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Juicy 3.5, big "dead zone"

stuart_c-2stuart_c-2 Posts: 805
edited July 2010 in MTB workshop & tech
Yes, another thread about bleeding brakes.

Just bled my rear brake, an Avid Juicy 3.5, as the hot weather seemed to make it pressure up and drag. Could hardly turn wheel before I did it.

Well, I've bled it as per Parktool website and now it has a big dead spot before it bites, when it does bite it bites well and the lever feels strong (not much give), but it's very close to the bar. I used the big red spacer that was in the kit, it was marked as Juicy 5,7,Alt and Elix but no mention of 3. Would that bare any relevance? I had to shove the pistons right back to get it in and it was still a tight fit.

Also, the instructions on the Avid site show the bleed port on the Juicy's as being in a banjo bolt, but on mine the bleed port is actually part of the caliper body?

Should I be using the red spacer, or just do it with the wheel in?

Cheers
"I ride to eat"

Posts

  • nicklousenicklouse Posts: 50,675 Lives Here
    sounds like you still need to set the pistons.

    yes the bleed port should be part of the banjo.

    what year is your calliper? pics?

    spacer in but then you need to reset the pistons.

    I take it you have not read the Avid bled info?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • AnonymousAnonymous Posts: 79,667
    If the hot weather makes the pistons extend, then you must have air in the system. The brake fluid should be completely stable at normal atmospheric temperatures.
  • stuart_c-2stuart_c-2 Posts: 805
    nicklouse, here’s a pic of the calliper. Bleed port in the body, hose goes straight into top of calliper body, behind the mounting bolt. They’re fitted to an 09 Scale. I haven’t read the Avid stuff about piston setting, I’m guessing I’m a dope and need to? :oops:

    caliper.jpg

    yeehaamcgee, I know, hence why I bled it. :wink:

    Cheers

    Stu
    "I ride to eat"
  • stuart_c-2stuart_c-2 Posts: 805
    Ok, so I tried advancing the pistons by pumping the lever with no wheel in (as per Avid website), but it seemed to make no difference. Looks like another go at bleeding is in order.

    I notice that on the bleeding guide on this site and on Parktool site that they just leave the wheel in on there pictures? Is it worth doing it with the wheel and pads in place, or do I HAVE to take them out and use the big red spacer? I know there is a risk of contamination if I leave the pads and wheel in, but will it affect the bleed?

    Cheers

    Stu
    "I ride to eat"
  • diydiy Posts: 6,473
    Follow the SRAM video for bleeding

    http://www.youtube.com/watch?v=6mg6NbIjmOM

    They advise some de-gassed fluid in the lever syringe to avoid sucking air in when you bleed the caliper.

    Edit:

    I think this from park tool might be the problem..

    "3. Rotate brake lever so it points straight to the ground. Remove lever bleed-port plug from lever using a T-10 star-driver (found on the TWS-2). Insert the empty syringe into the lever bleed port and secure (Figure 3). Open hose clamp. The lever syringe will accept the overflow from the rear syringe during the bleeding process. Use a toe strap or thick rubber band to close lever fully to bar or grip. (Note: if lever does not fully bottom against grip, check location of reach adjustment screw. Thread screw so it clears lever body if necessary.) "

    and later they say

    5. At caliper, hold syringe vertical and open tubing clip. Remove any air in the caliper body by first pulling back on plunger gently (Figure 4).

    I think this is a mistake - I would say it is almost guaranteed to suck air in to the system at the lever. I'm also not entirely convince that you should have the lever rotated to the ground either.
  • rudedogrudedog Posts: 523
    diy wrote:
    Follow the SRAM video for bleeding

    http://www.youtube.com/watch?v=6mg6NbIjmOM

    They advise some de-gassed fluid in the lever syringe to avoid sucking air in when you bleed the caliper.

    Edit:

    I think this from park tool might be the problem..

    "3. Rotate brake lever so it points straight to the ground. Remove lever bleed-port plug from lever using a T-10 star-driver (found on the TWS-2). Insert the empty syringe into the lever bleed port and secure (Figure 3). Open hose clamp. The lever syringe will accept the overflow from the rear syringe during the bleeding process. Use a toe strap or thick rubber band to close lever fully to bar or grip. (Note: if lever does not fully bottom against grip, check location of reach adjustment screw. Thread screw so it clears lever body if necessary.) "

    and later they say

    5. At caliper, hold syringe vertical and open tubing clip. Remove any air in the caliper body by first pulling back on plunger gently (Figure 4).

    I think this is a mistake - I would say it is almost guaranteed to suck air in to the system at the lever. I'm also not entirely convince that you should have the lever rotated to the ground either
    .

    It shouldn't if you have the lever syringe clamp closed
  • AnonymousAnonymous Posts: 79,667
    I just followed the Avid bleed kit instructions precisely and it did the job for me. No need to rotate the levers. I did have to take the callipers off to get the block inserted. I think it was the red one I used on my Juicy 3, though could have been the black one. Basically whichever one fits. I did have to push the pistons back.

    I never advanced them forward though and don't think you should have to. Squeezing the levers with no wheel or blocks in place just leads to a world of pain for me. Though saying that, during the procedure you do have to get the lever to the bar when the syringes are attached, but the pressure is out of the system so it doesn't push the piston. You then use the opposite syringe to push the lever back to fully extended.

    As for pulling the syringe back, as per the Avid instructions, just don't pull it back so far that it goes past the back seal. Other than that just ensure the clamp on the other syringe is closed.
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