Juicy 3 - Pistons dont retract after bleed

chrisps
chrisps Posts: 60
edited September 2010 in MTB workshop & tech
Hi,

I have just tried to bleed my Juicy 3s for the first time. I followed the Avid instructions & video, however after the bleed, the pads were too close and the wheel wouldn't go back in. I figured that I must have over-filled the system, so undid the bleed ports, sucked a bit out, took the pads out and tried to push the pistons back with various implements, but they simply will not budge. I cant get them flush to the callipers and cant even get the pads (which are quite worn) back in now.

Any thoughts? :(

Also, before I did the bleed I tried to install some new superstar pads and I couldnt get them in because of the pistons, so I stuck my old pads back in and thought I would leave changing the pads for another day. Could this be indicative of a problem with the brake system?

Thanks!

Comments

  • mrwibble
    mrwibble Posts: 980
    I hope you literally didn't suck the fluid out! Could be stuck/dry seals on the piston or still too much fluid in the system.
  • chrisps
    chrisps Posts: 60
    Thanks for the reply; no, I didnt actually suck it out of the system! I re-attached the bleed kit, and gave a small pull on the syringe, as if I was trying to pull the air out.

    I then left the kit attached and open when trying to move the pistons.

    If there is still too much fluid in the system, how can I go about resolving that?

    Is there any way of telling if the seals are stuck? Surely with enough force they would budge?

    Thanks!
  • supersonic
    supersonic Posts: 82,708
    Take off the kit, leave the nipple open and then push them back in. Get ready to catch any excess.
    GT ZASKAR CARBON TEAM

    VOODOO CANZO

    Come and see me at https://www.facebook.com/biketyke/
  • chrisps
    chrisps Posts: 60
    I am pretty sure I tried that; I certainly had at least one nipple open; do both need to be open? Also, I presume that I am right in thinking that the pistons should go right back so that they dont stick out at all from the circular bit inside the calliper?

    Thanks!
  • supersonic
    supersonic Posts: 82,708
    Yes, they should be fully retracted - then a spacer fitted before the bleed. They can take som pretty extreme force! I'd just open the lever nipple.
    GT ZASKAR CARBON TEAM

    VOODOO CANZO

    Come and see me at https://www.facebook.com/biketyke/
  • nicklouse
    nicklouse Posts: 50,675
    chrisps wrote:
    I am pretty sure I tried that; I certainly had at least one nipple open; do both need to be open? Also, I presume that I am right in thinking that the pistons should go right back so that they dont stick out at all from the circular bit inside the calliper?

    Thanks!

    reading that tells me that you have not followed Avids bleeding info.

    Pistons need pushing back and held back before starting the bleed.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • chrisps
    chrisps Posts: 60
    Heya; I did try to do that actually; as I say, before I started the bleed I tried to install some Superstar pads with the intention of having those in and then using the red spacer thing. Unfortunately I couldnt get them to fit (the pistons werent quite flush). At the time I thought that it must just be an issue with the pads so I went back to the old pads and the red spacer. Once I had done the bleed it was quite difficult to get the spacer out and then the pads were too close together, hence my thought that I had overfilled the system....
  • chrisps
    chrisps Posts: 60
    Thanks for the comments everyone; turns out that I was a bit of a numpty; what I thought were the pistons (square bits) were actually the locator pegs. When I realised that the pistons were actually the round doughnut things, I could push them back moderately easily, so one disassembly and another bleed later, I have working disc brakes :)

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