Disc brake pistons not retracting

Posted on
  • I made a stupid mistake when bleeding my Shimano 105 disc brakes – used the disc spacer instead of a bleed block in the calliper when doing the bleed. So after pulling the brake lever to get the air out the system, the pistons have come out (presumably further than they should) and now I can’t get them back in far enough to refit the brake pads.

    I’ve tried getting different tools in the calliper to push the pistons back, which helped a bit but not enough.

    Has my stupid mistake resulted in unrepairable damage to the seals, meaning unfixable? Or does anyone have any advice for easing them back in?

    I came across some stuff online that talks about cleaning the pistons with mineral oil, so will try that next. But they’re brand new callipers so dirt isn’t going to be an issue.

    Thanks for any help!


Disc brake pistons not retracting

Posted by Avatar for youth7 @youth7