[kail]

Hey guys, I'll just cut right to the chase:

My Avid Elixir 7 front brake has had issues for several months now. Namely, as it heats up from a few minutes of DH, the reach keeps getting further and further out. Normally, I just stop and readjust the reach and it's good for the rest of most rides. I know it's just air in the system causing it.

However, I have an enduro race coming up this Saturday with a couple real downhills in it (both of the trails used to be actual DH courses that I've raced in the past). Needless to say, I can't stop and readjust my brakes -- nor can I start the downhill sections with the reach way in to compensate for the expansion. Both trails start with VERY steep and gnarly sections.

So I borrowed my friend's Avid bleed kit the other day and watched several Youtube videos put out by Sram/Avid. I prepped both syringes just like they showed and followed every procedure perfectly, as far as I can tell. Anyway, when it came time to push the 1/2 full syringe at the caliper up to the 1/4 full syringe at the lever -- I couldn't get ANY fluid to go in. I tried removing the piston block and then it would push the pistons out...but none would go up into the lever syringe. I put the piston block back in and it was as before -- no fluid would move. So then I thought I'd scrap that idea and just try to suck air out of the lever end.

I re-installed the caliper screw and tried pulling up on the lever syringe to create a vacuum. Well, air certainly came out of the lever. Once the air bubbles rose to the top of the fluid in the syringe I compressed pure fluid back into the brake, just as they showed on the youtube vids. I repeated that process probably 7 times, and yet air always came out of the system. I was even tapping on the lever, brake line, etc. the whole time to try to free the air. Then I noticed (while compressing fluid back into the system) I could hear a slight hissing/sputtering coming from somewhere in the lever. Yet, no fluid leaks out, ANYWHERE. I suspect that's where the air is getting in. Why does it let air into the system yet not LEAK???

Is there anything I can do about this or is my brake jacked?

 

[maxyedor]

How tight are the hoses on the bleed fittings. I can't hardly pull a vaccum on any of my bleed kits as they just burp on the fittings. I'd say that's the more likely culprit, though a leaky lever isn't totally out of the question, just unlikely given the symptoms you described.

Try pulling the plug on the lever, and pushing fluid through from the caliper side, once it starts over-flowing, suck it back, and repeat a bunch of times until the bubbles stop. Then push a ton of fluid through to flood the lever really well, cap it, and clean up the excess DOT ASAP. That's how I've always done brakes, and it always seems to work.

 

[kail]

^^Well, that's the problem (or one of the problems, anyway) -- I can't get any fluid to go from the caliper to the lever, it feels like there's a valve closed or something. However, pushing fluid into the caliper does move the pistons.

The bleed fittings seem good; no problem at all getting a vacuum. The sound when I compress the lever side syringe (caliper side plugged) is coming from inside the lever housing. Yet...no fluid leaks anywhere.

 

[maxyedor]

Ok, wasn't sure if you couldn't push fluid through at all, or just couldn't push the upper syringe with the lower.

The hissing could just be air or fluid moving within the MC. I can't see there being a blockage, since they do work. To double check for a blockage, take the hose off, and test each components to make sure they're flowing individually.

Beyond that, I'm a bit stumped.

Last resort you can bleed them like your car brakes, pump 5x, and check the fitting. It's a total PITA, but I've done it when I don't have a bleed kit handy and it works.

 

[kail]

For anybody interested, I took it to the shop where I bought it and they were just as stumped as me. But then they called SRAM and found out that if your reach adjustment is too far in, it won't take a bleed. After adjusting the reach the other way, it took a bleed just fine, lol. Brake worked awesome during my first enduro race on Saturday! Too bad one of the stages was "XC" downhill...at best. Hell, I would call it just plain XC. I was doing great up until that point...then I was regretting not having an XC hardtail.

Somebody needs to set up an "enduro" race that has 4000+ feet of climbing followed by a world-cup level DH all the way to the bottom...sigh.