Another Avid Elixir brake issue
I have the Avid Elixir R. I tried to change the pads, but one of the pistons wouldn't return flush into the caliper. So I bled the system, following the Avid manual with 1/2 and 1/4 syringes of DOT 5.1. I can now get the rotor into the pads/caliper.
But now I am getting some drag (didn't have this before). The rotor is fairly true, but I think the pads should be a little further apart for better clearance. Also the levers throw is less than before now.
So I have some options:
1. re-bleeding the system. Using less fluid than recommended, since the brake fluid is new. Is this doable?
(There seems to be air in the system. If I tilt the bike, into a wheelie of about 90 degrees. I can slowly pull the brake to nearly the lever. It take about 5 pumps of the lever.)
2. open the brake lever port and push the pistons in. Hoping that some fluid comes out. Proving that there was some overfill.
3. may be doing both of the above.
4. lubricate the pistons?
5, Worse case: take about the calipers and levers
I have been trying to read other posts on this topic and it gets pretty overwhelming.
Anything else I might want to do?
Tomorrow, I hope to do a quick ride and hopefully break in the pads. I wonder if that will do anything.
I am having some what the same issue with dragging, noise and here is an email I got from SRAM today regarding the issue. Not sure if this will help at all?
A piston may be jamming in the caliper, which would bend the rotor and cause vibration. Make sure both pistons are moving, and if one is stuck, hold the moving piston in place with a wrench while squeezing the lever. Once the stuck piston starts moving again, lubricate it with DOT fluid and push it back into the caliper. You may have to repeat a few times.
Or you can just take the caliper apart and replace the seals. The o-ring kits are cheap. You could also try just cleaning and reinstalling the existing piston o-rings. Check to be sure it hasn't deformed, and be sure to thoroughly clean the caliper body too.
It IS a pain to rebleed once you've got it back together, as there will be a huge air pocket in the caliper body. Just plan on spending some extra time bleeding the caliper end.
@nov0798 pistons are moving equally.
@dirtyjack I am going to take the caliper apart as a last resort!!
I went for a short ride today with my new front pads that involved quite a bit of downhill braking. No squealing!!
I started with some drag throughout the wheel's revolution. Only noticeable with the wheel spun off the ground. Didn't feel it or hear anything when riding.
Well after the ride, I spun the wheel and now only one area with some drag. Hmm, going for a ride seems to have improved the brake spacing.
When I lift the bike up into a wheelie, I can still get the lever to pull closer and closer to the grip. But when I drop the front end, the brake firms up again.
I guess I will keep this set up for now. We are getting some rain and I won't be doing too much riding for a bit. Now I am going to change the rear pads. I hope the pistons go back in and don't stick. Or I am bleeding again!
I spent maybe 10 hours on trying to fix a pair of Elixir CR and pair of Elixir 5 and I never came close to a perfect result. I bled the entire system maybe 3 times for each brakes and nothing would make it better. I even fully disassembled the calipers, got the pistons out (you need a compressor for that), cleaned everything and reassembled –*it wasn't any better.
It turns out my rotors were slightly warped, less than 1mm but because each brake pad doesn't withdraw more than a fraction of a millimeter the slightest warp makes the caliper impossible to adjust.
I search this forum inside out and then went to 4 bike shops to talk with mechanics about the problem. It turns out that most Elixir brakes get sticky after a year of use. If the pistons are not withdrawing it's because a part of the master cylinder spring doesn't to its job. It can be because the assembly gets sticky due to some plastic or rubber bushing getting either porous or dirty or because the spring is weak.
I was advised to spay Teflon lubricants on the master cylinder shaft (base of the lever) – I tried and it didn't make anything better.
SO... the solution seems to be to replace the master cylinder. It cost $29 at bikebling for one rebuild assembly. Cheaper than new brakes BUT certainly a headache at assemble. I'm going to order one for my front brakes who keeps rubbing and gets on my nerves every time I ride.
Man, I totally feel your pain...
I have 2011 XO's, just before the redesign of course, and have been battling similar drag and inconsistent lever feel issues for the last several months (about six hard months of use into the brakes' lives). Here's what I've found:
First, bleeding them is a mofo, plain & simple. You can do it absolutely to the letter and still end up with a tiny air bubble or two that once it makes its way to the wrong place will cause weirdness. My theory is that the rubber diaphragm that expands/contracts when the adjusters are dialed (effectively changing the volume of the master cyl) just traps little bubbles by nature. Tapping and dialing the adjustable barrel while bleeding seems to net the best results, but as the OP noted the true test of the bleed comes when you stand the bike up THEN apply the brakes. If the lever changes engagement point, you've still got too much air inside.
Second, the caliper pistons do get sticky with use. I made the mistake of letting my rear brake pads wear too far and as the pistons came further and further out of their comfy caliper home, things got really bad. The first thing I noticed was that the lever had become REALLY inconsistent, like normal engagement one minute and all the way to the bar the next; sometimes I could pump pressure back w/ a few squeezes, other times it would come back on its own. I had replaced the pads fairly recently, or so I thought, so like an idiot I assumed it was a bleed issue and ventured on, only to have the pads go metal-to-metal mid-ride. Apparently when this happens one piston can extend far enough to force the rotor into the side of the caliper, then freeze in this one-piston-extended-one-piston-compressed state. I had to unbolt the caliper to get home, then removed the remains of pads (obviously), blasted everything as clean as possible with alchohol base 'a/c flush' (California-fied brake cleaner) while agitating gently with a soft bristle brush (small paint brush); I dried everything w/ a blow gun, then soaked the pistons/seals/caliper with brake fluid. Before installing the new pads I also lubed the cone washers for the caliper mount (CPS or whatever they're called) - it seemed that as I would torque them down they weren't staying true, even though the brake lever was squeezed tight I could see the caliper trying to move and rotate as the mounting bolts were tightened, and a little penetrating lube seemed to free that up.
Finally, I've learned that there's only so much you can do - if you're pretty confident you've got the bleed done right, and you've got NEW pads installed, you gotta' just ride it. For whatever reason they seem to just bed themselves in on their own after a couple rides. It's frustrating as hell to not get the feel you're looking for in the work stand, but from my experience as the brakes age it's easy to over-adjust them. If they drag just a bit, like spinning the wheel still results in some actual 'spin', give 'em a little time and see how it goes. Also, a quick 'trail bleed' method I've found that seems to work with all Avid/Sram adjustable brakes is to crank the adjusters in & out while pumping the lever - this will usually firm up a soft lever feel immediately and if it stays that way, great; if it goes spongey again immediately, you need to re-bleed.
Bottom line is you're doing everything right from what I can gather, maybe have another go at bleeding the front if it's going wonky when wheelieing, but don't expect them to feel perfect until you've put a little mileage on them. If you haven't already, definitely lube the pistons w/ some DOT5 while you're bleeding them, and by all means keep close track of pad wear. Once the brake do start working normally again, your first sign of wear will be inconsistent lever feel coming back. Depending on how/how much you ride this may not be for many months, perhaps a year or more, so try to remind yourself somehow. But I've learned that as the pistons extend to cover pad wear, a perfect feeling brake will give you a 'whoa' moment out of the blue as one side sticks.
Too bad they work so well when they work, God knows I've wanted to scrap mine more than once during my learning process, but when they're on they're just so good! The non-adjustable types are probably much easier to live with bleed-wise, but cleaning and lubing pistons with every pad replacement is probably good practice for all models (perhaps brands too - I remember doing the same thing on my old Shimano XT's back in the day).
@eric - great write up!!
Thanks for input guys. It is nice to share the pain!
May be I need to pick up another hobby or go get some Avid BB7!!
I had some Formula Oros on a previous bike that I bled once with their instructions. It didn't develop air in the line. With their instructions, you have to have the bleed ports in certain positions. In fact, in their current manual, they recommend taking them off the bike and using a stand!!
So may be, it would be easier to bleed the Avids off the bike.
Tomorrow, I hope to work on my rear brake. This one needs a bleed, too. one piston is about 1-2mm out. Why couldn't changing pads be easier???
With my front brake working, even with air in the line, do I risk total brake fail on a super long downhill? Or should I torture myself with another bleed??
is turning a big gear
Last edited by estabro; 01-20-2012 at 11:10 AM.
Get it unlocked.
'...With my front brake working, even with air in the line, do I risk total brake fail on a super long downhill? Or should I torture myself with another bleed?? ...'.
If you have new pads and are able to pump up some stopping pressure AND you HAD TO decend a super long downhill to, say, get home or save a drowning witch or something, I'd say yeah, you'd probably survive. However, based on my recent total brake fail experience I strongly recommend you play it safe and re-bleed.
As you mentioned, just bite the bullet and remove the calipers if nec, remove the pads and pump each piston out as far as possible and clean/lube 'em up, then slide the Avid bleed block in and do each end methodically. It's actually quicker than you think, especially now that you've done it. Remember to leave the pad engagement as loose/close to the bars as you can stand for the first ride (or part of ride) - that'll help minimize the drag as the pads & calipers seat-in. Once everything is settled and feeling consistent, THEN start playing with the adjusters; and even then, try to make minor adjustments and leave it alone for a bit. Like I say, my theory is the rubber bladder inside the lever/master cyl pops off tiny bubbles when you dial it so you gotta' give it a little while to settle sometimes.
Came across this thread as I was trying to bleed my brakes...done it several times on two bikes, but this time it was not working (major rub no matter how I adjusted the caliper and the handle pulling into the grip)...thanks to the info on this thread I saw that the two pistons were not moving equally. I help the good one in with pliers and pushed the other one out, cleaned and lubed with the DOT5.1 (repeated this a few times) then repeated the process with both pistons (a couple time) until it looked like they were in sync, then, I re-bled the system and POW! As good as new. Might have to invest in an o-ring kit in the future...nah, when it gets to that point, that will be my excuse to upgrade to XT's.
Thanks for all the advice here. It saved me at minimum a trip to the LBS and ~70, and at most, new brakes (that now can be put off for a while. Again, Muchas Gracias!!!
It's fun when you can dial in your own gear. I finally was able to get mine working better, by taking the calipers off the frame and rebleeding that way.
Actually, taking the caliper off is part of the Avid procedure (which I don't do), but I have not had any issues with air getting held up in there. I've heard of others putting their bike in all kinds of orientations to accomplish the same thing.
Good job S.O.B. I had to do this last year and after cleaning up stuck piston my brakes worked flawlessly all season. Although the level pulling to the grip was not likely fixed by cleaning up the sticky piston as that is classic air in the system symptom. Glad to hear you got it working!
Thanks. Yeah, I was not exactly clear in the order of things. My lever did not always pull into my grip...just sometimes just dug into my fingers a bit. I was told that I definitely had an air bubble for that to happen. Sucks to be riding down a hill, brakes working fine (or at least o.k.), then suddenly you need to move your fingers out of the way and pull the brake into the grip for it to work. A bad/late brake on some trails in Auburn could mean tumbling down a steep ravine....and if you are fortunate enough to survive the rocky fall, you will most likely drown when you hit the river.
Anyway, when I finally fixed the stuck piston, that is when I noticed the lever came all the way to the grip. I figure when I kept pushing the pistons out, then forcing them back in, I might have gone a little to far and let air into the system some how (don't know if that makes sense or not). Regardless, I bled the brakes after fixing the piston (careful to do a thorough job, so I did remove the caliper and hold it while bleeding) and now they work fantastic. So, two problems with the same brake, both fixed in just over an hour thanks to the forum contributions on MTBR (and this was not the first time).
Originally Posted by S.O.B.
Tips on how to repair leaking or failing brake calipers using rebuild kit.
After bleeding my Elixir R brakes to the T, one bleed block came out while bleeding the master cylinder/lever, causing the piston on the outer side to come out. Fluid leaked all over. I pushed the piston back in and called SRAM, who told me the seal is bad inside. 4 years without a bleed or rebuild and it is time. I ordered the rebuild kit for the Elixirs and read about using RRG above, to prevent sticking of the pistons.
I never had any rear brake power, which prompted me to try bleeding. Figure on rebuilding every year at the least. Just a bad design IMO. DOT fluid like that used on the Avids, must eat away at the seals inside. RRG has a mineral oil content, which does not eat away at seals, and is resistant to heat as well, protecting the seals from the degradation caused by the petroleum based DOT fluid. Perhaps Shimano has the best idea with mineral oil in their system. Not sure if mtn. bike calipers get hot like cars/motorcycles, necessitating DOT fluid in their use.
Anyhow, I'll see how the rebuild kit goes. Have to remember to line the grooves in the pistons vertically with the caliper when pushing the pistons in. Should be interesting.
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