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    rear caliper piston trashed?

    I attempted to grab this piston out of my rear caliper tonight. I think i boogered it up.

    If I did, where would you recommend getting a new one? Parts Outlaw?






    #2
    next time used compressed air to blow out the piston via the bleed port.

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      #3
      Seen Worse. The Important surface is the sealing surface. Piston appears to be almost clear of the bore. If the outer surface cleans up nicely with crocus cloth or a green scrubber, ya might be ok. What does the rest of the caliper and related components look like? Dust boot appears to be torn up, yes?

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        #4
        Yep, compressed air gets those out in a hurry. Just be careful, they shoot out with enough force to crush/lose a finger. To keep air in just one side of the caliper as you do this, put them back together with a piece of rubber or something blocking the brake fluid port.

        If the pistons are pitted (and there's better than even chance they are), you can get a piston and seal kit from an OEM parts supplier.
        Charles
        --
        1979 Suzuki GS850G

        Read BassCliff's GSR Greeting and Mega-Welcome!

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          #5
          One can also extract the pistons with caliper installed, pads removed. Place some rags / towels around the caliper, pistons forced out by pumping brake pedal. No danger of flying parts.

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            #6
            I ordered new seals from Z1 last week assuming I'd switch everything out.

            I haven't found only the pistons available online yet. I'll continue looking. Otherwise, am I looking at purchasing item 1-1 (part number 69100-34851) on this fische? I'd be buying the seals again, though. I guess it wouldn't hurt to have spares.

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              #7
              Originally posted by eil View Post
              Yep, compressed air gets those out in a hurry. Just be careful, they shoot out with enough force to crush/lose a finger. To keep air in just one side of the caliper as you do this, put them back together with a piece of rubber or something blocking the brake fluid port.

              If the pistons are pitted (and there's better than even chance they are), you can get a piston and seal kit from an OEM parts supplier.
              No doubt! I was pulsing one with air one time and I could see it flexing in and out....luckily I was smart enough to put a towel over it. It came out like a cannonball.
              One could lose some teeth like that.

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                #8
                Brake piston

                I once asked a machinist why they don't make these pistons out of a solid peice, apparently the caivity is to stop heat build up. But act as a moisture trap at the same time.

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                  #9
                  Originally posted by growler View Post
                  I ordered new seals from Z1 last week assuming I'd switch everything out.

                  I haven't found only the pistons available online yet. I'll continue looking. Otherwise, am I looking at purchasing item 1-1 (part number 69100-34851) on this fische? I'd be buying the seals again, though. I guess it wouldn't hurt to have spares.

                  http://www.partsoutlaw.com/oemparts/.../rear-calipers
                  Well huh. I am a little confused. I could have swore there was a piston and seal kit for the rear brakes on an 850. But looking through the fiches, I see only this "piston & pad" set. That will /probably/ contain pistons, seals, and brake pads. But you may want to call the vendor or wait for someone else here to confirm. (Fascinating that the pads alone appear to be $13 more expensive than the whole set...)

                  Also, make sure you get the pistons out so you can evaluate them before buying new ones. There's an outside chance they could still be good.
                  Last edited by eil; 07-08-2014, 11:23 AM.
                  Charles
                  --
                  1979 Suzuki GS850G

                  Read BassCliff's GSR Greeting and Mega-Welcome!

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                    #10
                    Originally posted by growler View Post
                    I think i boogered it up.
                    Can't tell if you boogered it or not.

                    We need to see the surface that is hidden by the dust boots.

                    The SIDES of the piston are what's really important.

                    If you need to get pistons, try Parts-n-More.
                    Go to page 2, scroll down just a bit, the are near the top of a long page.

                    .
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                      #11
                      1 tip for removal is to get 2 paint sticks and use them across the opening to "catch" the piston cups as the air pressure forces them out..
                      The 2 sticks are the perfect thickness to stop them just before they pop out - Using a towel to cover them also helps to prevent them cups from flying away when they pop out.
                      Be certain to have all your fingers out of the way when using air pressure - the cups will leave a permanent mark !

                      I have seen worse that cleaned up okay with a file / crocus cloth - as long as the sides aren't scarred it should work again...

                      Use brake fluid as a lubricant to push them back in once you change all the rubber bits

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                        #12
                        Originally posted by growler View Post
                        I attempted to grab this piston out of my rear caliper tonight. I think i boogered it up.

                        If I did, where would you recommend getting a new one? Parts Outlaw?


                        That doesn't look bad at all. As long as you didn't scar the piston where it rubs against the seal inside the caliper body you are fine. I would clean up the damage with a file or some wet/dry sandpaper sitting on a flat surface and reuse it.


                        Mark
                        1982 GS1100E
                        1998 ZX-6R
                        2005 KTM 450EXC

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                          #13
                          Great news. I'll use the air compressor method and use one of the methods listed so I don't injure myself. Once I get them out and cleaned up I will post more pictures. Thanks!

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                            #14
                            It may be the camera angle, but the piston looks a bit cocked in the bore

                            If so, straighten it out by turning the caliper piston side down on a block of wood and tap the outside of the caliper with a soft hammer until the piston pops back in

                            Some silicone spray on the piston circumferance first would help
                            1978 GS 1000 (since new)
                            1979 GS 1000 (The Fridge, superbike replica project)
                            1978 GS 1000 (parts)
                            1981 GS 850 (anyone want a project?)
                            1981 GPZ 550 (backroad screamer)
                            1970 450 Mk IIID (THUMP!)
                            2007 DRz 400S
                            1999 ATK 490ES
                            1994 DR 350SES

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                              #15
                              Can I soak the pistons in rust remover? Or just the little wire brush on a dremel to clean up the concave portion of the piston?

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