handle.My P-valve is gutted, and the rear could handle even more pressure.
                          Seems like a lotta work, for what I would call a minor gain.
                          But if you are wanting to run 4 same-size, interchangeable, wheel assemblies; that I can understand.
                           
                        • Woodie

                          Woodie Take-off EH!

                          Messages:
                          458
                          Likes Received:
                          136
                          Joined:
                          Feb 10, 2012
                          Location:
                          Ontario
                          Local Time:
                          4:04 AM
                          ..I agree with the with your thoughts.. I have Centerlines front and rear. I want to run a set of Cop wheels with 15x6 up front an 15x10s on the rear for a Nasty look. I have a complete set of 73 front discs, spindles minus the Upper Control arms. (I gave them to a friend in need a while back) just seeing what my options are. Also i feel its time to rebuild the entire front end, pull it apart and make it new again.
                           
                        • AJ/FormS

                          AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

                          Messages:
                          18,018
                          Likes Received:
                          6317
                          Joined:
                          Jan 19, 2014
                          Location:
                          South-Central Manitoba,Canada, 900ftelevation
                          Local Time:
                          4:04 AM
                          I forgot to mention;
                          I was so busy finding fault with the 73Up stuff, that it slipped my aging mind. The KH stuff has been trouble-free for me to the tune of 17 years and 125,000 plus miles. That's Zero maintenance required.And no, I have never had a moisture issue with DOT5.Nor the so-called compressibility.I do have the Teflon-lined front hoses. Awesome street brakes with the 10 x 2.5s and 295s out back doing a good portion of the work!I have never had a car that braked; better, harder,or in a shorter distance.And I think I may have only ever been in one other comparably stopping street car,since 1969. I think all cars should have bigger tires and harder working brakes, out back. I mean think about what that P-valve is doing. It is preventing the rear from skidding the tires and initiating a spin.Wouldn't more rubber back there have been a better idea? I thought so, and that's partly why I worked so hard to get the bigger boots back there. Well that and spinning out on every turn-under-power, was getting old........lol
                           
                          • Like Like x 1
                          1. This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
                            By continuing to use this site, you are consenting to our use of cookies.