Do Shimano brakes just go bad?

I've always used this technique to bleed Shimano brakes and never had an issue -

Between full bleeds, if I've ever had any slop in the lever then a lever burp bleed i.e.

has always sorted it.

I've heard about the 'micro leak' issue with XT brakes before - supposedly bikes stored in the garage for a long time imperceptibly leaking mineral oil onto the pads, causing loss of performance when the bike is taken back out for a ride. I've experienced those symptoms once before after the bike was stored for six months, and new pads plus deep rotor clean and rebedding in sorted it.

On the flip side I've had a couple of sets of recent generation Shimano brakes (XT 2 Pots and XTR/Saint hybrids) and could never get them set up consistent with each other (XT had horrible wandering bite point, the XTR/Saint rear always needed a squeeze before it felt OK) despite numerous bleeds following various pro-tips (inc the one posted above).  Maybe it's just me not doing it 'right' but I don't have the time to constantly faff to try to get things right when there are other options out there.  

I'm on Hope E4s for my mostly used bike and they are easy to work with, consistent and solid.  I 'downgraded' the XTR/Saints on my uplift bike for a set of Code RS I had spare, they're not as nice as the Hopes, but at least they feel consistent. 

My experience is that wandering bite point is less common than it used to be, and I can usually solve or work around it. Calipers can get sticky though, I have an awkward one on my Zees at the mo.

I've heard about the 'micro leak' issue with XT brakes before

I was sceptical about this, but I've had it with a couple of Deore 6120 calipers in the past year. Very disappointing, especially when I realised they were more than 2 years old.

I've moved to Saints on my main bike, and - touch wood - they have been brilliant so far.

So I'm sticking with Shimano as a known quantity for now.

I suspect sticky pistons.  Caliper off, pads out, work the pistons in and out and lube with a bit of mineral oil

Couple of other things you could try:

Someone on the fork oil thread suggested that light weight fork oil can solve the bite point issue? 

ZRACE or IIIPRO calipers from ali-express? Apparently they (might need new hose fittings depending on your specific caliper) can be a straight swap. 

I've not had to try either but the logic seems sound?

All brakes rely on "rubber" seals. They're inevitably going to degrade with time and use and performance will suffer.  

One of the reasons I favour Hope is that you can buy all the parts and even better, send them back to Hope for a full service at a reasonable price. I had a set that were getting rub/heat issues and new seals and pistons made them like new again.  

'm sure the same applies for SRAM and Shimano as well -  there are 'aftermarket' kits for Shimano online even if you cant find OEM.  

 I don't like the disposable nature of Shimano, 

there are 'aftermarket' kits for Shimano online even if you cant find OEM.  

It comes down to effort and cost though. 

Hope calipers are expensive because ..... reasons.

Shimano calipers are cheap because ..... different reasons 

You could rebuild a Shimano caliper, but what's the carbon footrpint of that lump of aluminum? Probably about the same as your lunch.

Is the carbon footprint of a Hope caliper CNC'd from a lump of aluminum generating several times it's final weight in waste material really lower than the forged/cast shimano calipers that generate far less waste?

It's the same with car's, the cost of a rebuild kit for mine was the same as a new pair of caliper.  I only found that after spending most of a day stripping, cleaning, painting and rebuilding them, and now the paint is flaking off and they look worse than ever.,

Literally walked in the door from picking up my bike after having my XTRs serviced and the mechanic said Shimano brakes do seem to die a slow death. I'm a week away from an Alps trip and now thinking maybe I should buy something else (had problems with my brakes out there last year but figured better pads, bigger/thicker/multi layered rotors and a fresh bleed might sort them)

How thick is the rotor (especially if you've been sanding it)? The minimum width will be engraved on it somewhere and it's worth checking. 

FWIW all my Shimano brakes just seem to keep on working. I might decide to bleed them every few years but, other than that, don't have any issues. 

I'm a week away from an Alps trip and now thinking maybe I should buy something else (had problems with my brakes out there last year but figured better pads, bigger/thicker/multi layered rotors and a fresh bleed might sort them)

My rear 6120 started feeling a bit crap. I was bleeding it weekly and it never really felt right. Cleaned and lubed the pistons etc.

I changed the bladder thing in the lever and it's perked right up again.

I couldn't actually see anything wrong with the old bladder when I took it out. Either stripping the lever and filling it up with fluid worked out a stubborn bit of air or there was a tiny hole I couldn't see...

Either way, it's back to rock solid now every time. 

FWIW all my Shimano brakes just seem to keep on working. I might decide to bleed them every few years but, other than that, don't have any issues. 

Every few years! Mine barely last 6 months. However I finally seem to be on a set that hasn't started leaking in the normal timeframe. 

Posted by: rsl1

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Every few years! Mine barely last 6 months.

I just checked. I have 3 MTBs with Shimano XT M8000 brakes. Build dates are 2015, 2017 and 2019. The 2015 and 2017 set had a fluid change a couple of years ago as I was doing a "Spring"  maintenance cycle anyway. The other one hasn't been touched, other than new pads. I'll probably do it next Spring. 

I also have a couple of road/gravel bikes with Shimano brakes and was getting excess lever travel with the oldest one. That's when I checked rotor thickness...

That's when I checked rotor thickness...

Good tip this, so easy to forget.

If it feels too think between fingers, just bin it and you'll be surprised how much better your brakes will feel with a fresh rotor.

My tech3E4s are going strong. One rebuild and a couple of bleeds in a decade or so. 

I've had a few Shimano fail, one was the piston crumbled at the rear and blocked the hose. 

Posted by: chakaping

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I'm a week away from an Alps trip and now thinking maybe I should buy something else (had problems with my brakes out there last year but figured better pads, bigger/thicker/multi layered rotors and a fresh bleed might sort them)

 

If they're working well now, you'll probably be OK - but I'd get some posh pads and give them a shakedown ride first.

 

My standard resin pads went all squealy and horrible last time I was out there.

Bike shop recommended some Shimano pads so even though I've got loads of spares from Uberbike (sintered and the ematrix ones), I've ordered some finned Shimanos anyway...

Another vote for checking rotor thickness. Have you done 5000 km on the original rotors?

Thanks for the responses.

Definitely not rotor thickness (but a good shout to check), I measure with a micrometer and recently replaced the front.

I've ordered some replacement bladders, will try those plus a solid bleed before writing them off.

Posted by: thisisnotaspoon

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s the carbon footprint of a Hope caliper CNC'd from a lump of aluminum generating several times it's final weight in waste material really lower than the forged/cast shimano calipers that generate far less waste?

the alloy shavings are reused so no extra waste just another bit of energy to melt them down again

I've just this evening resurrected a bike I haven't ridden for at least three years. The 2015 XT brakes needed a bleed, howled like anything, but after half an hour or so had settled down. We shall see what the long term effects are, I suppose.

Bike shop recommended some Shimano pads so even though I've got loads of spares from Uberbike (sintered and the ematrix ones), I've ordered some finned Shimanos anyway...

Take some spare sets as well obvs.

On the subject of finned pads, I did this a while ago and it's been helpful in reducing the rattling:

View this post on Instagram

^ that's standard procedure whenever I've been flush enough to have finned pads - I HATE any rattle on the bike and these were doing my nut in without padding. 

I generally run Shimano's without issue. Had micro leaks on a couple of sets that were in daily use on commuter and subjected to horrible winter road conditions. Generally Shimano are reliable for me.

I spoke to one of the Shimano tech's at the Malverns a couple of years ago about my brakes when I was getting frustrated at them.  He sorted them right out but did suggest not to ever let the pads get below 1mm of pad material as the pistons have to come out too far and get a bit wobbly (or something).

Makes pad life a bit short but it's not bad practice and makes sure you've got lots in reserve for those wet days. 

This thread is a reminder that I do need to bleed my brakes.  Not sure I've done it since before Morzine last year.