Shimano caliper 'misting'.

[Bearbonesnorm]

I've just had a warranty claim ok'd for a pair of Deore brakes and wondered whether anyone else had come across the same problem (I recall Colin saying something).

Problem manifests itself with an initial lack of bite and quite a bit of squealing. Clean discs, change or clean pads and all seems well. Leave the bike stood for 10 days or so and the lever's a little on the spongy side. Bleed brakes to regain lever only to discover the bite has gone again and the noise is back. Keep repeating this cycle until you eventually realise the caliper has a 'micro leak' and whilst not actually dripping fluid from the seals, it is losing enough to deposit a very thin film on the discs / pads.

[slarge]

Had exactly the same with my old XT calipers. New calipers is the only fix as Shimano don't sell seal kits. Calipers on their own are more than a set of SLX. Disappointing performance by Shimano in my book - my Hope brakes have never suffered this.

[Bearbonesnorm]

I've only experienced it on Shimano too Steve but given the frequency that some people seem to bleed their brakes, I wonder whether it's actually quite common?

Luckily, this set weren't quite 12 months old, so I now have a CRC credit note to the sum of. Bike is now sporting BB7's

[Trail-rat]

Its standard shimano.

They don't get anywhere near my bike now

Especially as -go try and get a new set of seals.

Wasteful and pretty mediocre brakes.

Got 4sets of hopes 3 sets of bb7s a set of depression cables and a set of Hayes cables.

All perform better and more reliably over the years than the 3sets of xt I have worked through innthe past.

[Trail-rat]

I should point out that not all those brakes are mine.....thats in the household

[Charliecres]

For balance, I love Shimano brakes, including the set of 12-year-old Deores on my Swift that had their second bleed last year and still work perfectly.

[ScotRoutes]

This seems to have been an issue on a small proportion of Shimano brakes (that's a small proportion of a very high number remember). Replacement is the only option.

AFAIK it seems to mostly affect the x8x series, not the earlier x7x or the new x0000.

FWIW I've also read enough to convince me that only genuine Shimano brake fluid should be used.

[jam bo]

I had similar symptoms on a set of xt 780's. Couldn't get any consistent power on the rear.

Swapping the rear disc for another has solved it and it's not come back in another 6 months of riding.

[Zippy]

hmm, interesting, wasn't really aware of this. It might explains something - but I've not had it as bad as you describe Stu.

I still rank my XTR's overall better than my Formula R1's and deffo better than any Avid hydraulic brakes I've owned - hope are a mixed bag too - but not used them for a long enough period of time to fully comment on them. Yeah, I run shimano's on all my bikes - and probs still will overall.

[RobLyon]

I've got this with a Set of M615 Deores. By the time i'd realised whats going on the warranty period expired. Do we reckon its worth trying anyway?

Edit: Done, nothing to lose

[Bearbonesnorm]

I've got this with a Set of M615 Deores. By the time i'd realised whats going on the warranty period expired. Do we reckon its worth trying anyway?

Nothing to lose, they're pretty much scrap as it is.