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  1. #1
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    Cleaning pistons

    To keep the pistons in my XTR calipers from getting stuck in an extended position and causing rub/drag, I regularly do what seems to be the consensus service: clean, lube, work pistons in and out, clean, lube, and so on...until they extend and retract well.

    In doing this, I notice that in working the pistons in and out (I use a plastic tire iron as a lever), a piston might get crooked-- if I push on the edge of the piston, instead of in the middle, to force it back into the caliper body.

    I'm wondering 1) is that bad, and 2) how best to avoid it?

    I'm thinking I might be damaging the seals around the pistons...

  2. #2
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    Forcing a piston back into the bore when it's crooked could damage the caliper, seal or piston. You more or less answered your own question - just press on the center of the piston. Pistons should always move smoothly and with only firm pressure applied. If you're having to crank down, then you need to check that the piston isn't crooked.
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  3. #3
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    Quote Originally Posted by SteveUK
    Forcing a piston back into the bore when it's crooked could damage the caliper, seal or piston. You more or less answered your own question - just press on the center of the piston. Pistons should always move smoothly and with only firm pressure applied. If you're having to crank down, then you need to check that the piston isn't crooked.
    I guess I wasn't clear...it isn't that the piston is crooked to start with, and therefore stuck. Sometimes it is hard to apply pressure in the center of the piston (e.g. when both are extended far to clean). When the edge gets pushed on instead, it sometimes makes the piston crooked (which is easy to straighten out). I'm just wonder how bad that is, and perhaps more importantly, looking for TIPS on a good way to avoid it (beyond: don't push on the sides).

  4. #4
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    Don't extend both pistons at the same time? How's that for a TIP?
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  5. #5
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    Don't extend both pistons at the same time?

    Quote Originally Posted by SteveUK
    Don't extend both pistons at the same time? How's that for a TIP?
    not bad...more?

  6. #6
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    "not bad...more?"

    Don't eat yellow snow.
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