I’ve some old model Deores.

They have been gutless for a month of so, now squeal like a pig with its knackers caught on barbed wire.

So far I have:

– cleaned pads and discs with muc-off by tooth brush.

– sanded pads and discs

No change.

– changed pads for new Shimano’s I had in the toolbox.

MORE squealing, less bite.

Even worse. Now discs and pads are coated in noticeable black brake dust / feel slippery to finger.

Suggestions as I am about to chuck on some new pads – could I have cooked discs? Maybe leaky pistons? Sintered Shimano are sh*t?

They are under warranty, but I am dreading Rutland’s lack of interest…

@Mods – should this be a sticky thread?

To match the leaky calipers?

I’ve had this happen with a couple of different shimano brakes, usually the rear, I’m not sure what it is but I don’t think there’s a fix.

^thats what I suspected. I have tried *everything* – had given up on some 5-6 year old ones that did this, but wondered if there is a new ‘fix’.

Time to see if Rutland will warranty…

Gt85 should sort it

New rotors.

Ive had similar problem and new rotor fixed it.

Make sure u bed it in properly. Or it will glaze and squeal.

I had the same problem and the fix was to ditch the sintered for resin…..been ok since.

Could be leaking pistons in the caliper:

https://singletrackworld.com/forum/topic/help-my-brakes/

ime with shimano brakes is once the squeal sets in you need new rotors and pads. i had it once and i tried everything including dishwashering the disks.  i think the disk gets contaminated which contaminates the pads. never use a second-hand pad on a new disk.

Aye new pads and rotors. Worked for me anyhow. Think they just get to a point when they are unrecoverable. Particularly when the rotors looks discoloured.

Sounds like the leaking caliper/piston seal to me. Only option is to return them and get a replacement.I’ve had this happen to at least two sets of Deores now. When they die again I think I may just bite the bullet and get Hopes. The deores are great when they work but they seem to have a lifespan of about a year.

make sure all the bolts are tight on caliper and rotor?
copper grease on the back of the pads? I did this years ago on a set of Maguras and it worked.
rough up the surface of the rotor with a bit of sandpaper?

Check for leaks carefully first: If there is a leak in the calipers it will trash any new pads quickly. Do a quick clean up first then hold the brakes on firmly for a few minutes and see if any new dampness appears.

Go to Fort William and do an uplift day.

After one run my brakes were as bitey as they’ve ever been and completely squeal free

I had the same problem just recently and found a thread online suggesting cleaning pads thoroughly with hot water and neat Fairy liquid (rubbing pads together)… worked a treat !

I cleaned my rotors with cheap diet coke (i.e. brown phosphoric acid) to remove a layer of oxidation. I also tried sanding pads – no joy. New resin pads were OK though. To be fair I didn’t do the control of new pads and no coke…

ime with shimano brakes is once the squeal sets in you need new rotors and pads.

I did manage to rescue my rotors after the dreaded leaky seal problem. I scoured them thoroughly with cream cleaner, rinsed with boiling water, then dried them in the oven. It’s definitely worth a shot as it doesn’t really cost anything apart from a bit of your time. The pads were junk though.

OK, last chance. A new set of pads has arrived. Oven will be used tonight (that saved an old rotor many years ago for me) on the rotors.

Hmm good point about leaks. (Sorry OP for jumping in)

I have XT discs.  After the bike has been sitting a while they are squealy and weak. A good 20 minute thrash brings them back to life and they are fine the next day.  But they consistently return to squealy weak.  I also tried new pad/rotor (just on the back for diagnosis).  Leak sounds plausible.  On the other hand it seems strange that front and back seem to be affected in the same way and I haven’t had to top them up or bleed in a few 100km aggressive riding.

OP – did you try blowtorching the pads then giving them as little sand as well as dishwashering the discs?  That’s worked for me in the past. BTW, I probably wouldn’t inhale any of the smoke that comes off the pads!

twowheels I had exactly the same, including the same reasoning about why it couldn’t be a leak (both went together, no obvious loss of fluid).

Stick a bleed block wrapped in a paper towel in them and pull the lever gently with a rubber band. Leave for 12 hours, inspect paper, replace under warranty.

http://blueliquidlabs.com/repairs/solving-that-brake-squeal/#more-539

Success, and an experiment….

Disc as is, quick clean and new non Shimano pads = great.

Old, uncleaned disc on non Shimano pad = great

Old Shimano resin pads on old spares disc = squeal.

New non Shimano pads on the spare disc = great.

Old, old Shimano resin pads on any disc = squeal.

So the running theme is that it is Shimano resin pads – both almost totally worn and about 10 rides old…. FWIW all other pads are either Uberbike or Clarks.

So we are back to squeeeling – both with clarks and uberbike pads.

I also have discovered they *are* leaking – oily film on edge of pad backing, on one end of caliper and on frame below….

I was about to click buy on a new set of Magura MT4’s, when I then discover that I need thicker Magura rotor’s and a matchmaker clamp thingie for my dafty Shimano integrated ispec whatever of the bloody three iterations it is….

FFS shimano.

It will be the leaky o seal problem (although last time I mentioned that half the forum told me I was talking rubbish). I had a few calipers do exactly the same thing, no discernible loss of fluid but if the bike was left unused for anything over a week the brakes squealed like mad and had no power. 20 mins of hard braking seemed to cure it until the next time.

I tried everything, cleaning, sanding, new rotor, new pads, eventually always the same squeal.

Eventually I just bought some Magura MT2 and haven’t touched my brakes since. I actually took a punt on some Chinese MT2 off ebay but they were spot on and came with new rotors. I sold my old shifter bought a used zee shifter with a clamp and sold the shimano levers.In all it didn’t cost much more than £30. Money well spent.

I am removing mine – a friend might have an old set I can borrow – and they are going back to Rutland for Warranty.

If they give me new ones, I am selling and buying Magura…

Check the hose join to the callper – had a little leak there on the tripster that a clip of the hose and new olive sorted (new pads and a clean up too to be safe).

Mine were smoking heavily after a pretty short descent which I’ve never seen before, but didn’t squeal and stopped properly for the rest of the ride after. Few days later and they’re back to squealing again! These are the very first ‘good’ xt brakes that I bought when they first came out 6 years ago or whatever so can’t complain.

Spray rotors with brake cleaner and put a match to it. (wear protective gear don’t try this at home always have adult supervision keep out of reach of children etc.)

Tip from my LBS and stopped my Shimano road brakes from honking.

It’s back.
Last three rides I’m down on power and squealing again.

A few thoughts – a few rides before was Laggan, before that Ben Ledi. Perhaps I’m cooking pads or fluid or seals? See below for my pad (right) and Mrs_oab’s on left. Both Shimano resin put in at same time…

So, do I dare go through the rigmarole and lies that is Rutland again or what…?

(Ps, we’ve four sets of Shimano in the household, three Deore and one Xt, before that three sets of SLX and XT. No issues until they were 5+ years old)

Got to be seals again. I don’t know Ben Ledi, but I know Laggan and it’s not an obvious brake cooking spot. Maybe clean it all up and if it goes again it’s seals and you are back into warranty faff.

The backing plate on your pad does look dusty/oily too.

Have you tried the o-ring fix mentioned above?

Have you tried the o-ring fix mentioned above?

They are new calipers.

It’s a regular occurance with Shimano brakes, sometimes even on brand new bikes. A few years back, I bought XTs to replace ancient Hope Mono Minis rather than doing a full rebuild, two years, two levers, and four leaking calipers later, i’d gone back to Hope for a set of Tech Races, and been trouble free ever since. All the parts were warrantied, but the faffing and uncertainty of how long before it happened again made it worth the swap.

They are new calipers.

You should have sold them and gone for Maguras… 🙂

It does sound like you’ve been unlucky to get two bad ones in a row.

Replace Shimano with a brake manufacturer who can make seals that hold fluid in on a more regular basis I reckon. I’d be looking at Sram Guides or Magura MT5’s I think.

I’ve had one set of deore’s which were ok ish (but not wildly powerful) and they went all squealy and lacking in power with very little use so I sold them and bought a pair of Guide r’s off eBay for £80 with a bleeding edge bleed kit. Had been used a few times before being replaced by Hope as the guy preferred them. I know a few people who have had leaky shimano brakes too.

I am Magura curious though next time I need brakes

one of left looks normal the right not so much.

Was that not me Joe? 🙂

I’ve just sold the Hopes to try the new Shimano 4 pot brakes too! Fingers crossed eh?

Ah yes, maybe it was John, they’re still going strong on a different hardtail I’ve built. Now with uberbike race matrix pads in them they’re really good!

Not sure I’d sell Hopes to go to Shimano though……