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  1. #1
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    DOT 5.... ooops.

    So I just replaced the hose on my rear Juicy 7. I was out of brake fluid, so I went down to Autozone to pick up some brake fluid. I grabbed a bottle of DOT 5, not thinking that there would be a significant difference between DOT 5 and Dot 5.1....

    Apparently there is. DOT 5 is silicone based, and not compatible with DOT 3, 4 or 5.1. They do not mix (oil and water style). So I guess I need to clear out the system and re-bleed it. Anything about this that I should know? Have I damaged something?

  2. #2
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    The LBS did this to my brakes once. They had to completely replace the brakes. I don't know if you can get all the old fluid out but if you can it probably means a complete tear down and cleaning.

  3. #3
    007
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    Someone with more experience will comment for sure, but I think your brakes are toast. I've read that the DOT 5 fluid will destroy the seals.

  4. #4
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    taking it all apart to inspect the seals wouldnt hurt. its hard to say if your seals are shot but itll be easy to see when you bleed it properly.

  5. #5
    007
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    "Using DOT 5 or mineral oil in your Hope brake will damage the rubber seals and require a full strip-down and cleaning of all brake components. Unless you flush and clean the system straight away, chances are that a seal change will be required."

    Hope Brakes Bleeding Mountain Bike Maintenance

  6. #6
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    It does take time for the fluid to penetrate the elastomers in the system...certainly more than a day or so, for the full effect so drain it right away then clean it up with some water flush, then the correct brake fluid flush...

    Then fill bleed and try....gonna have to go there anyway.

  7. #7
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    If it were me, I would take everything apart. Possibly replace the seals and pistons in the calipers if required, maybe new lines and have a good look at the levers.

    Should be cheaper than new brakes and could well save the J7's.

    In any case, get as much of the fluid out as possible as quickly as possible.

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