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Rear brake refurbished STILL NOT ENOUGH BITE

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    Rear brake refurbished STILL NOT ENOUGH BITE

    Hello everyone. During those crazy lockdown times we all live in I decided to dive into my GS550E rear brake system in anticipation of summer and freedom at last. I removed the caliper and the master cylinder cleaned them meticulously using vinegar baths and compressed air. Rebuilded both of them with TOURMAX rebuilt kits. Also Installed SS brake line from VENHILL. I bled the system but what I have now is the following. I press the pedal it goes down a little bit and THEN pushes the pistons out and if I release it and push it again quickly it gets WAY stiffer and has more bite. I let it sit for five minutes the sponginess returns. Any ideas as to what’s going on? I also Zip tied the pedal down for the night because I remember months ago I saw this tip on another thread.! I really like using the rear to control the bike bcs the place I live has very narrow and small backroads.! Thanks in andvance!
    GS674 Hybrid -1965 Vespa 90 -1958 BMW R26

    #2
    Originally posted by Kara25 View Post
    ...if I release it and push it again quickly it gets WAY stiffer and has more bite.
    Sounds like there's still air in the system.
    1982 GS1100E V&H "SS" exhaust, APE pods, 1150 oil cooler, 140 speedo, 99.3 rear wheel HP, black engine, '83 red

    2016 XL883L sigpic Two-tone blue and white. Almost 42 hp! Status: destroyed, now owned by the insurance company. The hole in my memory starts an hour before the accident and ends 24 hours after.

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      #3
      Thanks Rob the thought crossed my mind too but I can’t understand how is it possible to still have bubbles after all that bleeding. That’s why I zip tied the pedal in a last ditch attempt to remove them overnight!
      GS674 Hybrid -1965 Vespa 90 -1958 BMW R26

      Comment


        #4
        Air is surely a possible, but also see if the pistons are pulling back further than normal.
        The piston may not be sliding smoothly in the seal, the seal pulls it back.

        Just a thought. Seen it more than once on the fronts.

        Don't know anything about TOURMAX rebuilt kits, as OEM is generally the way to go.
        Bob T. ~~ Play the GSR weekly photo game: Pic of Week Game
        '83 GS1100E ~ '24 Triumph Speed 400 ~ '01 TRIUMPH TT600 ~ '67 HONDA CUB

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          #5
          The rear caliper can be awkward to get rid of the last bubble of air.
          Sometimes I've had to take it off the bike and hold it in various positions to coax that bubble to the bleed nipple(s)
          ---- Dave
          79 GS850N - Might be a trike soon.
          80 GS850T Single HIF38 S.U. SH775, Tow bar, Pantera II. Gnarly workhorse & daily driver.
          79 XS650SE - Pragmatic Ratter - goes better than a manky old twin should.
          92 XJ900F - Fairly Stock, for now.

          Only a dog knows why a motorcyclist sticks his head out of a car window

          Comment


            #6
            Originally posted by Baatfam View Post
            Don't know anything about TOURMAX rebuilt kits, as OEM is generally the way to go.
            IMO tourmax are good quality and made in Japan have them on my 850 braking system for years with no problems
            The big guy up there rides a Suzuki (this I know)
            1981 gs850gx

            1999 RF900
            past bikes. RF900
            TL1000s
            Hayabusa
            gsx 750f x2
            197cc Francis Barnett
            various British nails

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              #7
              Originally posted by fastbysuzuki View Post
              IMO tourmax are good quality and made in Japan have them on my 850 braking system for years with no problems
              Good to know, thanks....
              Bob T. ~~ Play the GSR weekly photo game: Pic of Week Game
              '83 GS1100E ~ '24 Triumph Speed 400 ~ '01 TRIUMPH TT600 ~ '67 HONDA CUB

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                #8
                The problem is the aftermarket seal parts. They are too tight and won't allow the piston to move out closer to the disc the way they should. You had the right idea about pumping up the system and locking the pedal down over night but if the seals are "really tight" even that doesn't work. I'd try again, pumping up the system as much as you can. Or better yet, get OEM Suzuki parts.
                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


                  #9
                  Thank you everyone for your insight.Gonna have a cup of coffee and see if i have any difference after zip/tying the pedal overnight.Reporting back later!
                  GS674 Hybrid -1965 Vespa 90 -1958 BMW R26

                  Comment


                    #10
                    UPDATE. Big improvement with zip tie overnight trick. Initial sponginess before movement of pistons is gone now the bike stops depending the power you use on the pedal. Still not locking the wheel though. I think I am expecting too much from those calipers. Also thinking of cleaning the disc using green scotch brite cause they seem to have past brake pad residue on them EDIT: during refurbish I DID NOT CHANGE brake pads cause they seemed beefy enough with still lots of meat left on them.
                    Last edited by Kara25; 03-09-2021, 04:32 AM.
                    GS674 Hybrid -1965 Vespa 90 -1958 BMW R26

                    Comment


                      #11
                      Originally posted by Kara25 View Post
                      UPDATE. Big improvement with zip tie overnight trick. Initial sponginess before movement of pistons is gone now the bike stops depending the power you use on the pedal. Still not locking the wheel though. I think I am expecting too much from those calipers. Also thinking of cleaning the disc using green scotch brite cause they seem to have past brake pad residue on them EDIT: during refurbish I DID NOT CHANGE brake pads cause they seemed beefy enough with still lots of meat left on them.
                      Good. Glad you're getting there.

                      Consider changing the pads anyway. New pads can make a significant difference, especially if yours are 25+ years old.
                      Bob T. ~~ Play the GSR weekly photo game: Pic of Week Game
                      '83 GS1100E ~ '24 Triumph Speed 400 ~ '01 TRIUMPH TT600 ~ '67 HONDA CUB

                      Comment


                        #12
                        It should lock the rear wheel.
                        If they are oily-contaminated, solvents may drive the contamination INTO the pad. but, Alcohol(methyl or ethyl or iso for backrub) will take grunge off your disk without leaving any residue.
                        You can try to sand or file the pads if they are really bad. Use flat backing-block for sandpaper to keep the pads flat.
                        extra complications
                        If there are deep grooves in the pad, filing or sanding will remove them ..so, the gouged brake disk will need time to re-imprint them for full stopping power.
                        IF your pads are not perfectly aligning to the disk, (a little wedge-shaped) fix this, or be careful to A) mark the pads per side and B)keep the same tilt when sanding-filing.
                        SAFETY First: wear a mask for dust, vacuum during and after...

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                          #13
                          So I think I goofed up on buying new pads and be done with the overhaul. A quick search on the internet pointed out that those goldfren type 076 pads will fit my rear caliper. Upon trying to install them they are not long enough for the two holes to match the guides on the caliper that the pads travel upon. �� Any good recommendation for pads that will surely fit on a 550E rear??
                          Last edited by Kara25; 03-10-2021, 05:54 AM.
                          GS674 Hybrid -1965 Vespa 90 -1958 BMW R26

                          Comment


                            #14
                            You can get pads at Z1 but can you post a picture of how the pads you have are sitting in the caliper?
                            Last edited by cowboyup3371; 03-10-2021, 07:25 AM.
                            sigpic
                            Cowboy Up or Quit. - Run Free Lou and Rest in Peace

                            1981 GS550T - My First
                            1981 GS550L - My Eldest Daughter's
                            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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                              #15
                              I would have posted pics cowboy but I am getting constant errors when I try to upload from my iPhone.the pads are shorter hole to hole from the ones that are already on the bike. What a stupid mistake now I am stuck with brand new pads that I can’t use. What *@%^$*@%^$*@%^$*@%^$es me off is that their site had the GS550E in the compatibility list with those particular goldfren pads
                              GS674 Hybrid -1965 Vespa 90 -1958 BMW R26

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