I bought a pair of hydraulic brakes (Shimano BL-M395) for my MTB. After 8 months (less than 1,000 kms), both (front/rear brake) started to leak oil thru pistons, rendering pads contaminated and the brakes unusable.

Being unserviceable (except for bleeding), the caliper or the whole kit must be replaced in case of problems. That's not cheap.

Thinking about buying a new pair, I wonder How long will last typical consumer level hydraulic brake (years, kms)? It's something you have to discard and replace every year?

  • 1
    These are Acera level brakes, which is on the lower end. I really wish they'd try to keep things more simple (ie. cable actuated) on their lower end components. Way easier to repair at home, and a lot less that can go wrong.
    – Kibbee
    Commented May 20, 2015 at 10:55
  • 3
    I've never known brakes to fail in the at amount of time. Were they brand new when you bought them? That's an accelerated failure of the seal which would suggest something being wrong (DOT4 used instead of mineral oil for example). If they are as they came I'd speak to Shimano about a warranty.
    – DWGKNZ
    Commented May 20, 2015 at 19:33
  • Even the cheapest hydraulic brakes should live much more.
    – Alexander
    Commented May 20, 2015 at 19:47

1 Answer 1


Shimano warrants to the original retail purchaser that the Shimano bicycle division product for which they received this warranty, is free from non-conformities in material and workmanship for a period of two years (...)

As you can read in Shimano's North America homepage. So if you bought this new, go there and complain.

Disc brakes with proper maintenance should last for a few good years even on an daily usage basis, and Shimano's are known for their reliability.

If you bought them used or did something you shouldn't (incorrect oil for ex), you can try to get them fixed, but since they're around $35 each, lever and caliper, I'de just buy new ones.

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