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  1. #1
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    Avid Elixir.. bleeding pain

    I am use to disk brakes that when they see your fingers coming, are just a light touch away from stopping - so I am trying to bleed a set of Avid Elixir on someone else's bike and the bleed bit seems easy and okay - The video by Scram make it nice and clear - BUT is there a procedure to get that last tiny, tiny bit of air out so that the bite starts earlier or is it just a case of letting the pistons come out a little with the wheel off and then bleed and gently ease them back in before fitting the wheels back on.

    Maybe I am expecting too much because on my bike with a set of Hope M6 & M4 the bite point is short, the amount of lever movement is also short and they just snap on those disks like a dog on heat.

    Cheers..

  2. #2
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    I had a pair of Elixir R's that had to be bled every 60-90 days for 2 years.....SRAM finally warrantied them with a new pair of X.0 Trails.
    I crashed hard enough on my Tallboy to break my leg,
    The carbon is way more durable than most people.

  3. #3
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    umm!.. I hope that is not the case with these as that would be a bummer.. especially as they are new.

  4. #4
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    Quote Originally Posted by EFMax View Post
    umm!.. I hope that is not the case with these as that would be a bummer.. especially as they are new.
    I haven't ever bled my Elixir Rs in two years and they work actually better the more I use them.

    I just got a bike with Maguras on it and they were weak and mushy and pretty horrid for a few rides. Now they work fine. No amount of futzing about will be the same as actually breaking the system in. Just make sure everything is straight to begin with.

    And the Avids were pretty horrid for the first while too. There's this idea that the perfect bleed will cure all ills - like the leeches they used in the 18th century.

  5. #5
    cowbell
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    I think comparing hopes to elixirs is a bad starting point. Do the Elixirs have a particularly mushy lever, or does it just have more travel than you think it should? I know a guy who fixed the travel issue by sanding one of his blocks down to do what you're talking about - let the piston out some, but obviously in a fairly controlled way. This allows more fluid in the brake, puts the piston a bit closer to the rotor to start, so there's less travel before he starts to get braking. But I think you may be looking at the way two different brakes work and wishing they were both the same, and the design simply doesn't allow the hopes and avids to feel the same to you.

  6. #6
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    Avid Elixir.. bleeding pain

    I run 4 sets of Avid hydros- Elixir CR, two sets of 5's and a set of Juicy 7's. On all of them I'd say that the pads make contact after pressing the brake lever ~1/3rd of the way which is fine by me.
    【ツ】 eDub 【ツ】

  7. #7
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    Quote Originally Posted by Cotharyus View Post
    I think comparing hopes to elixirs is a bad starting point. Do the Elixirs have a particularly mushy lever, or does it just have more travel than you think it should? I know a guy who fixed the travel issue by sanding one of his blocks down to do what you're talking about - let the piston out some, but obviously in a fairly controlled way. This allows more fluid in the brake, puts the piston a bit closer to the rotor to start, so there's less travel before he starts to get braking. But I think you may be looking at the way two different brakes work and wishing they were both the same, and the design simply doesn't allow the hopes and avids to feel the same to you.
    By blocks I assume that you mean the pistons? Making them shorter would have zip effect. More fluid in the system is irrelevant and will not result in less travel. The only way the piston will be closer to the rotor is due to pad wear. A shorter piston would just tend to cock in the bore more than it already does, which is pretty scary to start with.

    Travel will be determined by how far back the pistons retract. That will depend upon factors such as how flexible the seal is, how strong the spring is and how sticky the piston is in the bore. At the other end, the point at which pressure begins will be dependent upon the position of the bypass hole in the bore; it's fixed. Too much or not enough fluid can make it malfunction but that's not a fix for anything.

    I've found the Avid return spring to be inadequate and prone to only pushing on the top of the pads. I 'modify' mine to have about the same force as a Formula spring and things are less fussy now. The OEM spring is pretty comically engineered and then people re use them.

    Modifying the pistons for 'more fluid in the brake' is... well, counterproductive at best. People who couldn't engineer a brake should leave them as is.

  8. #8
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    Quote Originally Posted by bulerias View Post
    I 'modify' mine to have about the same force as a Formula spring and things are less fussy now.
    Care to elaborate on that mod? After just rebuilding my Elixir CR calipers and 1 lever, I'm interested to hear what you've done.

  9. #9
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    Quote Originally Posted by Oh My Sack! View Post
    Care to elaborate on that mod? After just rebuilding my Elixir CR calipers and 1 lever, I'm interested to hear what you've done.
    It's not really a modification but just a retensioning.

    As new, the tension at the very top of the pad is way higher than at the end of the skinny extensions that go down the ends of the pad. If you bend the end parts a bit further out they contribute some tension to the bottom of the pad, whereas originally they mostly just sit there. It's still nowhere near even, and it's pretty hard to come up with a design that will be - although Formula comes closer - but my pads wear more evenly now and things have been - strangely - quiet.

    Part of it is just riding regularly. Left to sit, the seals tend to stick to the cylinder walls and get cranky. Then things wear crooked and it's wallet time. I push the pistons in and out a bit every chain service or if the bike's been sitting [what?] and that seems to help too.

    I'm riding a borrowed bike with Maguras at the moment and they have no return springs at all. No glycol. One piece calliper. Seem to work fine, and fewer parts is always nice. When my Avids need serious work it looks like Magura time for me.

  10. #10
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    Quote Originally Posted by mtnbikej View Post
    I had a pair of Elixir R's that had to be bled every 60-90 days for 2 years.....SRAM finally warrantied them with a new pair of X.0 Trails.
    Yeah, I know the feeling! X.O Trails are great.

  11. #11
    cowbell
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    Quote Originally Posted by bulerias View Post
    By blocks I assume that you mean the pistons? Making them shorter would have zip effect. More fluid in the system is irrelevant and will not result in less travel. The only way the piston will be closer to the rotor is due to pad wear. A shorter piston would just tend to cock in the bore more than it already does, which is pretty scary to start with.
    No, by blocks I mean the "Bleed blocks" that you put in the caliper to keep the pistons from coming out when you bleed the brakes. I've I'd meant piston, I have said piston. I also think most people are smart enough to realize sanding the piston down to make it shorter would be....stupid.

    Now, think about what I'm saying. If the block you put in the caliper is (just a little) thinner, allowing the piston to be out just a little further when you do the bleed, there's just a little more volume INSIDE the closed system that holds the brake fluid. If you fill that space with fluid, the piston STARTS further out, thus it doesn't have to travel as far to push the pad onto the rotor. Thus you don't have to pull the lever as far before the braking starts.

    I hope that's clear enough. I kind of thought my first post was clear enough.

  12. #12
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    Quote Originally Posted by Cotharyus View Post
    No, by blocks I mean the "Bleed blocks" that you put in the caliper to keep the pistons from coming out when you bleed the brakes. I've I'd meant piston, I have said piston. I also think most people are smart enough to realize sanding the piston down to make it shorter would be....stupid.

    Now, think about what I'm saying. If the block you put in the caliper is (just a little) thinner, allowing the piston to be out just a little further when you do the bleed, there's just a little more volume INSIDE the closed system that holds the brake fluid. If you fill that space with fluid, the piston STARTS further out, thus it doesn't have to travel as far to push the pad onto the rotor. Thus you don't have to pull the lever as far before the braking starts.

    I hope that's clear enough. I kind of thought my first post was clear enough.
    Still doesn't work that way. Initially there is plenty enough fluid in the system to give a normal engagement point. As the pads wear, fluid will pass to the cylinders and there will be less in the reservoir. When it gets to the point that the engagement point starts to sag, you're usually at the point where the pad should be tossed.

    What you're saying is that the bleed blocks are made the wrong size, or that overfilling the system can be a good thing. And by your thinking, the brakes should take multiple pumps to work when the pads are worn. Or whatever.

    I just don't know what to say other than that how many initial lever strokes it takes to push the pistons out to where the pads contact the rotor has zip to do with engagement point after that. It's just hydraulics, pump and cylinder.

    As to your initial post, I guess I was trying to figure out how to make sense of something that still doesn't make sense to me, unless overfilling the system according to manufacturer's spec makes sense. Overfill it and then go out on a hot day and wail the brakes and maybe the fluid just expands to the point of lockup. ??Dunno, but somebody with a legal department to satisfy probably decided on the reservoir size and fill level.

  13. #13
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    Well I managed to get there in the end. Watched a different video on the bleed and I seemed to have missed out a couple of very small but important steps so all is good now and they are much better than when I first tried. Guess it is a patience thing and a learning curve to be discovered.

  14. #14
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    Bite point adjustment doesn't depend on bleeding. Neither does the amount of fluid in the system.

    After bleeding the brakes the pistons are retracted and will require a few pumps to make pad contact with the rotor. After pad contact the pistons retract a certain amount specific to the brakes you're using. As the pads wear, the pistons have to come further out of the caliper, but they still retract the same amount after pad contact. This is the self-adjusting nature of the brakes and means you get the same bite point regardless of pad wear.

    Some brakes have a bite point adjustment, others do not. If you want to change the bite point, you'll need a different set of brakes.

    As long as the feel is firm after pads make contact, your brakes are bled as they should and working as designed.

  15. #15
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    And that's pretty much what I told the guy who sanded down the bleed blocks. But he swears by it. I'm a farm boy. You'll get no arguments from me on how hydraulics work. :P

  16. #16
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    When all is said and done, there's a human being on the bike pulling those brake levers. If they believe something helps - and it doesn't do harm - no amount of physics or hydraulics can change that.

    Sanding down bleed blocks means you have a bit more fluid in the system, that's it. There's a range of acceptable amount of fluid in a hydraulic brake. Too little fluid means the master piston is pushing air and you lose braking power. Too much and the caliper pistons won't retract and the pads bind. Anything in between is fine and impossible to notice by the user.

  17. #17
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    Quote Originally Posted by EFMax View Post
    Well I managed to get there in the end. Watched a different video on the bleed and I seemed to have missed out a couple of very small but important steps so all is good now and they are much better than when I first tried. Guess it is a patience thing and a learning curve to be discovered.
    mind pasting which video worked better?

  18. #18
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    Quote Originally Posted by bulerias View Post
    It's not really a modification but just a retensioning.

    As new, the tension at the very top of the pad is way higher than at the end of the skinny extensions that go down the ends of the pad. If you bend the end parts a bit further out they contribute some tension to the bottom of the pad, whereas originally they mostly just sit there. It's still nowhere near even, and it's pretty hard to come up with a design that will be - although Formula comes closer - but my pads wear more evenly now and things have been - strangely - quiet.

    Part of it is just riding regularly. Left to sit, the seals tend to stick to the cylinder walls and get cranky. Then things wear crooked and it's wallet time. I push the pistons in and out a bit every chain service or if the bike's been sitting [what?] and that seems to help too.

    I'm riding a borrowed bike with Maguras at the moment and they have no return springs at all. No glycol. One piece calliper. Seem to work fine, and fewer parts is always nice. When my Avids need serious work it looks like Magura time for me.
    The spring you are referring to is not a return spring. It is a an anti-rattle spring. Since the pads float on the retaining pin, they would tend to rattle in the caliper when the brakes are not engaged. That spring provides just enough tension to keep them from rattling. The pistons are retracted by the seal, and the low pressure in the brake as the master cylinder piston returns to its original position.

  19. #19
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    Quote Originally Posted by Scotth72 View Post
    The spring you are referring to is not a return spring. It is a an anti-rattle spring. Since the pads float on the retaining pin, they would tend to rattle in the caliper when the brakes are not engaged. That spring provides just enough tension to keep them from rattling. The pistons are retracted by the seal, and the low pressure in the brake as the master cylinder piston returns to its original position.
    True, but my pads used to wear more at the bottom than the top before, and now they wear evenly. Stopped making [okay, almost] all those famous noises too. Could be coincidence, but the stock setup may not deal as well with keeping the piston straight in the bore. Which allows the seal to pull it back more evenly.

    All I know is that was the last thing I did dealing with the problems and it's been smooth sailing ever since. Cost in time and money is zero.

    And the pistons haven't stuck since either. Maybe just luck or coincidence, but worth a try. Look at a Formula return spring and see what they should have done; not perfect but closer, and still just a single piece of folded metal. Wish it fit.

    I'm not about to lie awake at night wondering how to make something that works in practice - for me anyway - work in theory.

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