Should I rebuild these calipers?- Mtbr.com
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  1. #1
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    Should I rebuild these calipers?

    A buddy of mine just gave me his old '06 Juicy 7s... I currently have stock hydros (hayes sole).

    Anyway, they were his old brakes before upgrade and both calipers have issues. The front has a stuck piston which I have tried everything Avid recommends for stuck pistons and it will not free itself. Also, it does not seem either piston retracts all the way as I push them back as far as they go and I still get rub on the rotor. There is absolutly no play for centering the rotor as the pads are too close together. Also one of the pistons has a scratch on the top of it from where he was trying to push it back in with a screwdriver. Will this be an issue?

    The rear caliper has brake fluid leaking out of the piston... Obviously because of this there is no movement at all when lever is squeezed. Needs new seals I assume?

    My question... is it worth it? I would need to buy a juicy bleed kits and 2 sets of caliper seal kits. And I dont even know if this will fix the issue.

    Any opinions from anyone? I know if I can get these going they would be a huge upgrade over my Hayes Soles. But how much work am I looking at here?

    Thanks for the help

  2. #2
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    From the sound of it....

    you're not just looking at replacing seals but a complete caliper rebuild. It probably wouldn't hurt to rebuild the master cylanders (lever overhaul) either, but one thing at a time. You'll need a caliper rebuild kit. Any LBS should be able to get them for you. Or you can go here http://www.universalcycles.com/shopp...08&category=20 and order them on line. They'll only run you about $10 each and you'll need two obviously. You may also have to replace that piston. A scratched piston is not a good thing depending on where the scratch is located. You should NEVER use a screwdrive directly on the piston itself. A screwdriver can be used to push against the pads to move the pistons back into place. But if the pads are not installed then a 10 or 11mm open end wrench is the tool to use. Step by step instructions for the caliper overhaul are available on the Avid (SRAM) website under "service" Simply click on the Avid drop down menu and scroll down and click on "disc brakes'. Then scroll down and click on "2007 Avid Technical Manual" to download it. Follow the instructions for the caliper overhaul.

    From there you'll need the bleed kit of course. Bleed the brakes and see how they are. If you have other issues then you may need to rebuild the levers as well.

    Good Dirt
    "I do whatever my Rice Cripsies tell me to!"

  3. #3
    Meh.
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    If the piston won't push all the way back in, the system is probably overfilled. Open the bleed port at the lever and attempt to push the pistons back in. This will force out any excess fluid.

    If new non-OE pads are in the brakes, that may be why there's rub. Aftermarket pads are often too thick.

    If the scratch is on the TOP of the piston, no biggy. If it's on the side, replace.

    So you're looking at seal kits and maybe pistons. I'd say under 50 bucks for sure for parts.

    You'll probably need an air compressor to blow that seized piston out.

    Are the reservoir caps black? Or silver? If they are black and have a 2-piece clamp, they are 2004 brakes, not 2006. Good luck finding parts. 2004 was outsourced. After that, piston sizes, fittings, etc were changed.

  4. #4
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    Thanks

    Thanks for the link to the caliper rebuild kit. I never thought about the levers. I would prefer not to touch these so hopefully caliper is the issue.

    And thanks for the idea about them being overfilled. Ill try that. They are avid branded pads (definitely not the originals though) so I assume the pad thickness is fine. And they are 06s.

    Ive never had dual piston hydros (currently have single piston hayes sole) Should the pistons on the juicy 7s be flush with the caliper when fully retracted? Should the "nipple" on the piston be the only thing sticking out? Or should that nipple also fully retract into the caliper as well so the internal sides of the caliper are completly flat? Wish I would have took a picture (at work now).

    I assume they should be flush because getting the pads back in is a huge pain and they dont just easily slip in (get stuck on pistons when trying to push them in).

    Also, are there any online retailers who sell pistons for this model in case that scratch is an issue.

  5. #5
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    Also, how can i tell if the o-rings or seals are bad within the caliper? Would they just be worn down or am I looking for tears? The brakes are not that old ('06).

    The guy said it started leaking because he was trying to loosen the stuck piston by holding the unstuck one down and squeezing the lever, then all of a sudden fluid started coming out around the piston. Then he said screw it and gave em to me.

    I am going to open it up and look, but just wondering what Im looking for.

  6. #6
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    Oh my....

    sounds like he pushed the piston that he wasn't holding out of it's seat and that's why your having such a hard time getting it back in place and it's also most certainly the reason that it started leaking. My suggestion would be to rebuild the caliper. Don't even bother opening it up until you have the rebuild kit in hand. If indeed the piston has been pushed that far out, there's a good posibility that the seals have been damaged anyway. Just go ahead and get the rebuild kit and do the calipers. It isn't that hard and you'll have the peace of mind in knowing that things are as they should be. It's also much easier to find the cause for a stuck piston and fix it when you've got the caliper disassembled. It'll also be easier to assess that scratch on the one piston. So you may as well put in new seals etc. while you have em apart.

    As far as the new piston is concerned. I don't know of an online retailer that sells them. There may be, but not to my knowledge. You'll likely have to find a shop that deals in Avid brakes and have them order one for you if you need one. They're not that common of a replacement part so not likely not a "stocked" item. But you might get lucky, you never know.

    By the way, I'm an advocate of doing a complete rebuild of a hydro caliper or a hydro lever ANYTIME you take it apart. Of course you usually don't take em apart unless there's a problem to begin with. But as long as you're in there it's just good insurance.

    Good Dirt
    "I do whatever my Rice Cripsies tell me to!"

  7. #7
    Meh.
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    Any shop can order parts. BTI and QBP (distributors) both stock them.

    There are no specific SRAM dealers.

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