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  1. #1
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    New question here. Swapping brake hoses - DOT fluid to mineral oil okay?

    I am looking to upgrade my old Juicy 5s to some new Shimano XT M785s. I have a nice set of Jagwire hose that I've been using on my Juicy 5s for the last 2 years. Here's my question:

    Will the hoses be okay to swap from the DOT fluid to the mineral oil for the Shimanos? Obviously, I would have to clean the hoses well and buy a new fitting kit from Jagwire. I guess my main concern is getting the hoses clean enough from the DOT fluid to make the swap.

    Anyone have any experience with this sort of thing?

    Thanks!
    - KERSH -

  2. #2
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    no experience with the diff fluid types. i have changed hoses due to color choice with great success on my J 5's and hayes strokers. whats the reason for changing fluids??

  3. #3
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    I can't see any reason you couldn't flush out the old fluid with some new stuff. Might not be the most cost effective situation, but I can't see why it wouldn't work.

    NV - Shimano uses mineral oil, not DOT fluids like Hayes and Avid.

  4. #4
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    Quote Originally Posted by scottap2003 View Post
    NV - Shimano uses mineral oil, not DOT fluids like Hayes and Avid.
    ahhh shows how little i know of them.

  5. #5
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    Quote Originally Posted by scottap2003 View Post
    Might not be the most cost effective situation, but I can't see why it wouldn't work.
    I have the matching red hoses from Jagwire for my derailleur cables and my brake hoses. Plus, the cables are already cut to the correct length. I think the fitting kit from Jagwire is just over $15 so it shouldn't be too much extra.

    You're saying to flush out the lines with mineral oil? Does water affect mineral oil like it does DOT fluid? I thought about running water through them, then spraying them out with the air compressor, then letting them dry for a day or two. I just don't know if that would hurt anything though.
    - KERSH -

  6. #6
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    I would just pull the cable off, spray brake cleaner down the cables then blow them out with air. The brake cleaner will evaporate without any residue. Then put them on the new caliper/lever setup and fill and bleed the system.

  7. #7
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    Quote Originally Posted by TJay74 View Post
    I would just pull the cable off, spray brake cleaner down the cables then blow them out with air. The brake cleaner will evaporate without any residue. Then put them on the new caliper/lever setup and fill and bleed the system.
    brake cleaner will do the deed for sure. i also thought about alcohol as a 1st step.

  8. #8
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    Yeah, Shimano is always saying to use isopropyl alcohol to clean everything, so I guess that'd be a cheap way to clean em out. Any water in any hydro system is bad. It might not react with the fluid like it does with DOT, but it still lowers the boiling point of the fluid. Your idea of blowing them out and all sounds like it could work. I'd still run some mineral oil through them a bit before putting it all together though.

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