They were previously filled with Shimano mineral oil. Now they are to be re-purposed for dot 5.1 oil. Any issues with doing so?


  • You probably can do that after cleaning the insides of the hose, but I have no idea how to reliably perform the job. Maybe flush the hose with alcohol and blow some air into it? Jun 28, 2018 at 0:20
  • 2
    Hose is cheap - just replace it. Brakes are the single most critical part on your bike.
    – Criggie
    Jun 28, 2018 at 2:05

1 Answer 1


Technically you could, but it's a very bad idea.

The two fluids are incompatible and will contaminate each other, forcing you to re-bleed sooner than expected.

Whichever solvent you use to clean out the hose of mineral oil, will also be a contaminant for your dot fluid. In addition, you'll need some serious dedication and resolve to make sure you actually clean it out completely.

Labour + more dot fluid > Cost of length of hose.

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