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Getting really fed up with these XT brakes. I keep them immaculately clean and always apply proper brake cleaner after every ride but the notorious squealing just gets worse with time. Changed the rotors and pads (shimano ice tech) and they were truly AWESOME for about 5 rides then have slowly but surely got crappier...again.
Was thinking about simply buying new callipers in the hope this will resolve the longstanding piston oil leak that seems to be affecting these. Anyone tried this and if so how successful?
On a slight aside, has anyone had any luck with getting their brakes resolved via Shimano? I bought them from Evans but haven't tried the warranty route as I can't be bothered with the hassle and life is too short.
XT brakes
Various pads - sintered/ kevlar/ organic etc
No squeal unless it's wet and only for a second or two
No brake cleaner ever goes near them
Apparently Shimano are very good at warranty replacements.
Personally, after a brief flirtation with Shimano brakes a few years ago (M785 and 675's) I decided they were no better than Avids and I actually found them harder to bleed well, so when I got a bike with Guide RS's on it and decided I really liked them, I've replaced most of my hydraulics with further (SH) Guide RS's...
As I understand it, if you're up for swapping out calipers in the first place, then it's up to you if you want to buy a set or not - Shimano are quite likely to want to replace your calipers, so buying a set of replacements is probably going to result in a spare pair on the shelf - but keep you riding.
Have them on nine bikes between us. Had one of the new ones fail, a front, at the lever end in the Alps last year. Took it back to Evans and had a new one back under warranty within a week.
Only seems to be the recent versions that have issues. I replaced all my Avids with Shimano about 2 years ago and haven't had a single problem.
psycorp do you actual ride down hills with them? they are quite frightening when all power goes and you have to pump feveriously !!!
The recent version would be M8000. They've only been around for a couple of years. I've seen problems reported with those and with the previous M780 series. I did have a problem with M8000s just after I'd fitted them to my Pact. They'd randomly just lose all power, even if the lever was right against the bar. Pump them up and it would go away for a while. I then followed the bleed process exactly and have had over 12 months of faultless braking.psycorp - Member
Only seems to be the recent versions that have issues.
Is it possible that they're [i]too[/i] clean?
Why not get em properly filthy then just flush out the excess with the garden hose?
Legend has it that with old-school Hopes, the factory downhill team engineers used to take jars of Barnoldswick clag all over the world for bedding-in purposes.
I had one set replaced by CRC under warranty due to the caliper leaking oil. The second set failed in exactly the same way shortly after the warranty expired 🙁
I've now got Hopes, and not had any problems since.
Additionally the Hopes feel so nice to use I would never go back to the Shimano brakes.
Why not get em properly filthy then just flush out the excess with the garden hose?
Once the calipers have leaked oil onto your pads, you need new pads.
postierich - Member
psycorp do you actual ride down hills with them? they are quite frightening when all power goes and you have to pump feveriously !!!
I have used XT brakes on three different bikes for years without any problems apart from a pad delamination caused by being too mean to change them when I should have. Also used in the alps over the past few years the last time for a full week on my Rocket. Not once did I experience any fade or need to pump them. Organic finned pads on 203/180'rotor on the Rocket, 180/180 on the othe two. They are M785 rather than the M8000
I guess I have been lucky
The XT brakes on my 2013 Trigger are brilliant. The ones on my 2015 Jekyll didn't feel right so I replaced them with Hope V4s. The Guide RSC on my Fatty are brilliant.
Hi. You didn't say which version they are m8000 or m785. I built a new bike a couple of months ago, wanted xt, but not m8000,as hit or miss with them. so sourced some new m785 as my set on my hardtail are 2 years old and haven't even needed a bleed even after shortening hose. Like other member said even with metal pad hardly any squealing.why are you using brake cleaner after every ride? If you changed pads and still squealing, let alone change rotas as well. And if you've got fluid leaking from behind the pistons ,then it's warranty time. I've heard you won't get problems with shimano and their warranties. You don't actually say how old they are. You should contact where you purchased them from and take it from there. But to answer your question , of course if you changed your calliper a new one shouldn't squeal, but that's assuming you bed in pads properly,with metal pads personally I do like 35 high speed decelerations to almost but not quite fully stopped. Some people do it differently but it works for me. Hope this helps
If they are mt8000's then they may have leaky piston seals - if less than 2years old then send them back under the two yr warranty/contact the shop where you purchased them from. And lay off the brake cleaner after each ride (in fact lay off it completely) - totally unnecessary and more than likely exacerbating the possibility of leaking seals by degrading the rubber piston seals
If it's the MT8000 and it's the piston seals then you can't new service packs to replace them frustratingly but Shimano will do it if still under warranty. No other option AFAIA
As mentioned above, the best brake cleaner/bedder-in by a mile is water with fine mud in it. You don't even need to use a lot, it's just a grinding paste.
If your pads are oily, just throw them away and replace, they'll never be as good again. You can roast them in the oven etc, but it's just a better idea to replace them, clean the rotor with alcohol, apply a little muddy water and go use them.
IFAIK brake cleaner always b0rks bicycle disc brakes, I have never had a decent experience using it.
I had the leaky XTs on my Yeti, causing it to honk very loudly - I replaced the hoses with ones from Uberbike and it's been nice and quiet ever since.
Also, a tip from the bike shop mechanic I used on my Tripster - It was honking in the wet (obviously not XT brakes) was to lay the wheel flat, spray brake cleaner on and put a match to it. Goes up a bit like the brandy on a Christmas pud (maybe a little more flamy!) Quiet ever since.
I'd ditch the brake cleaner pronto. You may find this strips off the layer of pad material deposited on the disc when you bed them in.
You really don't need it unless you've been working on them or if the discs have got oil or grease on them.
Try and get the discs and pads properly, smoking, hot.
I have SLX on one bike - over two years, no bleeds, never an issue. Amazing brakes. Just change the pads when required and carry on.
I have XL M785 on the other - just about to hit 3 years, no end of bleeds (by me and the LBS), constantly changing bite point, pumps up ok - rear much worse than front. Had a few times where I've gone to brake and nothing happens.
The SLX and XT of that era feel entirely different too. There's so much more dead leaver throw on the XTs compared to the SLX.
IceTech 180 rotors and IceTech metal finned pads on both setups.
Going to do another full bleed on the XTs then definitely considering new SLXs. Or just old SLX leavers?
Groundhog Day.........all issues with my 2 sets of Shimano XT (M785 and M8000) stopped after fitting Goodridge hoses. Squealing only occurs for a few seconds when they are wet but in my experience that happens with all disc brakes. Never experienced a loss of power downhill either and the downhills round here are long.
Stupid question, but why would changing the hoses cure squeal?
Because they were finally bled properly?imnotverygood - Member
Stupid question, but why would changing the hoses cure squeal?
keep the hoses - throw the brakes
So....to clarify, they are M785 brakes
What I want to know is....do the callipers eventually leak regardless of 'maintenance'.
Had Hope X2s in the past and loved the initial bite but I never felt they had the same power as XT's 'when working' properly.
Tempted to go back to them if I'm honest but man they cost a packet.
Other than changing pads and bleeding them every few years, all my Shimano brakes work.just fine. The leaky seal issue seems to have affected a number of calipers of various vintages, but against the thousands/millions of Shimano calipers out there, I still think you have to be fairly unlucky to be affected.What I want to know is....do the callipers eventually leak regardless of 'maintenance'.
As someone already posted, Hope brakes aren't exactly immune, it's just that the Hope fanbois regard that as "character", much the same way as fans of days British motorbikes don't seem bothered by the massive oil slicks they leave in their wake.
because stock Shimano hoses have appalling quality fittings to the master cylinders and calipers. They are only crimped onto the caliper end and this results is micro leaks onto pads and discs causing a loss of power, squealing and inconsistent bite points. No amount of correct bleeding will rectify this. Once you fit Goodridge hoses the problem goes away because the quality and design of the fittings is way superior and prevents leaks. I also go to great lengths to correctly bleed Shimano brakes, i.e. Vertical bleed off the bike, leave overnight with the lever pulled, then mini lever end bleed to finish off. I find this method along with Goodridge hoses gives a really reliable and consistent brake with long disc and pad life.Stupid question, but why would changing the hoses cure squeal?
Never had a problem with leaky seals on M785's when i worked in the shop despite many bikes coming through the workshop so i guess the application of evaporative brake cleaner has deteriorated the seals over time.
If they are a few years old then prob not worth replacing the pistons and seals as the bore's will be worn in to the old pistons so buy new m785's//slx if you were happy with Shimano
Carried out a full fluid replacement & bleed and spent ages making sure everything was 100%.
Used wet & dry on the new disk and also used alcohol / oven so they are 100% clean. Fully scrubbed the new pads and baked them too.
System felt great after bedding in with no noise and great stopping power....but after 2 rides the brakes were again beginning to squeal and the stoping power is gone. The lever still feels great so I'm confident the system has no air. No obvious signs of leaking....sigh!
Dug out my receipt...bought them June 2015. Booked a warranty inspection from Evans later today. Worked out that the new disk & pads lasted a total of 12 hours riding before the performance diminishes......fingers crossed they find something!
Yes, had plenty of failed shimano calipers over the years. Not on the m785's though - they've been good. In every case, I've just replaced the calipers as they are fairly cheap and it's a quick job. Certainly likely to be the quickest way to get riding again.
Once they go, there is no point persevering with brake cleaners, changing disks, pads or more bleeds. Just get some new calipers on asap.
I've changed levers before and might do it again.
The handlebar clamp on the SLX M665 cracked and had a huge dead lever throw, changed to M666 levers (same looks as M675). Used them until the bike was split up.
I still have the brakes in the shed but the M666 levers are leaking between the cover and the base. -I have new M8000 levers ready to replace them. Couldn't be bothered to warranty them
It is surprising how mixed the user experiences are for, well, pretty much everything. Most of my shimano stuff has been ok*. Got some deores on a SH bike that [i]may[/i] have the leaky piston thing but if so it's not consistent just every so often I'll drag that bike out** and no power, clean them up, lightly sand the pads and back to full power. Have had a pair old 775s start to properly leak, F&R failed at different times, both in cold weather, got some 765 callipers cheap and they're still going (probably until I use the last of my pads). Got some 785s that occasionally pull to the bar, let go pull again and they're fine, I'm fairly sure this is down to crap bleeding on my part.
And to cement the ymmv theme all my hopes have been faultless, possibly not stellar performers but no leaks or failures, mini was ok for it's time I guess but a bit crap, over heated and not very powerful, but monos, M4 and mono M4s (SH) have been used for many years with next to no maintenance.
*re-reading what I've gone on to write possibly belies this, so possibly change "OK" to "work within acceptable parameters" 🙂
**got it out last week for the first time since autumn and brakes are fine.
I replaced mine with SLX M7000 calipers, keeping the original levers. Performance seems identical, we'll see if these last longer.
Shimano do seem to be a lottery in my own experience - I've got both 7-8 year old M6** SLX that have been grand, (one bleed, ever...), yet I've also had one M785 XT that was pants, followed by a succession of warranty replaced deore twice and LX calipers that all leaked/weeped onto their pads and have all been written off as a bad experience.
The Mrs has M665 SLX on her hardtail and they've been fine for 4 years too.
SRAMs are better now that the old dodgy Juicys are history; the three year old DB3 on the fatty have been fine so far, with hard use too.
Hope- I've not had any bad experiences with them, quite the reverse, still using a pair of original 2002 Minis at least once every week; factory serviced just once at reasonable cost and they just trundle on, pad change after pad change. Mono M4s and modern X2 have been just as good, with two pairs of each in our fleet.
Ditto to advice above re brake cleaner. Horrid stuff, keep away... It's just a product looking for a job, not needed.