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  1. #1
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    Shimano Brake Caliper Cam Removal?

    My front brake's cam doesn't work anymore. It is seized up, so that when you rotate the lever, the cable bolt rotates too. If I hold the cable bolt with an allen key, then I can rotate it, so it's not 100% seized.

    I'm trying to take it apart, clean it and reassemble with some fresh grease. However, it's not coming apart with gentle force. Assemblies 19 and 20 come off fine.

    From the exploded diagram, it looks like I can push on the thread on the frontside where the small screw was located, and that should push the rear assembly out. I tried with modest force with a screwdriver on the back too, but it's pretty stuck (I guess the seized running surfaces for rotation are also the same surfaces that need to slide on each other to pull it apart).

    I've not pulled one apart for a while, so don't remember if there was a trick. My google ability is also not providing answers.

    Any good trick to use? My next try will probably be a longer bolt in the front and pushing with a vice to press the two pieces apart. I just don't want to jump in their with more force and do some damage. This brake was an eBay purchase a few years ago for my fixie, and I don't want to spend more money on the bike (but I do want a working front quick release).

    Thanks.

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  2. #2
    wim
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    I had a similar problem with an older Campy Record brake recently when the cable pinch bolt assembly would no longer rotate. After dribbling thin lube into the pivot area and waiting for a few hours, still no go. What finally did it was some boiling water into which I immersed that part of the caliper for about a minute. Voila, it broke free. After lubing it again and about 100 or so left-and-right rotations using pliers, to gain some leverage, the assembly rotated as freely as when it was new.

    If you want to give this a shot, I'd put bolt and washer 19 back on. There's really no point in pulling any of this apart. All you really want in there is a thin lube, not grease.
    Last edited by wim; 05-29-2013 at 04:24 AM.

  3. #3
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    Quote Originally Posted by StillKeen View Post
    My front brake's cam doesn't work anymore. It is seized up, so that when you rotate the lever, the cable bolt rotates too. If I hold the cable bolt with an allen key, then I can rotate it, so it's not 100% seized.
    No need to take it apart. Dribble some oil on it from every direction and "work it, work it, work it" back and forth. The oil will turn black (probably) and the mechanism will start functioning smoothly. If you're really anal about it, wipe off the excess oil and repeat the process. If you use a heavier oil on the second go (like 90w gear lube) then the lube job will last longer. It's not a bad idea to do this treatment once a year even if everything is working fine. Think of it as preventative maintenance.

  4. #4
    wim
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    Quote Originally Posted by Kerry Irons View Post
    Dribble some oil on it from every direction and "work it, work it, work it" back and forth.
    If this is possible, sure. But with my Campy brake mentioned above, there was no way to work it. The parts were stuck as if they had been welded together. The cause, if anyone is interested, was years of sweat and no cleaning ever.

  5. #5
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    Thanks. I will use some oil, but I still want to open it up to clean it out.

    Thanks

  6. #6
    Matnlely Dregaend
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    Quote Originally Posted by wim View Post
    If this is possible, sure. But with my Campy brake mentioned above, there was no way to work it. The parts were stuck as if they had been welded together. The cause, if anyone is interested, was years of sweat and no cleaning ever.
    This is the reason I stopped using Campy brakes. The part that fits through the brake arm and is held on with a C-clip is coated steel and will easily rust (even on Record brakes labeled titanium hardware). If you get sweat on the part it will wick into the covered section and corrode in a matter of weeks. The best solution I have found is coat the part liberally in anti-seize. This requires removal of the c-clip .
    "I haven't @#&$ed like that since I was an altar boy." - Hank Moody
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  7. #7
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    Quote Originally Posted by DrSmile View Post
    This is the reason I stopped using Campy brakes. The part that fits through the brake arm and is held on with a C-clip is coated steel and will easily rust (even on Record brakes labeled titanium hardware). If you get sweat on the part it will wick into the covered section and corrode in a matter of weeks. The best solution I have found is coat the part liberally in anti-seize. This requires removal of the c-clip .
    Strange. My Campy brakes are 14 years old with 145K miles on them. No rust. Sometimes the cam gets stiff after a season of riding so I dribble oil in there, work it back and forth a lot, and it's all good. Never had one rust.

  8. #8
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    I've tried with light oil (triflow), but its still very still. I'm going to proceed with pressing it apart.

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