Looking for a bit of help please. I’ve still got brake squeal on both front and rear brakes after months of trying to fix it. This is supposed to be my reliable bike! The squeal is a high frequency, and if I am light on the brakes and push the bike I can set up a really strong resonance in the whole wheel, where the pads grip and release the rotor allowing a rotational stop start motion.

The item’s I’ve changed are as follows:

– Pads (Shimano Resin to SS Organics)
– Rotors (Avid G2 to SLX, checked torque on both)
– Torqued all caliper mounts
– Centralised Caliper (many many times – visually perfectly aligned).
– Different forks / tightened topcap + stem
– Different frame (swapped brakes over between bikes)
– Wheelset (Alex rims swapped to flow rims, both shimano hubs)
– Bleed
– IPA’d and sanded rotors
– Coppa slip back of pads
– Pushed pistons out and lubed (made it less sticky by hand, but no lever feel difference)

I think that’s everything, and they still squeal front and rear. The levers feel nice and strong, and with the shimano pads the brakes still stop me adequately, but honk incredibly loudly. SS pads are not fully bedded in yet, but I can’t bed them in with the horrendous vibrations and noise present. The brakeset are 18 months old.

I’ve searched the forum history, can’t find anything else. From the above the only common component is the caliper – what else can it be? If I get new calipers, that’s £50 in total, and the brakeset were only £90, so it’s hardly worth it.

A bottle of my finest homebrew is offered to the supersleuth that works it out, because it’s beyond me now!

simultaneously change both rotors and pads

(or at least, clean the rotors + fit new pads)

oh, have you changed the calliper adaptors yet?

Face the disk mounts? Wrong adapter?

These are guesses BTW, you’ve done a lot more than I would have done before binning them! 🙂

I haven’t changed the caliper adapters except where I needed to changing between a particular set of forks.

As for facing the disc mounts, I’m under the impression that would only be effective if the caliper was not presented to the rotor square and true.

The rotor’s have been cleaned before the new pads were added. Shimano pads were sanded prior to trying again as they’ve been used before. SS pads were just whacked in as new, as well as cleaning the rotors.

I’ve come close to binning them but finding it hard to when so many have success stories with this brakeset – hence buying them!

I had XT brakes of similar vintage and couldn’t stop front squealing or having zero stopping power, eventually discovered it was leaking fluid into the pads.
Take your pads out and make sure they are clean and dry, rebuild then elastic band your brake on overnight, remove pads and see if they are still dry.

My best remaining guess is that somewhere along the way, the part of the calliper that keeps the pads in place has become worn – possibly from vibration in the first place (the cause of which you may very well have fixed) – and as a result it now has enough slack to allow any pad to judder/vibrate.

Sell them, life’s too short 🙂

(Avids FTW)

I’ll try the rubber band idea as a test. I’ve not observed any oil so far and pads have never appeared contaminated. It’s certainly worth a shot to either rule it in or out.

The pads are certainly able to float in the calliper with the rotation of the rotor back and forth, at a guess 0.5mm or so. I did shim this at one point to remove any play but it made no difference. Also theres no paint missing on the contact surface so it looks like design intent in order to allow clearance for the pass to move within the calliper body.

I’ve a pair of juicy 5s which were second hand 4 years ago. No issues with them really!

Pads init, if I use cheap pads they scream like ****. Shimano ones are silent.

Thanks for your input banks. Unfortunately as described up above the issue began with Shimano pads. I’d welcome any other ideas you may have that haven’t been covered above though?

Can I suggest putting a slight chamfer on the thin edge of the pad friction material?

same brakes same problem. Tried everything as you did, but yesterday I cable tied lever down for 20 mins and there was an obvious dribble of oil from the pistons. Am I right in saying shimano do a 2 year warranty? sending mine back to crc soon as I get chance

Well, this evening I cleaned pads again, swapped rotors, pads, chamfered pads, no difference.

The levers are ty-rap’d to the bars. I’m sure you’ll all be eagerly awaiting an update, so I’ll post up the results first thing in the morning. Hopefully there will be a conclusive leak from somewhere, whether it’s me not tightening up a bleed nipple or hose union (I’ve checked for tightness), or leaking past the seals.

I have some m596’s and use shimano pads with rt76 rotors. Changed my rear pads recently and its taken a month to bed them in. Took a very long steep path to finally sort the squeal out.

Also in the past had to take rotors off and boil them to get rid of contamination.

You use old socks for rotors?!

I had some of the M596 brakes that we’re bit noisey. I set about the brake pad linings with a blowtorch to burn off any crap that was contaminating them then cleaned the pads with emery cloth.
It seemed to do the trick.

Shimano brakes are rubbish, they spray the oil onto the pads / rotors when the seals go, and then the pads are toast and you have to buy new calipers. I have been through it, believe me (search old posts). Wouldn’t touch Shimano brakes with a bargepole now. Get Hopes.

Seriously i have the same problem. Stop cleaning everything – stick some shimano SS pads in a drag ’em down a big ass hill.

Couple of things this morning which point towards a seal failure. Slight moisture visible around the seals on the front calliper only. May have affected the rear due to the amount I’ve been troubleshooting and swapping parts around. Also telling is the levers lost a bit of hardness, indicating pressure loss I.e. loss of fluid. Did exactly the same on the avids to compare and they maintained pressure.

Looks like front calliper seal them, but I’ll leave it longer to confirm.

Banks, this conversation is being taken seriously I can assure you. What are Shimano “SS” pads? Where I’ve used SS before I’ve been referring to super star components pads.

Shimano sintered sorry. Tried a few, clarks were the worst, last ages but squeal so bad.

Where about do you ride, is it peaty/greasy conditions?

.. this is another longshot idea. I’ve had similar-sounding problems with my XTRs.

The brakes were originally ‘serviced’ by my LBS, then the problems began. On the next ride I had both brake lines come lose at the calliper end – resulting in a loss of fluid and brake function. Whether this was my LBS’s fault – due to inadequate tightening of the banjo-end or some design fault with the callipers is open to debate.

Anyhoo… after the failure they ‘re-serviced’ the brakes and fitted new pads – at my further expense and – I believe – failed to adequately clean the callipers of the oily residue that remained from the original failure. Only after a dry dusty ride recently could I see this film of oil that remained. Although the brakes have worked fine since, I think over time, a small amount of this residual fluid mess has migrated onto the pads. Resulting in squealing and fade. If the pistons were leaking oil – the residue would also be on the metal back of the pads – which is about the only place I can’t find oil.

I’ve since taken the callipers off the bike and removed the pads and given EVERYTHING a thorough clean with paper towels and methylated spirit. The problem appears to have been sorted – very nearly squeak-free apart from the first 5 minutes of a ride. I think a small residual ‘glaze’ of burnt oil remains on the pads/rotors which I will have to sand off. This is my theory anyways.. 😉

My point is – with all this faffing about you have endured with these brakes, perhaps there may be a small film of oil remaining on the callipers that needs cleaning off thoroughly?

Have had an ongoing situation like this with some older XT’s and some new Deore 596’s this year.

I don’t entirely disgagree with the serial Shimano Hater above and the fine oil mist on leaking piston seals but you can check for that.

I went through the same rignoral of cleaning rotors, swapping pads and mounts etc. to try and find the route cause. I don’t think I really did but as the brakes never faded even when howling like pigs (and it was only the rear ones) figured there wasn’t oil loss.

In addition, when I fitted the Shimano A01S pads (halfway house between sintered and organinic) the brakes became silent and remained so.

In the end it looked to be some glazed up or contaminated pads (Shimano sintered) that just went wrong. Uberbike sintered also seem to heat up easily and squeal. So it’s back to Shimano sintered and maybe a bigger rear rotor as the 160mm on both set ups has discoloured that bronzy tinge from overheating.

Also agree with NED above as worth doing.

Thanks no-eyed-deer. That’s something I did suspect, and any oil remnants would have invalidated my ‘leave it over night’ test, so thats what part of the last night clean up was – thoroughly degreasing the caliper, removing coppa slip, and anything else around the pistons from lubing the pistons/seals the other day.

If there’s oil coming out of the pistons it should be pretty obvious now, and also it will always recontaminate clean rotors or new pads, causing the problem to rear it’s ugly face again after a short period. If there’s no oil coming out, and the problem doesn’t recurr, then you may well have hit the nail on the head.

If the seals are gone, they’ve failed with normal useage conditions, and probably only done 700 miles or so, in 18 months. That’ll be warranty job then (shimano does a 2 year warranty), as that’s not really good enough, especially given the reliability of supposedly poor Avids!

As for the area ridden, it’s currently the chilterns ish. So clayish mud.

Same here- had an XT that leaked at the piston seal after a year or so, replaced the caliper this spring with a 596 and now it too is leaking very slightly after being excellent at first. Best send it back to supplier, I think. That’s where mine is heading.