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stupid question about dot

Discussion in 'Downhill & Freeride' started by dhkid, Oct 5, 2005.

  1. dhkid

    dhkid Turbo Monkey

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    why do you have to change dot fluid when it get all merky coz of boiling? mine gets merky after about 3 weeks of everyday riding. gets annoying to change them all the time. oh yea, is there someone who can proove that minerall oil works in dot systems with no problem? besides saying that someone you know has ran them for 3 years with no problems ect.
     
    #1 -   Oct 5, 2005

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  2. 8it

    8it Chimp

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    Something might be wrong with your set-up. You shouldn't be going through that much hydro fluid that frequently. What kind of brakes are you using, are you using the right kind of fluid for your set-up? Are your brakes loosing power? Try to provide a little more details and maybe one of the monkeys can help you figure it out or you can take a trip to your local bike shop. Good luck
     
    #2 -   Oct 5, 2005
  3. dhkid

    dhkid Turbo Monkey

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    eh, every detail? here it goes. my brakes are hope minis. 9 in rotor in front, 5 in the rear. stock mini pads. power suck really bad, the brake has been bled over and over agian, same ****. and the feel is solid so air in the system is out of the question. about the pads, i can get them to work really nicely if i sand them down to make them rough but they hardly last a ride. and then the power is really ****ty agian. about the fluid boiling all the time, i live on a hill, 2700 ft ASL, so everday i go to work by bike, the road down is 5.1 km, i dont drag al the way down, but just at the last km, my brakes boil or are pretty close to boiling. so i dont think there is anyway aorund my problems. oh yea, about the power, i am getting new pads, galfer ones. so if it still suck, new brakes!!!! oh yea, my trip to the LBS is every day coz i work there.
     
    #3 -   Oct 5, 2005
  4. Biscuit

    Biscuit Turbo Monkey

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    What fluid are you using? Specifically?

    I had a very similar problem with my hopes a few years ago that made me hate them. Turns out there is a big difference between dot 5 and dot 5.1 fluid. One is glycon based and one is silicon based (I think).

    Basically, the wrong fluid will gradually eat up your seals, causing air leakage and contamination. It gets worse and worse till your brakes litteraly don't last a ride. You could try sending them back to hope for new seals, their customer service is top-notch.

    Another possibility is whatever fluid your using could be contaminated. Brake fluid readily absorbs water from the atmosphere. If you've left your fluid bottle open, it will get water in it, and boil extremely easily.

    As for using mineral oil, whats the point? The fluid that hope recommended to me works great, is cheap, and available at any auto-shop. It's a synthetic, in a gold bottle, I believe made by valvoline (not positive though). Try that.

    And, check your hose for kinks. Even if it appears fine on the outside, a kink can cause a breakage on the inside, leading to bad brakes.
     
    #4 -   Oct 5, 2005
  5. dhkid

    dhkid Turbo Monkey

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    i just bought a botol of motul 5.1 brake fluid, gonna flush out the system when i can find a hose to fit over nipple. might contact them for that rebuild. see what happens.
     
    #5 -   Oct 6, 2005
  6. mack

    mack Turbo Monkey

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    I have been running mineral oil in my grimeca system 8 brake since february without any problems at all. Not that it works any better or anything, just that i have a shimano lever (mineral oil) and grimeca rear caliper (DOT).

    I left some DOT fluid in an open bottle for about half a year now, and its all congealed at the bottom. Kinda strange.
     
    #6 -   Oct 6, 2005
  7. Gfreak

    Gfreak Monkey

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    Are your brakes the old Minies or are they the newer Mono Minies? If they are the old minies I had the same problem but I was able to fix them. The problem arises from the Minies not having a bolt to secure the upper half of the calipers (near where the brake line is connected). In most cases if you look at your caliper closely while holding onto the brake you can see the caliper halves separating, thus letting air into the system. To fix this all you need to do is buy a couple of small hose clamps from Auto Zone and install it around the upper portion of the caliper and tighten them down as much as possible. If your worried about looks, Speed Goat Cycles used to sell a machined bracket for the hope minies. Problem solved.

    If your brake is a Mono Mini I don't know what to tell you.
     
    #7 -   Oct 6, 2005
  8. snoopz666

    snoopz666 Monkey

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    this is because bake fluid absorbes water over time, this is why you should only buy small bottles and not use old fluid.


    k this is x posed from a thread i repiled to a while ago about DOT fluid

    so next time you decide to bleed them try 5.1 it should help your braking performance alot. especially since your getting the new pads.
     
    #8 -   Oct 6, 2005
  9. dhkid

    dhkid Turbo Monkey

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    they are the old minis, and i am using dot 4 right now. i dont think i have problems with air getting in the system. but that might explane why the brake fuild dissaperes. has anyone ever had brake fuild come out of the calipers insead of air going in?
     
    #9 -   Oct 7, 2005
  10. LOOnatic

    LOOnatic Turbo Monkey

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    If fluid was coming out then it would be wet on your caliper,pads,rotor,etc.....
    You would notice that
     
  11. dante

    dante Unabomber

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    BUY HAYES!




    (sorry, couldn't resist) :blah:
     
  12. Biscuit

    Biscuit Turbo Monkey

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    Actually yes! On a pair of hopes I had!

    What happened to me, was I had to buy a new 1/2 caliper to transfer it from a intl std to a boxxer mount. When putting on the new 1/2 caliper, I didn't notice the tiny little o-ring that goes around the "fluid hole" in a tiny little detent.

    If that o-ring is either worn out or missing, your caliper will leak.
     
  13. snoopz666

    snoopz666 Monkey

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    well if you want something new you could buy my hayes front brake... ;)
     
  14. dhkid

    dhkid Turbo Monkey

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    just changed the fuild, see how the ride goes tomorrow. i am thinking about mono minis, or m4s or if i give up on hopes, juicys.
     
  15. Brian HCM#1

    Brian HCM#1 MMMMMMMMM BEER!!!!!!!!!!

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    Don't use DOT 5 in Hopes. Only use a high quality DOT 3-4 or 5.1. As mentioned above the older minis did sometimes have an issue with leakage at the caliper from braking forces.
     
  16. dhkid

    dhkid Turbo Monkey

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    i just used motul 5.1, thats alright rite?
     
  17. Brian HCM#1

    Brian HCM#1 MMMMMMMMM BEER!!!!!!!!!!

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    Yep, that's the stuff I recommed for Hopes.
     
  18. dhkid

    dhkid Turbo Monkey

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    while on this topic, which brake pads worked best for you?
     
  19. DirtyMike

    DirtyMike Turbo Fluffer

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    Ok this is a question for me........ 2 degrees one automtive one deisel tech...
    Ok DoT 3 DOT4 and DoT 5.1 are all glycol based <Master certed AUto Tech Btw i answer this question a couple times a week> Mineral oil will destroy not only your brake system but your warranty. DoT5 is a synthetic based fluid and is usually purple. WIll suually find i on high end luxuray vehicle high Xtra high performance vehicles and Crotch rockets. Hope Mini's and Hayes recomend using DoT 4 or better.... DOT 3 will break down and Boil Way to easy. NOw as far as what your talking about Have you called Hope yet?.. they had a few warranty issues with the Mini's. i have gotten more than a few set totally replaced for free<Works at Bike shop in off time> Oh yeah teh DoT3 DoT4 and DoT5.1 will eat the paint/PC/anyting right down to the metal someimes you wont see it till you wash it. As far as teh Pads needing to be sanded try a different brand or maybe a different compound might get a beter result... i knwo alot liek Kol stops See is someone offers a Sintered Pad for the ones you are running. little harder on teh rotors But they wont harden up like the factory pads sounds like your on teh right track though with the 5.1 very high Boiling point but remember with anything glycol based it starts absorbign water as soon as you open it right from the air if the bottle has been open and not used up in a week Throw it out even with the cap on it has already absorbed enough water to lower the boiling point dramatically
    All three of the DoT gylcol based are Very Prone to this no matter how high of a quality fluid it is.. Its just the nature of the fluid type... Call hope though tell them whats happeneing Might get a Free set of brakes
    ________
    The Cliff Condos Cosy Beach
     
    #19 -   Oct 9, 2005
    Last edited: Aug 25, 2011
  20. Brian HCM#1

    Brian HCM#1 MMMMMMMMM BEER!!!!!!!!!!

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    I have used Hope organic, sinthered, EBC greens and reds. I like the EBC's.
     
  21. dhkid

    dhkid Turbo Monkey

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    ok, its been about a month since i changed my brake fuild. good news is that it doesn't fade anymore and the caliper doesn't leak oil. bad news is that the oil has turned merky again and the brakes feel a bit squishy. so whats wrong now? :(