Hayes Nine cup expand- Mtbr.com
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  1. #1
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    Hayes Nine cup expand

    I Found out why my Hayes Nine rear Lever stuck.
    The first cup in master cylinder has expanded .The outer one I mean .The one which seals the system from outside.

    But why has it expanded its outer diameter is 0.7 mm wider4 than the one in my front lever .So it moves in the master cylinder’s bore with lots of friction and force and get stuck after some time . I used a low profile Dot 3 fluid in it and it was in the system for several months could the cause been that ?

    What ever the **** cause is I have to do one thing fix it and I have thinked about some solutions
    1: File the outer part of the master cylinder’s bore a little till its bore gets 0.7 mm wider in that section

    2: Sand paper on the cup its self to take some material off it . But this makes tha side wall of the cup a little thinner and maybe under hydraulic pressure it would fail and let fluid pass .

    3 : Buy a friends Hayes mag used lever ( its broken from the bar clamp section ) and use its cups .Also save its other parts for future .

    4 : Dip the cup in high quality fluid and hope I would show some diameter decrease .

    As soon as I noticed this function .I opened the whole system and clean whashed all parts .Tommorow I have to buy a high quality Dot 3 fluid and rebuild the whole systems then wait what happens . Hope the problem solves and if not im waiting for your advise
    Thanks a lot.

    By the way today's point Dont cheap on parts or wait for a big spend.
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  2. #2
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    Dont use dot 3, it is lower quality, use dot 4, I wont use dot 3 in any of my brakes.

  3. #3
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    By chance did you...

    Use loctite on the adjuster bushing on the lever blade or lbe the lever pivot with a lube of some kind? If so it might have reacted with the seal material. FYI those seals are not available separately, you'll need a whole new MC piston.

    R

  4. #4
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    Well done I fixed it . I tore the cups while working on them and got out of confusion to fix them or buy new ones.

    First I thought if I file the M.C. ‘s bore the new cups would no more stand in it. So I stated to file the rubber cups with a drill mounted file and it tore the cup.

    Now I have to pay 25 bucks for a new set of cups.
    By the way what do you think about Avid Juicy 3 ‘s I can buy a new set of them for 235 $ here I would sell the 180 mm rotors for 60 $ and use them on my Hayes 8”s . How are they for DH /FR?

  5. #5
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    they arent bad, but not the best

  6. #6
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    I got the Juicy's and ended the dilema .
    lessons ( mesure twice cut once)
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  7. #7
    Disco-Superfly
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    you're not supposed to take the seals of the MC pistons... just get new pistons, mine cost me $0.

    w/e you did the right thing and got juicies.. lol
    Jake
    Yeti 303 WC 25th

    Quote Originally Posted by Dwight Moody
    Didn't you read the sticker on that shock? It said not to do whatever you did.

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