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  1. #1
    gnar, brah
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    Pinhole in Magura Reservoir Cap

    I have a set of 2007 Magura Louise BAT brakes, which served me well for a season of daily lift-serviced downhill riding, and a couple of races. At the beginning of this last season, the rear brake was pathetic in performance, and upon examination, had a small pinhole in the plastic reservoir cap. I tried to source a new cap thru my LBS, but it was taking forever, and I ride everyday...so I just ordered a set of Hayes Stroker Aces (which I love).

    Now, I am wanting to through the old Magura brakes on another bike, and was thinking about ordering a new cap. My question is if it would be possible to patch up the hole in the cap with some sort of compound, and save a little money. I would assume that the mineral oil is less corrosive than DOT fluid, but are there any epoxies or other compounds that would hold up, or should I just order a new cap through chain reaction?

    Thanks!
    Trestle Bike Park

  2. #2
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    Where is the hole? Bear in mind that the reservoir caps of virtually all hydraulic brakes have a small hole in them, and there's a good reason. That hole is called a breather hole/vent. It's what allows the bladder to expand and contract, and hence allow fluid to move in and out of the reservoir as the brake needs, like as the pads wear or as the fluid heats up and expands.
    You are not what you own.

  3. #3
    gnar, brah
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    Quote Originally Posted by juancancook
    Where is the hole? Bear in mind that the reservoir caps of virtually all hydraulic brakes have a small hole in them, and there's a good reason. That hole is called a breather hole/vent. It's what allows the bladder to expand and contract, and hence allow fluid to move in and out of the reservoir as the brake needs, like as the pads wear or as the fluid heats up and expands.
    It's right above the second "i" in "Mineral Oil", which is stamped onto the cap. There is no similar hole on the other brake, and every time the lever is actuated, oil seeps out of the hole, until there is not enough fluid to generate any noticeable braking action at the caliper.

    Keep in mind these brakes were on a bike park/downhill bike that is ridden hard and crashed (relatively) frequently. It is completely conceivable that the lever body could have sustained damage somewhere along the way, resulting in this pinhole. Although I have no idea when this could have happened, as it seems to have occurred in the off-season.

    I attached a photo of the reservoir cover, although this is the underside. As you can see, it has no breather vents/
    Attached Images Attached Images
    Trestle Bike Park

  4. #4
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    How much is a new cap? Will it break you to get one? If not, then order it up. If it will (no judgment here) then perhaps try filling the hole with some superglue (from both ways) and or heat the plastic some with a lighter and see if that will get it closed up.

  5. #5
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    Does both (left and right) reservoirs have the pinhole? If so, it's suppose to be there as a breather as mentioned. Chances are the diaphragm is leaking.

  6. #6
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    whats that?
    Last edited by FLMike; 05-31-2010 at 01:11 PM.

  7. #7
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    Dust speck?

  8. #8
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    Call Magura direct. Their customer service is awesome and will get you fixed up if there is a problem.

  9. #9
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    There shouldnt be any fluid on the side closest to the cap.It should be dry.

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