Rear Master Cylinder - checking it after rebuild

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  • Gregory
    Forum Sage
    Past Site Supporter
    • Sep 2012
    • 2064
    • Southlake - DFW - North Texas

    #1

    Rear Master Cylinder - checking it after rebuild

    GS1000 rear master cylinder and caliper rebuild.

    Just got things put back together using the tutorial from Basscliffs site. I believe the line is clogged because I cant even get air bubbles it through it by blowing on the line.

    Here is the question:

    Is it possible to check whether the master cylinder is working without having the line or caliper attached?

    I filled the reservoir and pumped the piston and no fluid comes out the end where the banjo bolt goes. Should there be pretty good pressure?
    82 gs1100e FAUX Skunk
    80 gs1000s
  • slyone

    #2
    I just did my front M/C, calipers & hoses and much to my surprise, I found 1 of the old hoses completely plugged up at one end I picked it open, sprayed cleaner thru and blew out but had decided to renew just due to age. I plan on going thru the rear setup prolly this winter or next spring.

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    • Nessism
      Forum LongTimer
      GSResource Superstar
      Past Site Supporter
      Super Site Supporter
      • Mar 2006
      • 35793
      • Torrance, CA

      #3
      Originally posted by slyone
      I just did my front M/C, calipers & hoses and much to my surprise, I found 1 of the old hoses completely plugged up at one end I picked it open, sprayed cleaner thru and blew out but had decided to renew just due to age. I plan on going thru the rear setup prolly this winter or next spring.
      Wow man! Darwin award winner in training.

      Ditch the crappy, full of sludge, original lines and get new.

      As for the master that won't pump, make sure the small return port is open and prime it (fill the pumping cylinder with fluid). Sucking a vacuum on the caliper nipple usually does it. You can do it with the caliper off the bike too.
      Ed

      To measure is to know.

      Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

      Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

      Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

      KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

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      • Gregory
        Forum Sage
        Past Site Supporter
        • Sep 2012
        • 2064
        • Southlake - DFW - North Texas

        #4
        Originally posted by Nessism
        Wow man! Darwin award winner in training.

        Ditch the crappy, full of sludge, original lines and get new.

        As for the master that won't pump, make sure the small return port is open and prime it (fill the pumping cylinder with fluid). Sucking a vacuum on the caliper nipple usually does it. You can do it with the caliper off the bike too.

        Thanks Ed. I actually went back out and pumped on it some more and was able to feel some air pressure so I think it may be ok. As far as the line I haven't had any luck cleaning out either rear line I have. It is way too difficult to get a wire in the banjo bolt hole.

        That being said, anyone know what diameter line will work. I don't really want to put any money in this machine but saw this 33" long line on ebay for cheap.

        82 gs1100e FAUX Skunk
        80 gs1000s

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        • Gregory
          Forum Sage
          Past Site Supporter
          • Sep 2012
          • 2064
          • Southlake - DFW - North Texas

          #5
          BUMP... or should I start a new thread?

          That being said, anyone know what diameter line will work. I don't really want to put any money in this machine but saw this 33" long line on ebay for cheap.

          http://www.ebay.com/itm/85cm-33-034-...p2054897.l4275
          82 gs1100e FAUX Skunk
          80 gs1000s

          Comment

          • Nessism
            Forum LongTimer
            GSResource Superstar
            Past Site Supporter
            Super Site Supporter
            • Mar 2006
            • 35793
            • Torrance, CA

            #6
            Hi Greg,

            Here is a thread on making brake lines...http://www.thegsresources.com/_forum...d.php?t=114521

            From that thread you should be able to figure out what you need. As for length, I suggest you measure your old line and go from there.
            Ed

            To measure is to know.

            Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

            Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

            Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

            KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

            Comment

            • Gregory
              Forum Sage
              Past Site Supporter
              • Sep 2012
              • 2064
              • Southlake - DFW - North Texas

              #7
              Originally posted by Nessism
              Hi Greg,

              Here is a thread on making brake lines...http://www.thegsresources.com/_forum...d.php?t=114521

              From that thread you should be able to figure out what you need. As for length, I suggest you measure your old line and go from there.
              Thanks Much apprecitated
              82 gs1100e FAUX Skunk
              80 gs1000s

              Comment

              • Gregory
                Forum Sage
                Past Site Supporter
                • Sep 2012
                • 2064
                • Southlake - DFW - North Texas

                #8
                Originally posted by Nessism
                Hi Greg,

                Here is a thread on making brake lines...http://www.thegsresources.com/_forum...d.php?t=114521

                From that thread you should be able to figure out what you need. As for length, I suggest you measure your old line and go from there.
                Sorry if I am being dim.... but 10mm banjo bolts?

                I don't want to make them myself, but want to research various hoses. Yes I know the length, and I know it says 3/78 1/8 HR but are the banjo bolts 10mm standard?

                I am back to this bargain http://www.ebay.com/itm/85cm-33-034-...p2054897.l4275

                A guy locally can make me one for $15 out of black rubber, and that is what I may do, but for the bike I am keeping as a daily driver, this looks WAY more affordable than anything else I have run across...and they look braided.
                Last edited by Gregory; 06-09-2014, 01:39 PM.
                82 gs1100e FAUX Skunk
                80 gs1000s

                Comment

                • cowboyup3371
                  Forum LongTimer
                  Past Site Supporter
                  • Apr 2010
                  • 13998
                  • In Ohio Now

                  #9
                  The ones Ed linked you to will work just fine if you can make them yourself. If not, check out Z1's stock or some folks out here like Rennsports.
                  Cowboy Up or Quit. - Run Free Lou and Rest in Peace

                  1981 GS550T - My First
                  1981 GS550L - My Eldest Daughter's - Now Sold
                  2007 GSF1250SA Bandit - My touring bike

                  Sit tall in the saddle Hold your head up high
                  Keep your eyes fixed where the trail meets the sky and live like you ain't afraid to die
                  and don't be scared, just enjoy your ride - Chris Ledoux, "The Ride"

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                  • Gregory
                    Forum Sage
                    Past Site Supporter
                    • Sep 2012
                    • 2064
                    • Southlake - DFW - North Texas

                    #10
                    I went ahead and gambled $48 on a complete set (one 33" and three 22") of stainless from china. That is a fraction of the cost of those others. We will see how it goes.

                    I will just change all of them out on my daily rider and then use it's rear one on this project bike.
                    82 gs1100e FAUX Skunk
                    80 gs1000s

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