I know usually when you have air in the line the lever will mush to the bar but it has very little movement in it as if there is too much fluid in the line. Is it possible that with the heat the fluid has expanded? If so what is the easiest way to let some of the fluid out and get the pistons/pads back flush in the caliper? Thanks

 

I tried letting some fluid out of the line which didn't do anything but I think let air in. I then did a full bleed and pulled quite a bit of air out especially at the lever. However, after I reinstalled the rear tire and brake pads and depressed the levers the pistons pressed up against the brake pads and stuck right there. They are not retracting back into the caliper once the lever is released. Any help is greatly appreciated.

 

I had this happen on my Elixir 5's. Sometimes the pistons get stuck and I think it's a separate issue from their air seepage problem. I performed a caliper overhaul, following the SRAM service manual provided online. Before doing that, try spraying some brake cleaner (or isopropyl alcohol) on the pistons and pushing them back in with a tire lever.

 

I ordered a piston overhaul kit (just the new seals) and am going to do the same since this seams to keep happening about every three or four months. Did you lubricate the new seals with the dot 5.1 before reinstalling the pistons? Also what is the best way to get get the pistons out minus an air compressor?

 

Yes lube the seals and Pistons with dot 3, 4 or 5.1 fluid.

 

Yep dirt over time in the seal interface, dirty fluid, or old seals that don't retract can cause this. Cleaning things up or replacing seals should help. Also make sure the lever retracts on its own irrespective of the caliper-- this may need cleaning too and is important for pad withdrawal.

 

you've already ordered the rebuild kit, but fyi, you could have attempted to massage (extend, retract, extend) the pistons one at a time a couple times each till they both extend/retract together the same amount. No biggie, replacing the piston seals is go to do as well. Make sure you put a little new/clean dot 5.1 on the seal/piston when reinstalling.

You can remove/replace one at a time it you don't have the tools to remove both at the same time. It takes a little longer but is just as effective.

 

Tonight i was able to remove the rear caliper and replace the piston seals along with the other little seals. I reinstalled the caliper to the bike and brake line. I then performed a full bleed. The results were a spongy but working rear brake. something still wasn't right though because the lever would still hit the grip when pressed. I then tried to bleed the lever by itself and tried to re pressurize the line. I either got full spongy again or too much pressure pushing the pistons too far out leading me to have to remove the rear wheel and brake pads to push the pistons back in. I then performed another full bleed. Now when I press the lever it does the same thing it bottoms out to the grip just barely providing enough force to stop the wheel. Any ideas what gives?

 

you still have air in the system. you must follow the directions for bleeding to a tee. Also, I think many (including myself) do not spend enough time or are not providing enough vacuum when pulling back on the plunger to remove air. You have to pull almost to the point that the plunger is going to come right out of the syringe, and do this several times. I also tap the caliper while doing this although its tough to do all this at once as you run out of hands. When I'm done with my bleed the first thing I do is remove the block and then gently pull the lever and watch the pistons. They should both extend together about the same amount, and then when I release the lever, they should retract a little as well. If not, massage them one at a time. It's a PITA but that's the drill.

 

I'm not really sure that pulling the plunger all the way back is that effective. I've never stopped seeing bubbles. I've pulled air out for 20 minutes and they just keep coming. Air seeps in from behind the plunger and I have a feeling bubbles are being pulled in at the bleed port as well.

I follow the bleed instructions verbatim except for one part. I extend the levers away from the bars for the bleed process rather than SRAM's prescribed distance. They engage too late for my taste and are too close to the grips by the time the pads bite. Any air that seeps in leads to no brakes pretty easily. By keeping the levers out and getting more fluid in the system, it gives you a little more breathing room.

 

likely the air is getting in at the fitting between the syringe and the bleed port as you have stated. that is a problem. I had found that my little o-ring on the fitting was not giving me a good seal and the same thing was happening to me. I removed the little rubber doughnut and wrapped in small piece of teflon tape. that worked like a charm, and I was able to get a good bleed. I also found that the speed at which I pulled the plunger back made a difference too. I tend to pull it back slow as I'm paranoid about pulling it out of the syringe altogether. after I've pulled it back 2-3 times and get used to how hard I need to pull it, I will do 1-2 quick pulls and sometimes get a few more little bubble to pop out. You have to get a better liquid tight fit on your syringe fitting and then I think you'll be all set.

 

Thank you for the teflon suggestion; I will give that a try. I have been using a box wrench to increase the torque on the fitting just past finger tight. My syringes feel like they have a built-in stop, preventing me from pulling the plunger out the back end. This is the "Professional" Avid bleed kit.

On a happy note, my Elixirs suddenly stopped giving me trouble 6 months ago. They just plain work now. No bleeding, no fuss. It's like there was some machining defect that got polished down through repeated use. I used to get sticky pistons and air contamination on weekly basis.

 

sometime things just fix themselves. congrats!

 

Well i did a full bleed today as per avid instructions to the t. I got all the air bubbles out of the caliper and lever. The result: either a spongy front lever not activating the pistons enough to squeeze the pads or a firmness at the lever along with pistons not retracting. Keep in mind I just did a caliper seal overhaul on this rear caliper. I have no Idea what to do next. When the pistons wont retract i remove the rear wheel and push them in with a screwdriver. Then I reinstall the rear wheel and its mush at the lever with no braking power. Then the next time I squeeze the lever it firms up but the pistons now wont retract into the caliper causing me to have to drop the rear wheel and push the pistons in again. Any ideas? I will post this in my other thread too. Thanks

 

try to keep things on one thread as it is the same issue.

not sure why when you pull the wheel and retract the pistons manually that that would cause the system to get mushy (from originally being firm). possibly the pistons themselves have deteriorated, and need replaced. At this point, you may want to look at replacement alternatives (not sure how old this brake set is or how many miles). You don't have to replace the front if that is working well, so you'd just be looking at replacing the rear brake set, or replace the pistons and hope that that was your problem (no guarantees).

 

So I bought an avid pro bleed kit thinking maybe my old basic bleed kit was the cause of not being able to get a good bleed on two different rear elixir calipers and levers. I still cannot get the rear lever to firm up any after the bleed and I was pulling air out of the caliper forever. I simply dont understand this. I have successfully done this before but this time is different for some reason. I am following the directions and somehow there is still air in the line at the end of the bleed. Im about to give up! Where can the additional air be coming from?

 

A stuck Avid brake, really?...

Guess you don't have Google round your way?

 

If you keep pulling air then you have a bad seal etc somewhere in the system.

 

try replacing the pistons. They may have worn a step in them and keep getting stuck. Don't try sanding it or anything because it will ruin the tolerances but try new pistons and while you're at it attach pictures of the old ones.