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Sudhanshu
Inspiring
November 11, 2025
Question?

Front Brake Master Cylinder – fitment & spongy lever after upgrade

  • November 11, 2025
  • 40 replies
  • 236 views

Replacing stock master cylinder with an aftermarket unit. Lever feels a bit spongy even after a quick bleed. Looking for best-practice on piston size, banjo/crush washers, ABS compatibility, and bleed order.

    40 replies

    S
    SudhanshuAuthor
    Inspiring
    November 11, 2025

    Full bleed order matters on ABS bikes: MC → ABS module → calipers. Vacuum + reverse bleed helps.

      S
      SudhanshuAuthor
      Inspiring
      November 11, 2025

      If lever firms up then fades, air is trapped in the ABS modulator—cycle it.

        S
        SudhanshuAuthor
        Inspiring
        November 11, 2025

        Check the tiny return port in the reservoir isn’t clogged.

          S
          SudhanshuAuthor
          Inspiring
          November 11, 2025

          Quick data point: swapping in fresh crush washers and re-torquing the banjo stopped the slow lever creep for me.

          sudhanshu_sabharwal
          sudhanshu_sabharwal
          Sudhanshu Sabharwal
          December 10, 2025

          Testing L2 single page 

            sudhanshu_sabharwal
            sudhanshu_sabharwal
            Sudhanshu Sabharwal
            November 20, 2025

            Reverse-bleed from caliper with a syringe to push air up

            sudhanshu_sabharwal
            sudhanshu_sabharwal
            Sudhanshu Sabharwal
            December 11, 2025

            your final bleed order/torques; it helps the next service.

              sudhanshu_sabharwal
              sudhanshu_sabharwal
              Sudhanshu Sabharwal
              November 20, 2025

              Test level 1

              sudhanshu_sabharwal
              sudhanshu_sabharwal
              Sudhanshu Sabharwal
              December 11, 2025

              trial

                sudhanshu_sabharwal
                sudhanshu_sabharwal
                Sudhanshu Sabharwal
                November 20, 2025

                Test L1

                sudhanshu_sabharwal
                sudhanshu_sabharwal
                Sudhanshu Sabharwal
                December 11, 2025

                Check

                  sudhanshu_sabharwal
                  sudhanshu_sabharwal
                  Sudhanshu Sabharwal
                  December 11, 2025

                  3rd level

                    sudhanshu_sabharwal
                    sudhanshu_sabharwal
                    Sudhanshu Sabharwal
                    November 20, 2025

                    Test L1 again

                    sudhanshu_sabharwal
                    sudhanshu_sabharwal
                    Sudhanshu Sabharwal
                    December 10, 2025

                    Test L1 pagination control

                    sudhanshu_sabharwal
                    sudhanshu_sabharwal
                    Sudhanshu Sabharwal
                    January 9, 2026

                    L2

                      sudhanshu_sabharwal
                      sudhanshu_sabharwal
                      Sudhanshu Sabharwal
                      January 9, 2026

                      @sudhanshu_sabharwal L3

                        sudhanshu_sabharwal
                        sudhanshu_sabharwal
                        Sudhanshu Sabharwal
                        December 10, 2025

                        Test L1 pagination control

                        sudhanshu_sabharwal
                        sudhanshu_sabharwal
                        Sudhanshu Sabharwal
                        December 10, 2025

                        Test L1 pagination in control

                        sudhanshu_sabharwal
                        sudhanshu_sabharwal
                        Sudhanshu Sabharwal
                        December 10, 2025

                        Test L1 pagination in control

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