I’m having a specific issue with Shimano XT brakes (new ones) and hoping someone has a solution.

I don’t believe it to be a bleeding issue as it’s been bled by me countless times (with Shimano fluid and the little cuppy thing, had the lever clamped overnight, tapped the hose, dangled the hose vertically etc etc) and by the shop twice (by a decent mechanic) yet the problem persists.

I’m getting inconsistent lever feel from ‘normal’ to ‘rock hard with minimal lever travel’. It doesn’t go spongy or back to the bar.

It happens seemingly at random and not necessarily when the brake is warm (from dragging it for example). It could be straight away on a decent but then not at all on another decent. Usually, a couple of pulls on the lever sends it back to ‘normal’ again even mid decent?

Anyone else had this?

very similar.
Not “new”, but at about 2 years old approx.
Bite point becomes inconsistent and may or may not return if pumped.
Had this happen on three separate sets of XTs on three different bikes.
Bled them and this often showed black fluid at the lever end. Strongly suspect this to be indicative of seal degradation in the lever.
Performance marginally improved by bleed but problem soon recurred.

I’ve found the most effective solution to be following this step-by-step process:
1. Return for warranty replacement (2 yr warranty)
2. Flog replacements whilst still brand new in box
3. Swallow pride as a previously loyal XT devotee
4. Buy Hope Tech3 E4

Lever seals. If it’s still new. Get it warranteed.
785s did this too. Mostly, mine do it after 2 years ish too. I just replace the offending component. Also I don’t see any value going above SLX level these days.

I just replace the offending component.

That was my first approach. A Shimano lever is not a silly price to just treat as a consumable item, much like a set of pads or a rotor.
… BUT …
Then eventually it happened on a particularly narrow set of steps in Hebden Bridge. Rear brake pulled to the bar and I had to try and control on front alone. Failed and went OTB.
Yes, cost wise, another XT lever is the sensible option.

Mine have never failed catastrophically like that. It’s always been more of a gradual deterioration o veer a couple of months. I expect if it does I’ll change my opinion too!

Overfilled, did you use bleeding blocks, wrong fluid?

Overfilled, did you use bleeding blocks, wrong fluid?

Regarding my own occurrences…
No, Yes, No.

[edit] I’m with Scienceofficer on this, I’m absolutely convinced it’s seal degradation in the lever [/edit]

My XTR did the same and it appeared to be the seals in the levers. Was just over two years old but fortunately xtr have a slightly longer warranty so it was replaced under that.

I don’t have a great deal of love for my new XTs to be honest. There’s something weird going on with the rear lever in that it will randomly pump out a point during the ride. One pull of the brake and it resets itself.

Would be tempted to try going back to Hope next time although I have my reservations there.

Sadly I gave up on the big S brakes. I tried to fix them shops tried to fix them.
Second hand hopes were miles better. No regrets as yet.

It’s been a long while since I’ve had hopes (1st gen monos with black and gold), but I always found them a bit fussy and needed alot of tweaking.

It’s been a long while since I’ve had hopes (1st gen monos with black and gold), but I always found them a bit fussy and needed alot of tweaking.

My experience also. Looks like it’s Avid then…..

They came on a new bike, 2016 Whyte T130 RS, only been ridden 4 times and had issues with them on every ride despite the work done by the shop and myself.

Never been a Shimamo fan to be honest, always liked Avids and the Guide RS’s on my Capra are great brakes.

The shop has offered to exchange them to anything I want, giving me CRC cost price for the XTs as an offset. Might switch them to RS’s.

mine was a sticky rear piston, 3 times. it would stick on one side and jam at an angle in the caliper.

sacked them off for a new set of Formulas on a whim that i had lying around and never dared to use. could not be happier with those.

Would still never ever ever buy any brakes from SRAM/Avid though..

Would still never ever ever buy any brakes from SRAM/Avid though..

Why’s that out of interest?

Very Expensive spares, and generally bastards to bleed for average performance would be the first place to start.

I have the same problem – rear brake goes to the bar and does nothing, gets usable after a bit of pumping. So far not ended up going OTB.

Front brake has just gone back under warranty because of the leaking caliper problem (waiting to be returned).

So far my fix has been to replace the front with an Avid BB7 and the rear with an old Deore. It’s completely fixed the problem.

The old black and gold Hopes were finniky but the newer silver and black ones and onwards are a lot better, I’ve still got some silver/black minis that are years and years old that are still going strong, I think when they went to phenolic pistons they sorted em out,
still got some ancient Formula Oro Bianco’s that refuse to die and still work perfectly..
still got some LX and 960XTR brakes on the Mrs’s bikes that are still good and have a nice feel at the levers, but I’m not so keen on Shimano since they got all that servowave stuff, I just don’t like the on/off feel, and things like cailpers being disposable bothers me
If I had to buy now it’d be Hope or Formula..

I had this with a new set of XT brakes after I’d changed the hoses. I was sure I’d done the bleed properly but the lever would randomly just go through its travel with no effect.

I later refitted the original hoses (the reason isn’t important) and did a full bleed again. They’ve been absolutely perfect ever since. I can only conclude that my original bleed wasn’t good enough.

The degregation in the master cylinder seals is ‘pin holing’ develops quicker in dot fluid brakes due to corrosive nature of dot.

Also happens in mineral oil brakes, it’s the repetitive cycle of pressure change when pulling the lever that micro pin holes the MC seal.

Bleeding will provide a temporary fix until any real pressure (rider+bike moving) is induced into the system and leaking resumes.

Avid actually moved their MC diaphragm to Nalgene to increase the working life, this is why many brakes could not be “bled” despite the technician doing it 100% right

Despite the media touting the new guide brakes as as good as shimano i have to disagree, they still have the same reliability issues acids always have and they are annoying to bleed.s been far too many that just fail. Last set failed as they didn’t have enough fluid in them from the factory. SRAM qc is utterly shocking.
Despite shimano having a few issues with the XTS, they are still the best in class

Pumping up of XT m8000 brakes (solid feel but changing bite point) is a known issue acknowledged by Shimano / Madison. Tell them you want them swapped under warranty – they should change the lever / master cylinder but leave the caliper. You want the latest versions, nothing with NG on the silver sticker on the levers. I’ve just had mine swapped (3rd rear, 2nd front) and the batch sticker has been removed. I was on set a set of Zees whilst waiting and couldn’t get the rear to not rub.

Shimano have really screwed up with the m8000 brakes. If this latest set do the same I’m giving up with Shimano which is bloody annoying as they’re plenty powerful with great modulation.

Tldr – buy Guides, Hopes or Maguras.

All my Shimano XT problems went away permanently after fitting goodridge hoses. Have them fitted to XT on both my bikes, they deliver consistent powerful braking with zero issues. Two friends have resolved XT issues with the same.

I reckon Shimano’s cheap hose and dreadful fittings (crimped on!) are entirely to blame.

Remember you get a 3yr warranty on XTR. 2yr on all other Shimano. Same issue with my M9020s. 18mths old. Bite point all over the place. Gutted as have been a Shimano devotee for years. My set currently with Shimano for repair or replacement.

Mine arrived back (repaired) today. Not ridden yet. Return to ROSE was free and turnaround was 3 weeks, though ROSE told me “10-14 days”. Had to chase to get them back when they suddenly appeared on the day I enquired. Appears ROSE used a 3rd party Shimano dealer/repairer to fix them.