Bleeding avid brakes

antfly · January 2010

Hi, my brakes were rubbing very badly especially on the front so I bit the bullet and bought the overpriced bleed kit and bled them just now. Anyway, they are still rubbing the same as soon as I squeeze the lever a few times. I have put a bit of the oil on the pistons which were sticking a bit and seem to be moving ok now, it hasn`t helped so is there anything else to try before I bin them and get some other brakes? I don`t really want to be spending much more time and money on them. Ta.

nicklouse · January 2010

set them up correctly.

what type of rubbing is it?
constant one side?
constant both sides?
intermittent?

antfly · January 2010

The wheel hardly turns at all, that kind of rubbing.

bails87 · January 2010

Too much fluid?

antfly · January 2010

No, the pistons go in all the way easily when I push them.

Kanya · January 2010

My Avid Elixir R's were exactly the same issue, pissssed about with them for ages. They were rubbing on both sides, now I've had wheel off, pistons put back in place, business card trick yadda yadda...its still rubbing on one side.

Figured it's a bleed issue (theyve bedded in for sure), and figured as I have a years (free) Halfords servicing voucher, they can sort it. Which is actually where it will be going in just over an hours time.

Thankfully, the guys in that branch seem to know what theyre doing. That said, when I pick it up again, I will be asking exactly how they fixed the problem (if its not related to bleeding)

Been trying to sort the same prob for a few nights now, so feel your pain and annoyance.

bails87 · January 2010

Maybe take the pads out, squeeze the lever to push the piston a little further out and make sure they're clean lower down.

That's a solution I've just made up btw, not official or guaranteed 'safe', it's what I'd do though, just as long as you've got enough room to push the pistons back.

antfly · January 2010

Kanya wrote:

My Avid Elixir R's were exactly the same issue, pissssed about with them for ages. They were rubbing on both sides, now I've had wheel off, pistons put back in place, business card trick yadda yadda...its still rubbing on one side.

Figured it's a bleed issue (theyve bedded in for sure), and figured as I have a years (free) Halfords servicing voucher, they can sort it. Which is actually where it will be going in just over an hours time.

Thankfully, the guys in that branch seem to know what theyre doing. That said, when I pick it up again, I will be asking exactly how they fixed the problem (if its not related to bleeding)

Been trying to sort the same prob for a few nights now, so feel your pain and annoyance.

It`s certainly a pain. If the good people at Halfords manage to fix it and they tell you how please could you let me know.
Bails, i`ve tried all that, more than once.

konadawg · January 2010

If you don't mind getting dirty- Split the callipers, pop the pistons and clean them out, and also the callipers bore. And replace the piston seals. The "return" for the pistons is usually based on nothing more than flex in the piston seals so if these are stiffening up/have taken a set/ pistons/callipers dirty, stuff won't work the way it should, resulting the the pistons staying "out".

It happens!!

frogstomp · January 2010

I had a similar problem with my Elixir R's.. one of the pistons wasn't returning correctly when you released the brake lever.

To fix it I:

1. took the pads out
2. clamped the piston that was working correctly
3. pumped the brakes a bit to expose the 'bad' piston (not too far or you'll let air in)
4. smeared a bit of brake fluid around the sides of the piston
5. pushed it back home into the caliper
6. repeated steps 3 - 6 until I operated more smoothly..

antfly · January 2010

Tried that frogstomp.

konadawg · January 2010

I'll not repeat what I posted before which is the next step and which should fix them, but before that check your lever adjustments, do you have any free play before the brakes "bite"?

If not you may have over adjusted the lever outwards maybe?

If not just replace the piston seals and clean everything up, there is no-where much else to look at, but if you don't want to do that and fix them then buy new brakes - there is no alternative "look at the moon and chant this mantra 3 times" that anyone can offer to fix it.

antfly · January 2010

Thanks for the advice, i`m sure you`re right konadawg.
What happens to the brake fluid when you split the calipers, does it just pour out or what?

joshtp · January 2010

when you bled them, did you make sure the lever reach was adjusted s in at least a bit? i would try bleeding them again with the lever reach wound in.....
and whatever happens, dont just chuck them in the bin, it makes me cringe to hear of people throwing stuff away, ir you dont want them, ill have them, and try what you can, im sure they will be fixable....

bluechargeboy · January 2010

If you split the caliper there will be a small amount of fluid loss from the caliper body, but you won't lose a lot (unless you have the bleed port at the lever open probably). FWIW when I split the caliper I used scotchbrite to make sure the piston was smooth (too cheap to buy new ones).

After doing this my brakes were still rubbing, but I cured this problem by making sure the caliper was lined up perfectly on the disk, otherwise one of the pistons needs to come out a long way to contact the disk, and seemed to stay out and rub the disk.

It's very satisfying watching the wheel spin freely once you get it sorted!

antfly · January 2010

joshtp/mbukman wrote:

when you bled them, did you make sure the lever reach was adjusted s in at least a bit? i would try bleeding them again with the lever reach wound in.....
and whatever happens, dont just chuck them in the bin, it makes me cringe to hear of people throwing stuff away, ir you dont want them, ill have them, and try what you can, im sure they will be fixable....

I tried bleeding them again .They did come on the bike which is 3 and 1/2 years old and the rear one has always leaked at the resevoir and looks a mess. They always rubbed with new pads and then they rub when the pads are old and sometimes squeal like a stuck pig and need constant adjusting. TBH I wish I had v-brakes on my bike.When i`ve got a new brake i`ll take the damn thing apart properly before I bin it but I can`t be without my bike.

Bluecharge, I think I would need new seals, I had a look and it looks like you can only buy a whole kit for £28, add that to the £34 for the bleed kit and I could have bought a new brake so it`s time to cut my losses.

bluechargeboy · January 2010

Piston/seal kit is called "Avid Juicy pressure foot kit" (assuming they are Juicys) and can be had for around a tenner I believe. TBH I have been close to getting rid of my 6 month old Juicy 4s but they have had a reprieve after I got the pistons moving then bled and aligned them. I think they maybe need a lot of care and feeding though....

antfly · January 2010

Oh yeah, who would have thought it would be called that?
Now i`ve got no excuse.

joshtp · January 2010

personaly i hate avids! the new elexirs have great power and feel, but they are pigs to maintain, and the juicys dont even feel very nice, and they arnt very powerful. the fact that J3's are often ofered as an option as un upgrade makes me laugh, my old tektro auriga's are by far the best brake iv ever used, and iv tried everything from strokers to m4's.....

gustie · January 2010

i have juicy 3's

ive seen 2 methods of bleeding

1 - with the pistons totally wedged in as much as possible with no pads in

2 - with wheel on the bike, pads fitted and relying on the disk to space out the pads/pistons

i used a red racing bleed kit for £17 - seemed to do the job ok - but could do with a longer syringe for vacuum pulling the air bubbles out of the brake lever but apart from that worked ok..

I tested it round cwmcarn and lived to tell the tale, although out of curiosity i repulled the lever with syringe and managed to get more bubbles out -

i used method 1 above - farted around with the 2 bolts that held the caliper on until it didnt rub and its all good now.

another thing to note possibly is that the piston seal is square edged and may have twisted around making the piston sticky and not moving properly? i pumped mine in and got the old blocks in there and twisted a flat head screw driver between them to make the piston go totally back, cleaning round the piston a few times, just for good measure, maybe if your piston seal has twisted then this might help... mine are not rubbing now - i guess until i grit them up again!

antfly · January 2010

OK so I bought a new front brake and fitted it in about half an hour and bled the rear after I had put the old front lever on it as it was in much better condition. So far so good, just a bit of rubbing at the back, then today the rear is sticking just as bad as the front one and also the fluid had leaked out at the lever when I turned the bike upside down.I re-bled it but it was stll sticking so I split the caliper but couldn`t get the pistons off . I don`t know what adapter you need but my pump kept shooting off. Anyway i`ve come to the conclusion that avid juicys have a natural lifespan of 3.5 years and also that it is a lot easier buying new stuff than trying to repair crappy old stuff.

antfly · February 2010

Well I stuck at it and managed to get one piston out and it was hard work but on the other one you have to cover the hole with your finger as you pump according to the sram manual. Yeah, like that`s going to work considering the presssure it took to get the other one out, I think sram must be having a laugh when they wrote that. More time wasted. I really should take my own advice.

mmacavity · February 2010

Are you wearing the right shorts?

http://www.youtube.com/watch?v=6mg6NbIjmOM

ride_whenever · February 2010

Last time i saw a piston out of a juicy the mechanic sent had it at 180psi...

It FLEW across the workshop! But they didn't stick after the re-build!

Buy hopes or magura instead, a child could bleed them.

antfly · February 2010

That HB guy is funny. I must have watched that 20 times now but I never noticed the cool shorts before.

I`m quite good at bleeding them now cos i`ve done it so many times since I got the kit, but changing the pistons clearly isn`t a job for the average punter in their garage. How can you stop that kind of pressure with your finger, it`s just silly? You could kill an innocent bystander if it ever does come flying out.

Bleeding avid brakes

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