Iv just had the last four days in the north, however for 2 of those i had no rear brake at all! The lever touches the bars totally and i can spin the wheel still. I thought at first it may of been the pads after such a wet BB weekend but on buying new ones at Keilder they were still not working. Even pumping them has little effect .
They feel like theres no resistance in the system and i can not see any leaks or oil any where. Hmmm have i read somewhere about xt failing?? Anyone had this problem with shimano brakes....is the caliper dead or are they maintainable

my xt were like that a few weeks ago on the single speed mike ,
bled them with new oil and they are back to normal now

paul are they easy to bleed or do i need a kit

Mike wrote:paul are they easy to bleed or do i need a kit

Yes but yes. Some good video tutorials on YouTube

They are knackered when they work some of the time!

I just got a kit from flee bay for £12. with oil \tubes and all the bits ,
and just got on youtube to see whats what

How old are the brakes Mike? My XT brakes lasted about two years then they started to get very spongy in feel and no amount of bleeding would sort them out. In the end I replaced with Hope brakes.

Edit: I originally said three years but Sean's comment about the warranty reminded me that it was around the two year period.

they are only about 1 yr at most

Mike ,try cable tie the levers back to the bar and leave for a day , the xt on my bouncy bike do the same every now and then ,tying the levers back for a day seems to cure it ,if not like burty says bleed em ,doddle to bleed with the kit

Don't all xt level parts have a 2 year warranty? I've had 18 month old pedals replaced before as there was play when clipped in.

I had a similar issue with a deore brake which then sorted itself out, but I lost faith in it so replaced the master cylinder.

I've had XT and XTR brakes fail on me, that's when they're not being crazy inconsistent. =/

Yep, a hydraulic Deore caliper failed after several months due to a piston seal problem. The symptoms were very squeaky brake, extended braking distances and repeated need to bleed, due to excessive lever travel caused by the fluid leaking from the system.

I returned the complete system to the supplier; a new caliper was fitted and bled free of charge.

However: in the meantime I'd fitted a cheap pair of Shimano cable disc brakes. They work so well with the 180mm rotors and are so simple to maintain I haven't bothered to refit the hydraulic brakes.

In my experience (from both personal use and bike shop mechanicing) any inconsistency issues are resolved by a successful bleed.

Mike as per MAM - tie lever back to bars and leave for a bit (I've found 20 mins usually does it although overnight is better) and you should get a brake back. It seems to be a foible of shimano brakes - it means there is air in the system which can get in the wrong place when you push the pistons back in to change the pads, or pump the lever with the bike laid down. Tying the lever back seems to allow the offending bubble back into the master cylinder. A thorough bleed can sort it

htrider wrote:Mike as per MAM - tie lever back to bars and leave for a bit (I've found 20 mins usually does it although overnight is better) and you should get a brake back. It seems to be a foible of shimano brakes - it means there is air in the system which can get in the wrong place when you push the pistons back in to change the pads, or pump the lever with the bike laid down. Tying the lever back seems to allow the offending bubble back into the master cylinder. A thorough bleed can sort it

And if this overnight treatment does the trick then it’s worth popping a couple of drops of extra fluid into the reservoir as this will stop that air getting back into the system later.

I once had an XT brake that for a bit disconnected from the piston on the master cylinder... (after a crash admittedly!). Yours sounds more like than that a load of air in the system. I think it was some misalignment - I bought a new lever etc. for it, but haven't ever got round to fitting it and it's been fine since giving it a tap

Bleeding new shimano brakes is easy - just normal bleeding, but you need (well it makes life a billion times easier) the funnel thing that you screw in the top (a few quid). .https://www.chainreactioncycles.com/shi ... -prod34710

Bought a funnel and did it today. The old oil looked like it was contaminated with water that horrid grey muck when oil n water mix. Anyhow flused new stuff through but the lever is still a tad spongy. If I squeeze it once it will then bite hard and work as a normal brake but not sure It should need that first squeeze?? Well the front one dont. It looked like some oil had come out of the lever underneath I wonder if the seal has gone in the piston??

Mike wrote:Bought a funnel and did it today. The old oil looked like it was contaminated with water that horrid grey muck when oil n water mix. Anyhow flused new stuff through but the lever is still a tad spongy. If I squeeze it once it will then bite hard and work as a normal brake but not sure It should need that first squeeze?? Well the front one dont. It looked like some oil had come out of the lever underneath I wonder if the seal has gone in the piston??

That sounds like a possibility. But try the zip tie lever overnight trick to see if there’s still air trapped.

Nothing to lose.

It's on already

Shimano fluid will turn dark as it picks up some colouration from the seals. If your lever still needs a couple of squeezes to work then I suspect you still have air in it.

Back brakes are normally harder to bleed as the hose is longer and tends to be horizontal in places. If you can remove it from the bike - or rotate the whole bike to make the hose vertical - you might have more success.