Avid Juicy 5 front brake emits a constant high pitched drone

d60eba

Hi,

First apologies for my rubbish bike knowledge. I'm a complete newb. I took my Felt Six Comp with Avid Juicy 5 brakes in to be serviced. Now, having just taken it out for a quick ride, the front brake emits a constant high pitched squeal/drone. Some details:

- At first it only did it at high speed, but by the end of the ride it was at any speed
- Tapping the bake stops it for a while
- Holding down the brake just a fraction, not even enough to notice the difference when pedalling, stops it (but then when you release the brake it'll come back after a while)
- Slamming on the front brake will stop it for a minute or so, but then it comes back
- Locking the front suspension improves matters, but it'll still start doing it after a (longer) while

I'm going to phone the place that did the service and ask them what they've done, but I'd like to be forearmed with some knowledge about what's causing the problem. I did some research on the forum and found some similar problems, but not with the exact symptoms.

Any advice on what's going on here greatly appreciated!

Thanks,

Leon

nicklouse

the pads need to bed back in again.

but first remove and refit the front wheel making sure it is fully seated correctly.

konadawg

Or possibly the calliper was not centred correctly, look up the procedure easy enough for anyone.

pugaltitude

Iv got the same noise from my avid 3 brakes.
Iv noticed that my front wheel isnt turning round freely and is sticking because of the brakes which could mean i have a warped disc or like nicklouse says it could be the pads.
I was also going to try copper ease on the back of the pad which might stop the squeak assuming its ok to use?

ride_whenever

don't copaslip the pads, check the disc for warp and realign the caliper, it isn't hard and far more sensible than copaslip.

diy

Unlikely to be a warped disc, just need to reset the calliper by easing the pads with a tyre lever or similar to push the pistons back in, then reset the alignment.

If its still doing it, repeat, but remove the pads and give the brake a squirt of some quality brake cleaner or alcahol based cleaner. Avoid anything oil based.

robv1306

I have this problem all the time when building bikes for customers, as most of the manufacturers I deal with spec them as standard.

The problem with avids in general is that they run STUPIDLY close to the rotor in comparison with hope or shimano, which can be set up by a blind monkey. Avids require a deft touch and LOTS of patience.

The problem generally tends to stem from either the pistons not being pushed back all the way, (very common for less experienced mechanics to miss, as they are SH*T scared of cracking the pistons), or it simply not being correctly centered as theyre working to a time limit. Try pushing back and re-centering accurately.

If this still does not work, take out the pads and wheel, detach the caliper and push the pads all the way back again. Then, being careful not to push them out past the seal, slowly compress the lever so they move out from their stops. They should both come out at the same rate and not jump or stay still. If they do seem jumpy on the way out, you may have damaged pistons (making them "sticky") or they may just require a liberal cleaning. Pray its the second as the first tends to be fatal for the brake as pistons are a b*tch to change on juicys.

Best of luck dude! . Hope it helps!

d60eba

Thanks guys for all the replies.

Here's what I've done. I took off the front wheel using the quick release system. Then I got a flat head screwdriver, wedged it in between the brake pads and wiggled it left and right until the brake pads were back as far as possible. (I assume this is pushing the pistons back, but I didn't see any pistons so I can't be sure.) Then I put back in the front wheel. The rotor, however, isn't centered between the brake pads so when turning the wheel it rubs against the outer pad slightly. So, I imagine this is what "centering the caliper" will fix. But to center the caliper it looks like I need an allen key - so I'll report back once I've gotten hold of one the right size.

Incidentally, the rear wheel (which doesn't make a noise and I thought was OK) rubs on both sides of the pad without braking. If I give it a good spin it comes to a complete stop by itself after about 3 seconds, which seems ridiculously quick. So I guess I'll need to push back and center on this one too.

Thanks,

Leon

robv1306

Yeah thats exactly what you need.

As i mentioned before, avids run ridiculously close to the rotor, making them a bitch to set up. In order to push the pistons back though, you need to remove the pads and use a small ring ended spanner, to CAREFULLY push the pistons back (you will see them once the pads are out). Doing it with a spanner will cause damage to your pads.

To be honest though, if youve recently taken it into a bike shop and its come back to you like that, take it back and tell them to push the pistons all the way back in and center both brakes properly. Sounds like theyve done a pretty shoddy job. As i mentioned before, it just takes patience!!