Tektro Auriga Comp hydraulic brake. I needed to add fluid to my brake, and decided to do a bleed. I used DOT 3 fluid instead of mineral oil (Very stupid me). after a few days my brake went dead (there is not fluid, must have escaped through a damaged seal).

Question: What seals/things must I replace in the brake - I do not wish to purchase another brake (but will purchase correct fluids in the future)? Do I replace all the seals/rubber parts, or are there more parts to replace? Can I buy a 'kit' that contains all the parts needed to replace?

  • It's probably worth a try to flush out the DOT, fill with mineral oil, flush that out, then fill again. Then look for anything that's leaking. Using mineral oil in a DOT system would be bad, but going the other way is probably not quite so bad. Commented Aug 27, 2017 at 18:25
  • I'd have thought the exact opposite, @DanielRHicks. DOT fluid is nasty stuff, can take paint off if you spill it.
    – alex
    Commented Aug 28, 2017 at 6:15

2 Answers 2


Every non-metal part touched by the fluid could have been damaged by it, and none of it is available as service parts other than the hose. Especially given you're already seeing evidence of the seals degrading, replacing the whole thing is all you can do.


Throw it away. You've compromised everything that is plastic or rubber or sealed, and also any metal parts that are bronze or brass.

You need a complete new brake system, and stick a label on it to remind you what fluid to use next time.

Don't feel bad - I did this to a car once... it was a lot more expensive.

  • Don't all cars use DOT fluid? I'd have made that mistake if there wasn't.
    – RoboKaren
    Commented Aug 29, 2017 at 17:49
  • @RoboKaren Citroen used mineral oil in their brakes for a while, as did Rolls Royce. Magura "Royal Blood" is mineral oil too. Also, DOT3 / 4 / 5 / 5.1 are not generally compatible either, mixing or changing "grades" is not a good idea.
    – Criggie
    Commented Aug 29, 2017 at 20:38
  • I tend to agree. I will replace the entire break...
    – DAG
    Commented Aug 30, 2017 at 18:53

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