I wish to shorten the hose on a hydraulic brake system (model is TRP hylex)

i have an unused TRP olive and barb, however unfortunately they have been knocking about in a tray with an old chain and general grime

They aren’t visibly dirty but have been in contact with chain grime and i would like to know if they should be cleaned in a particular way before being installed.

As it happens, without thinking i ran them under tap water so they are now also potentially contaminated with water.

I’ve searched and can’t find any relevant info.


  • Putting the question in a different perspective you are balancing spending a dollar or two at you LBS against a concern over brake failure. A useful mantra with brakes (along with nearly everything safety)- 'If in doubt, chuck it out' - *(the PC version just doesn't have the same ring- 'If in doubt, recycle it' )
    – mattnz
    Commented Jul 18, 2019 at 21:48
  • I don't really think that mild contamination of these very small components of a brake hose are likely to lead to brake failure - if anything potentially sub optimal performance? perhaps I am wrong. LBS don't sell TRPs components and online the olive and barbs are only sold as part of a bleed kit (which I have) or a 10 pack - either would involve generating quite a bit of waste, which is important to me. I also need to complete this job sooner than any delivery would arrive. I appreciate the sentiment of safety but in this instance I don't think it is unreasonable to clean them myself.
    – Rich
    Commented Jul 19, 2019 at 11:37

2 Answers 2


You can't 'contaminate' brass with water. Just give them a clean with isopropyl alcohol to get any dirt or oil off.

  • thanks. I guess I was more thinking that there might be water trapped inside the (very narrow) lumen of the olive by capillary action which could contaminate the oil. I'll wash them in IPA
    – Rich
    Commented Jul 19, 2019 at 11:41

While I'm not sure whether it's going to be an issue if you leave it, it definitely won't be if you clean it just to be safe. Something like disc brake cleaner will clean off any contamination without leaving a residue behind.

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