I’ve read up on god knows how many threads / sites about leaking seals on Shimano brakes, and now face the problem myself with some first generation M785 XT brakes.

Have suspected they are suffering for a while as the first few miles or so into rides they are always lacking in power or squeeling if it’s remotely wet. Then they come back so all is good.

However I’ve just had a lay off the bike for six weeks and went for a ride yesterday. This time they didn’t really come back after around an hours riding so I want to do something about it.

At first it was an excuse to change to something like XTR trail, then read that they suffered the same crappy o rings. So I decided on Hope Tech 3 E4.

Then a reality bone in my wallet snapped and suggested just to replace the XT calipers for a fraction of the price.

XT has worked well enough until this started happening.

The question is – Is it likely that it is just the calipers suffering with seal issues or potentially the levers too?

Don’t really want to buy the whole lot in two orders, or really buy more of the same if the problem still exists.

Dunno how many of the new ones have been affected?
I think you have to be just lucky!
I think it’s just the calipers that have been affected.
On my third road caliper after juggling with the warranty department for the past two months.
So far a silent caliper with no squeaking!
If it goes again I will be going straight to Hope!
Thanks,
Max

Cheers Max.

Think I’ll spend the £70 or so on two new calipers and see how it goes.

Hope levers do feel so much nicer but that isn’t enough to justify an extra £200 if the new calipers give me brakes I remember from a pre leaky state.

Ffs Shimano!
This has been going on for years now.
It’s time they got their act together.

Oops, just had a set of Zees from Merlin delivered.

Hard not to at the price, and if they don’t last I’ll be sending them back and moving to Hope.

I’ve read up on god knows how many threads / sites about leaking seals on Shimano brakes, and now face the problem myself with some first generation M785 XT brakes.

Same brakes, same problem. My lbs is going to fit new SLX calipers…

Why cant they fix this…?

Why cant they fix this…?

The Shimano hydro brakes on my commuter are the cheapest, nastiest ones they make – of course, they’ve been absolutely flawless.

For all that it’s a pain, shouldn’t happen and needs a solution, I’m guessing that the total number of failed units is a miniscule percentage of the total. For balance, in our fleet of hire bikes there are 50-odd pairs of Shimano hydraulic brakes and we’ve had zero problems. I personally have had no problems despite a range of XT and XTR brakes on my bikes either. If everyone who’d never had a problem posted then perhaps that would provide better perspective.

One thing I do insist on is using genuine Shimano brake fluid but alternatives can’t be the cause of all the problems either as I’m aware of some that still had the original fluid and have never been changed.

For all that it’s a pain, shouldn’t happen and needs a solution, I’m guessing that the total number of failed units is a miniscule percentage of the total.

My LBS mechanic thinks he’s seen it about twice…not much comfort to me though!

I fixed a leaking reservoir seal on one of my Deore brakes by using super glue. Its been fine for the past year. Maybe worth a go?

scotroutes – Member For balance, in our fleet of hire bikes there are 50-odd pairs of Shimano hydraulic brakes and we’ve had zero problems. I personally have had no problems despite a range of XT and XTR brakes on my bikes either.

ransos – Member
The Shimano hydro brakes on my commuter are the cheapest, nastiest ones they make – of course, they’ve been absolutely flawless.

I wonder….does frequency of use help? I noticed that when I wasn’t using my MTB much that the brakes got squeaky.

My xt Caliper seals went, no brake power just chewbacca noises , replaced with cheapest Caliper on crc. As a bonus you get new pads. Cleaned rotor and now works brilliantly.

Could be. There’s certainly a suggestion that prolonged periods of inactivity might cause the seals to shrink but I’m not convinced there’s been enough proper analysis to come to any conclusion.

I wonder….does frequency of use help? I noticed that when I wasn’t using my MTB much that the brakes got squeaky.

I don’t use my mtb much these days – it was working fine, didn’t get used for a couple of months (stored in the garage)then I went to use it and found the brakes were all squeak and no stop. My commuting bike is used every day, and works perfectly.

My 785s on both bikes, both levers and calipers, seem to fail in their third year. I just replace the blown part, because if you shop around you can get them remarkably cheaply. For the record, SLX callipers are identical to xt. They use a split pin for the pads, but the threading is cut for the pin used in xt and above, so it’s easy to pope it straight in.

My last slx caliper was 25 quid and came with pads. Total no brainier IMO.

For your info,
HOPE now do calipers on their own for Shimano OR SRAM.

Interesting

very…

Yep that would be – MTB Rob, you need to tells us more or give a link ?

Can’t see the info. on the Hope Website.

Update, my LBS has fitted new SLX calipers, and cleaned the rotors with steam and alcohol. They are still squealing, though braking power is ok. I have a set of old rotors to fit, but is it worth baking the squealing rotors in the oven?

Not bake the rotors, no. Cleaning them with some isopropyl alcohol should suffice.
Give this a read:
http://www.bikeradar.com/forums/viewtopic.php?t=12666026

Not bake the rotors, no. Cleaning them with some isopropyl alcohol should suffice.

Yes, but the mechanic has already done that several times using clean shop towels, and he steam cleaned them as well. He also tried another set of new pads with the same result.

I can use my spare rotors (they’re from a bike with mechanical discs so no chance of contamination) but I’d like to rescue these ones if possible, as they’re quite expensive.

My 785s are doing this as well. Lack of power and the front squeals terrible. I assume there’s a slight leak ad the bars pull further to the bars than they used too. Any links to these hope calipers then?

first few miles or so into rides they are always lacking in power or squeeling if it’s remotely wet. Then they come back so all is good.

they just need a good bleed. If there is no obvious leaks its not the seals. Squealing, yeah sometimes when wet but that’s not a lack of braking. Just noise, ignore it soon disappears. New pads etc and cleaning rotors just wasting money.

the bars pull further to the bars than they used too.
[quote

also needs bleed.

When you bleed them make sure the calliper hose is straight up. take the calliper off and let it dangle. This ensures and air escapes up the pipe. Applies mainly to rear. Front in my experience is never a problem.

Had my XTs for 3 plus years so far, bleed I guess when I have the above problems. Often notice it when the bikes been laid down in the car.

I also notice that when this happens that the fluid is black! Clearly needs a change so I give it a good bleed until clear oil comes through. The oil will degrade over time.

You might try buying some Deore calipers to replace the XT ones.

I don’t think there’s much point replacing XT calipers with XT ones – you will eventually (in my experience anyway) get the same problem. Seems like too much of a gamble.

I’ve got some Hope Tech brakes on order from Merlin, which I think should fix it once and for all, as I’m now bored of this particular game.

MTB_Rob isn’t that road calipers not MTB?

http://road.cc/content/tech-news/203735-eurobike-2016-hope-show-new-road-calipers-and-hubs

Yes, but the mechanic has already done that several times using clean shop towels, and he steam cleaned them as well. He also tried another set of new pads with the same result.

I can use my spare rotors (they’re from a bike with mechanical discs so no chance of contamination) but I’d like to rescue these ones if possible, as they’re quite expensive.

Update: I scrubbed the rotors with cream cleaner, rinsed with boiling water, then put them in a hot oven for 20 minutes. Worked a treat – plenty of power and no squealing.

I had the problem with deore with original pads after a period of inactivity. Right pain in the arse to sort but eventually was by changing pads and cleaning the absolute shit out of the rotors. Wet and dry, ipa, oven, the lot. Since then been ok and running uberbike pads, even been ok with another period of inactivity. Got me wondering, you think it’s possible for the shimano resin that has been laid down on the rotors to cure into something slippery and squeaky if it isn’t scrubbed off and replaced through regular use?

pawsey bear – the leaks are tiny – just enough to contaminate the pads and unless you have a fault that allows air in bleeding will do nothing.

Pawsy. Leaks dont have to be visible to the untrained eye.

I found mines was leaking by putting paper between the pads and pistons.

Was obvious it was leaking

Update: I scrubbed the rotors with cream cleaner, rinsed with boiling water, then put them in a hot oven for 20 minutes. Worked a treat – plenty of power and no squealing.

Wet and dry and soapy water has never failed unlike chemical cleaners which seldom work. Was it was an abrasive cream cleaner?

Your money may be better spent on goodridge hoses with their quality fittings, that’s what fettled my M785s once and for all. I find the appalling quality Shimano hoses and fittings are the root of all evil as they develop micro leaks that are not detectable.

I have never owned a set of disk brakes from any manufacturer that didn’t squeal in the wet and I find that once Shimano are heated up the squealing stops.

I had this. Replaced under warranty, same problem. Now replaced with Hope as I just couldn’t be doing with the squealing and lack of power any longer. Not yet had a problem.

Strange as once i got rid of my shimanos brakes dont squeel in the wet anymore (hope mono minis of various vintages dating back to the first set ups and a set of bb7s)