Cylinder in rear ATE brake | FerrariChat
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Cylinder in rear ATE brake

Discussion in '206/246' started by frankwissman, Aug 28, 2025 at 7:58 AM.

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  1. frankwissman

    frankwissman Karting

    May 6, 2006
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    Charleston, SC
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    Frank Wissman
    #1 frankwissman, Aug 28, 2025 at 7:58 AM
    Hi, Guys,

    I'm rebuilding my brakes and have hit a snag. The pistons were stuck and on two calipers, I had to block off the fluid passages and use a grease gun to pop the reluctant piston out. Now I must thoroughly clean everything before assembly. One cylinder in the piston, Item 10 in Tav 27, is stuck. The other three came apart easily. There is no access to the retaining clip, and when I use the irreplaceable screw, Item 22, Tav 27, to pull the cylinder out, I just can't with reasonable force. I am unable to locate 10 x 2 mm threaded rod to make a tool, the only thread I can find that size is Acme thread - rats. So - any ideas how to extract the adjustment cylinder?

    Thank you.
    Frank
     

    Attached Files:

  2. racerboy9

    racerboy9 F1 Rookie
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    #2 racerboy9, Aug 28, 2025 at 8:42 AM
  3. frankwissman

    frankwissman Karting

    May 6, 2006
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    Charleston, SC
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    Frank Wissman
    #3 frankwissman, Aug 28, 2025 at 12:31 PM
    Thank you - I'm stubborn, but now I know there is a better path than buying new calipers.
     
  4. racerboy9

    racerboy9 F1 Rookie
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    #4 racerboy9, Aug 28, 2025 at 3:53 PM
    I am definitely a do it your self guy but at 70 years old I am starting to choose my battles a little more. Plus they re-plate the calipers and have a guaranty.
     
  5. TonyL

    TonyL F1 Rookie

    Sep 27, 2007
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    #5 TonyL, Aug 28, 2025 at 4:25 PM
  6. swift53

    swift53 F1 Veteran
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    #6 swift53, Aug 28, 2025 at 5:37 PM
    Perhaps compressed air and a piece of wood between the pistons will do it. You can always re-insert the loose one, pressurize, and voila'....
    A grease gun lacks 150 PSI. Compressed air has always worked for me, 100%. But then, I have experience.

    There are many other ways, but if above your pay grade, a professional is advisable.
     
    TonyL likes this.
  7. frankwissman

    frankwissman Karting

    May 6, 2006
    68
    Charleston, SC
    Full Name:
    Frank Wissman
    #7 frankwissman, Aug 29, 2025 at 7:21 AM
  8. frankwissman

    frankwissman Karting

    May 6, 2006
    68
    Charleston, SC
    Full Name:
    Frank Wissman
    #8 frankwissman, Aug 29, 2025 at 7:34 AM
    That's how I started, but 150 psi didn't do it. My experience is a grease gun delivers significantly more pressure. The down side is the clean-up, of course. Also, when one piston is free, it seems to always move before the stuck one. That's why I broke the half apart and made these parts. They have a cork backing (didn't have sheet rubber on hand) and one is tapped 10 x 1 for the grease gun. It works.
     

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  9. pshoejberg

    pshoejberg Formula 3
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    #9 pshoejberg, Aug 29, 2025 at 7:54 AM
    Last edited: Aug 29, 2025 at 8:00 AM
    Hmm. I’m not sure I completely understand your problem. But if it’s one of the caliber piston’s that is stuck then you’re already informed about the way forward by others. You re-assemble the caliper and re-install the piston you blew out. Then you block the loose piston, with either a custom made tool or a clamp, and pressure out the stuck piston with air, grease, hydraulic fluid or a combination. Take extreme care of your fingers and eyes. Starting to work on the piston with mechanical tools will most likely damage the piston. New pistons are available with fair pricing so you can decide to roughneck it out but that’s not very rewarding.

    Best, Peter
     
    swift53 likes this.
  10. swift53

    swift53 F1 Veteran
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    #10 swift53, Aug 30, 2025 at 2:53 PM
    Love your solution, but mine is faster and zero machine work.
    I like your 'nose to the wheel' attitude. :)

    Regards, Alberto
     

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