[RezBomber offline]

so the problem for me is this. the rear brake caliper piston, is stuck, and when ever do manage to get one piston to be flush with the caliper, it moves out slightly by like 2 mms. then i get annoyed as my hard work on moving them goes out the window. the piston that gives me the problem is the one opposite from where the cable moves. i cleaned both pistons with rubbing alcohol. what should i do next? should i clean it next with a bit of grease on a Q-tip? should i push the pistons fully out to clean them? or do i have to get it serviced? just as a insight, this bikes rear derailluer was so dirty that i couldnt move the spinwheels with my fingers...

thanks for your help and feedback.

[schwim offline]

Wow, I've got an Elixir with a stuck caliper as well. I haven't really wanted to deal with disassembly, so I have just tolerated the less than stellar performance and noisiness. Let me know if you figure out an easy method of breaking it loose

[RezBomber offline]

im thinking of just, unscrewing the one screw that reqs. a hex key, and then slowly turning it so i can get a little room to see if i can pull the one piston out, since its not on the side of the cable thats giving me problems. then try to wipe it clean and then put the piston back...but before i try that idea out, i am still going to try and gently push it back, with screwdrivers.

[schwim offline]

I did push mine back when swapping pads(I had to or I wouldn't have been able to get it back over the rotor), but it didn't resolve the issue. The piston just extended again but does not retract, so it never keeps up it's end of the deal in the centering process.

[dgaddis offline]

im thinking of just, unscrewing the one screw that reqs. a hex key, and then slowly turning it so i can get a little room to see if i can pull the one piston out, since its not on the side of the cable thats giving me problems. then try to wipe it clean and then put the piston back...but before i try that idea out, i am still going to try and gently push it back, with screwdrivers.

It's a hydraulic brake, so it's a hose, not a cable, and that's important to remember. There's fluid behind the pistons, taking the caliper apart will mean you need to bleed the brakes. And you don't want to get that fluid on your bike or your skin, it's pretty nasty stuff.

That's probably exactly what it needs though. If it was so dirty the pulleys didn't spin on the derailleur, everything needs to be torn down and regreased and rebuilt.

Unless you have the tools, it's a job for the LBS.

Whatever you do, do NOT push directly on the piston with a screw driver, you'll damage the piston. Put an pad in, and push on the pad. That pad wont be any good for use anymore for braking tho, the screwdriver will damage the surface. You can reuse to for repositioning the pistons though.

[RezBomber offline]

yeah after my last attempt i looked at where the hose connected to the caliper, its rusty. so i guess ill have to take the brake off and send it to the LBS, but here i think they gave the shop set up for their "skiing" so ill have no bike service then. was thinking of just buying a whole new back brake set up, because i do have a few bucks laying around for emergency bike things. i was thinking of, Srams XO, because this weighs in as a cross-country bike. would i also need to buy a new rotor? or just keep the 160mm in the wheel? front brake is good, but in the spring i will send it in for bleeding.

[mtbgreg1 offline]

yeah after my last attempt i looked at where the hose connected to the caliper, its rusty. so i guess ill have to take the brake off and send it to the LBS, but here i think they gave the shop set up for their "skiing" so ill have no bike service then. was thinking of just buying a whole new back brake set up, because i do have a few bucks laying around for emergency bike things. i was thinking of, Srams XO, because this weighs in as a cross-country bike. would i also need to buy a new rotor? or just keep the 160mm in the wheel? front brake is good, but in the spring i will send it in for bleeding.

Whether or not you'd have to buy a new rotor depends mostly on what kind of condition it's in. If its in good condition then you should be fine with the old one

[dozzerboy offline]

If you want to bleed it yourself, avid's bleed kit comes with instructions that are easy to follow and they have a YouTube video too. If you do go this route. When you are "sucking" bubbles out take a small screwdriver and flip it to tap on the lever, hose, and caliper with the handle. This will shake loose the bubbles in the nooks and crannies. Might take you a few tries your first time but will get easier with time. Also, note what type of oil you're using. It should be DOT 5.1

[dgaddis offline]

SRAM X0 brakes are elixers. Don't buy a new brake, just fix the one you have. Either yourself, or at a shop. There's got a to be a shop not too far from you that'll do it for you.

[element22]

As with all brakes it sounds like the brakes need service..

We have a how to guide here on Singletracks.com

From what your saying it seems that one side of the caliper with a stuck or nearly stuck piston...Now what is happening there is more than likely a lack of lube...

First you need that tool that came with the brake ( that plastic fork looking item, called a pad spreader). Basically remove the brake from the frame and cycle the brakes back a forth a few times. (Squeeze the brakes till the pads come in contact with each other and then spread them back..

Now if you see that one side is moving a lot (possibly wanting to come out then STOP). You will have to carefully push that side back in.. Once it is all the way back in, remove the stuck side brake pad (for room) place either a rotor or something that can stop the good side from moving in the clearance groove of the caliper and cycle the brake again...Your looking to see if the stuck piston moves. Once it does carefully push it back and repeat...That should loosen it up.

replace the pad and re-center your brake.

[RezBomber offline]

so i took your advice element22. i kept pushing the pushing the piston out until it looked like it wanted to fully fall out, then i cleaned it, and slowly put it back in place. i did that for like 10 times. and when i get it close to 1mm to be flush, the piston gets flush with the calliper, then the piston moves back out my 1mm. this happens on both sides so the 2mm out push doesnt let me put the new brake pads in. :l

thanks for your help though. the pistons now run smoother.

[dozzerboy offline]

This sounds like a job for..... your local bike shop!!!!!

[schwim offline]

Now what is happening there is more than likely a lack of lube...

Hi there,

I might be missing something, but you don't mention lubing anything. Is the movement of the piston supposed to handle the lubing process through the brake fluid or are we supposed to lube the piston while it's extended?

Thanks for your time.

[element22]

You are correct...Do not add any lube....More than likely adding anything will attack the seals making it worse...

The action of the piston traveling back and forth will lube the seal with a small amount of brake fluid...Nothing should leak....

[schwim offline]

Thanks very much for the help. I'm going to try to get the piston loose on mine today and just wanted to make sure.