[Closed] Here's one for you! Even bike shop can't solve!

Check frame brake mounts (if not already done, they should have done it)

it's possible I once came near to them, every brake I've ever touched instantly becomes irrepairably squeaky. The only solution for me is to not care 😆

Is Sweep trapped in the rear triangle?

Ear plugs?

Youve got contaminated fingers

I would suggest you reface the brake mounts on the frame using the correct tool, this may help

Frame is obviously possessed by a pig. have you tried holy water?

Have you bedded in the brakes properly or just ridden round the block?

Have you tried magic water?

Is this all the time, or just when applied?

Have you tried a different brake?

Tiny bit of Copper grease on the back of the pads and between all shims if you have them and also on all threads

Swap to shimano rotors. Problem solved.

What carlos said.

Is Sweep trapped in the rear triangle?

😆

Although I'm still annoyed I expected replies like this and they making me smile... But I'd really like to enjoy my new bike without annoying everyone I ride with!

The rear calliper bolts straight into the frame on the Anthem.

Pour coca cola over disks and leave for a while then ride, accelerate and brake hard then repeat, while singing the coca cola song.

You may wish to ignore the singing part.

+1 for having the disc mount re faced.

Out of interest how do you align your pads?

Tried complete new SLX kit including pads, wheel and rotor!

If the rear mount is miss assigned a new brake will make no difference.

Out of interest how do you align your pads?

Just to split a hair: it's the caliper that one aligns, not the pads. Pardon me if that's what you meant.

Hope video does a good job of describing caliper alignment...

I adjust my calliper to align my pads if youre being that picky.

+1 for facing the mounts.

Have you checked the rubber hub bearing seal? Mine was dry and squealed like a pig, a small smearing of grease sorted it.

I've had this on my slx brakes - after a lot of fannying around it turns out they're very sensitive to alignment. I spent ages aligning them and they no longer squeal.

Rubber hub bearing seal?

Apologies but I'm new to all this!

I'm not sure how to adjust the mounting bracket as the calliper is bolted to the frame?

As for the coca cola.... My mate suggested the same thing! Can of coke at the ready!

Ill try post a pic of the calliper.

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Stop giving a shizz, problem solved. Or GT85 straight on th disc.

Swap from organic to sintered or vice versa? I had a real problem on one bike with sintered. Made a nose like an angry goose. Semi organic/ kevlar made it only happen in the wet. Oh and swingarm bearings checked or replaced?.

Cheers for the video post. Will try that now.

What avid rotor is it thre was a bunch of stuff about avid rotors and resonance not that long ago which avid responded to by re-doing the rotor with less groves.

Maybe the Shimano brakes are having the same issue as the elixirs had in the past?

Edit, just seen your pic with a roundagun rotor, don't think they were the affected ones, however cross brands may yield the same issue.

How is your pad wear with that rotor, it looks kinda low against the caliper?

The bike shop changed everything!

Even borrowed a wheel!

Ill take pics of rotor and pads....

Conversely my slx set up with XT discs it's pretty quiet, bar in the wet.

Avid says A17 JUN 11 160MM HS1

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Pads say Shimano L F296 R F294
Both F03C METAL

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I would say check everything is tight, calliper bolts, rotor bolts, QR - and make sure all threads are lightly greased.
and if your lbs can face the post mount get that done as noise comes from vibration and if its not square then the pads wont be making great contact.

Are the post mount bolts the right length? I recently replaced a friends brakes and the mounting bolts were minusculely (not noticeably) longer than they needed and the brake squealed when tested. Took a while to work out as the bolt did up tightly and it looked like a snug fit.

Finally tracked it down to the bolt length, filed a couple of mm off the bottom and problem solved.

Although I doubt very much it'd work, it's cheap and quick to try:

how about some washers made from an old inner tube in the mounting bolt "stack" above & below the caliper - might just dampen any vibrations ?

This is the weird thing, the PO has been fantastic and is helping as we go...

He rode it in October and no squeal at all.

It then stood till last week when I bought it. The PO had it tightly packed in his boot with both wheels and saddles off. When he put the bike together and I rode around the rear brake squealed like crazy and WOULDN'T stop me. I could pedal through the tightest of pulls. Thinking it just needed bleeding I took it to my bike shop and all this happened! Lol.

The power is there now, but not like the front. The front is amazing!

Confused.com!

Get Sue to have a look at it for you

1)has it only ever had the mismatched brake/rotor? Or have you tried a Shimano rotor with it?

2) some time spent making sure the 2 pistons are pushing evenly is worthwhile. I've had Shimano brakes centred by the usual method, where they're actually working more like a cable brake - with one pad pushing the rotor over into the other. Holding back the enthusiastic piston to let the other work its way out sorts this.

CHANGE THE ROTOR TO SHIMANO! !

Check the hose isn't resonating. Never had it myself but read about it happening to a specialized full bouncer in a mag, may have been MBR. Sounded a bit odd to me but you could try adding some zip ties to the hose to ensure it's secure. Seems like you've tried everything else.

That being said you say the rotor was changed but that's not a shimano rotor in the pic, this seems to be causing some confusion.

I'm sure the rota was changed to a shimano but I shall ask the shop tomorrow!

that'd certainly be number 1 to check!

Had a similar thing with a Deore brake. I ended up changing for different brakes (on this occasion Hope) and the problem disappeared. The Deore one would squeal and send a horrible vibration through the frame.

Fit a Avid brake , it won't work well for long enough to squeal...problem solved.

To rule out pad rotor miss match can you borrow another brake and disk that is known not to squeal from another bike and try it on yours?

I know you have suggested this was tried already however I have not known squealing to come from anything but a brake. Creaks can come from lots of different things but not normally squeals.

Yes cheers that's the next step. The bike shop is going to bring one in that is known to work and try it on my bike. The sound is definitely coming from the brake but is echoing through the frame!

I've followed the vid and set it up.

Still squeals.

I shall try the coke tomorrow and go for a good ride and see how it goes!

Cheers for all the constructive and funny replies.

Sooty.

ask the shop to check the dropout alignment and face the brake mount while you are there.
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pads and disk look a bit glazed in the photo, take care not to get chainlube or cleaning products on them.

from those pictures it looks like the discs and pads are glazed right up.. get the pads sanded on some rough sandpaper and rub the discs too, but on sandpaper not as rough. get that burnt crap off.

I'd agree those pads look glazed and filthy, sounds to me you needed new pads and maybe the rotor is covered in oil, wd40 or whatever. So you go to lbs, who fit new pads on a filthy rotor, probably sintered pads so they squeal and also get contaminated. Sounds like you need to try a different lbs, or just buy some pads and a new rotor yourself. Try a different compound as well sintered pads seems to always be a bit noisey

Humm, I did think that about the contamination being exchanged!

So what grade paper would you suggest? Again doing a quick search brings up loads of answers!

Cheers.

I had big problems with brake judder on the rear of my Stumpjumper with the same rotor

Swapped it to a standard round one, problem solved

Sooty, I have seen this dozens of times now with Shimano calipers. Including my own. Not just slx but at least 3 different types. My old slx have been on the bike from new and after it laying around in the shed (cold seals) it would howl on the first ride. Another thing I noticed after changing the pads a few times was that fine dust would show up on the caliper on what seems to be like a vapour of brake fluid.

It still does it to this day and I never bothered sending it back. I should have but I have been getting by with braking it off on the first descent or splashing a bit of mud on the rotor. It's not the answer but on an old brake on my 2nd bike, it does the job and the bite returns.

Over the past year or so I've noticed dozens and dozens of shimano calipers now coming with a sealant that never gets thoroughly cleaned off during assembly. It's a light grey colour and often found smeared around the centre of the caliper halves. I worry that this has been their attempt to try and cure a problem. The reason being, dozens and dozens of brakes over the past year (at least a year) have been assembled, and have suffered from the dreaded 'leave your bike stationary for a week - come back to a disc and caliper that becomes contaminated without even touching it' It's not soaking,and it's not dripping. The calipers just develop a light dampness that's noticed by the unusual dust build up.

I am pretty sure that if you removed the brake and fitted something else, after cleaning the rotor thoroughly or replacing it, you will find the problem.

How good is the performance? Is it easy to lock up the wheel and come to a stop or do you just slow down - with a terrible shriek/noise throughout the whole braking attempt?

+1 on the glazed pads.

Something not right there, they're shiny with what looks like uneven wear across the surface.

Copper grease on the back of the pads is the answer, usually.

Check the hose isn't resonating. Never had it myself but read about it happening to a specialized full bouncer in a mag, may have been MBR. Sounded a bit odd to me but you could try adding some zip ties to the hose to ensure it's secure. Seems like you've tried everything else.

This. I had this on my Specialized FSR, cable tying the brake hose to the frame solved the issue. About 4 weeks later MBR had the same issue on their longtermer, I tweeted them what worked for me and it solved their problem too.

It then stood till last week when I bought it. The PO had it tightly packed in his boot with both wheels and saddles off. When he put the bike together and I rode around [b]the rear brake squealed like crazy and WOULDN'T stop me. I could pedal through the tightest of pulls.[/b] Thinking it just needed bleeding I took it to my bike shop and all this happened! Lol.

Important bit in bold.

Definitely points to contamination of the braking surfaces.

Go to your local motor factors & buy some brake cleaner (half the price of bike branded stuff).
Remove rear wheel and liberally spray cleaner around rotor then wipe off with a clean cloth/j cloth.
Remove pads and using a rough sand paper on a very flat surface (pane of glass is ideal), scuff the pad surface until it's no longer glazed.
Whilst pads are out visually check on pistons, seals etc for signs of a leak.
Put it all back and try that.

My Saints squeal if left for any significant amount of time. The remedy is just ride the thing hard for a few miles or throw some water over the brakes and rotors and ride up and down the road with the brakes applied slightly. This should get rid of most small contaminants and will face the pads a bit. It's not foolproof but I find it works most of the time. If it doesn't I just ride it until it doesn't squeak any more. Mine's on Super* Kevlars though so not directly comparable.

Good luck with it there's few things more annoying than a squeeky brake.

On a serious note it may be worth giving the bike a good clean and having a really good look for hairline cracks thus allowing it to flex more than desired when braking.

You say the brake has been replaced yet the noise continues and has been tried with different wheel, rotor etc, the only other constant is the frame so thats where I'd be looking.

Had a similar problem on a Merida frame. With a Hayes brake on that frame it squeeled like a demon. Tried lots of different combinations of rotors, brakes, frames, pads and all solutions including facing the disc tabs. In the end it was simply that particular frame and caliper wouldn't play nicely.

Same brake on any other frame, fine. Same frame with any other brake, fine. Just not together!

Some things are just a mystery!

I have similar issues with my Trance X and rear SLX brake - vibration/judder before brake bites. It doesn't affect the breaking perfomance though and soon disappears once I'm into the ride. I think martinxyz's comments about brake seals is relevant to mine - I don't get out on my bike much.

+1 shimano rotor and clean pads.

-dump the Avid rotor and buy a Shimano rotor (they have a different braking track)

-dump the current brake pads, and buy some new brake pads (your old pads are dirty, and may be contaminated)

-degrease the caliper bay with disc brake cleaner or iso alcohol before installing the new pads

-reset the pistons in the caliper using a 10mm ring spanner, push them fully home

-install the new pads

-centre the caliper over the middle of the rotor, tighten the caliper bolts. give the brake lever a squeeze, check the contact between pads and rotor, should be even

-find a new local bike shop!

*certain bike frame and brake models / pad types* have a known resonance problem, but its not something common on your Giant, so its probably bad setup ~(the Avid rotor does not help..) or contamination

**Put some copper grease on the back of the pads**

Not the front obviously - although that would probably also stop the squealing.

Ok, development!

Poured coke over the calliper and discs and after 10 mins went for a ride.... Still squealing like mad.

So then I spent ages cleaning with brake cleaner and went out for a ride... Still squealing like mad.

So pads and rotor off, fine sand all over to fresh material and went for a ride... Still squealing like mad.

As I was swearing and putting my bike in the bin I wondered if the pads were the same on the front.... So took front and rears out, checked, yep the same. So put the front in the rears and rears in the front. Spun the wheel at the rear and NO noise at all. In fact the brake was amazing! So spun the front ( previously excellent ) and yep... Squealing like mad!!!

So now I'm over the moon but furious!

So I called my LBS back up and spoke to the mechanic about exactly what he had done and he had tried two new sets of pads in the rear but still squealed. Can this happen????

Confused and bewildered I accepted the fact I'd spent money trying to solve the problem and like most have said... PADS!

So now I feel an idiot and have to praise the PO for bring so understanding and generous in offering to meet me and try resolve it with his brakes or give me my money back! Now that from a seller is honesty as he promised the bike was fine.

So I'm very happy, I love the Anthem, but pretty annoyed that such a simple thing wasn't fixed first, but such is life!

Thanks to all who commented, constructive and funny!

Now to call the PO and tell him the good news!

Should I buy the pads mentioned in a previous post? I'm not buying Shimano!

Cheers, Sooty.

I'm not buying Shimano!

Why not? They're great, a bit pricey but great.

I'd avoid Super* Kevlar if you're worried about the squeeking as, as I said before, mine do it when they've been sat for a while.

I had an old (M486) set of Shimano Deore brakes fitted to a 2nd hand bike i bought for commuting, they had the same problem.
Turns out that there was a small amount of brake fluid leaking from the piston seal onto the pads/rotor causing them to sequel and a lack of stopping power. New pads solved this initially but after a little riding the same would happen again. Check the caliper pistons for sighs of fluid.

I got it. Mine were doing this till yesterday, 're-aligned, changed pad, shimano Rota. nothing.
The problem, even when completly retracting the pistons back the brake rubs the disc on one side, they do not meet evenly.
I lossened off the caliper bolts and placed a thick cable tie between the pad and the disk on the side that rubs, pull the brake lever, tighten the caliper bolts and remove the cable tie. It now doesn't rub anymore. Doesn't change the fact that the calipers don't squeeze evenly.