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Old 02-01-07, 07:59 PM   #1
kmart
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Stripped brake cable clamp. Can fix?

Wee! I just installed a brand new Cannondale Theta road bike brake caliper (it was cheap but I realize now that was a mistake) and tightened the cable down, probably harder than I should have, but I thought hey this is a front brake, it needs to be tight. Well of course, I stripped something. On the brake caliper where the cable is attached to the clamp, there is a plate with a threaded hole and a screw with a square washer on it. The cable is clamped between the washer and the plate as the screw is tightened down. I actually bent the plate slightly and stripped the threads out of it.

Now, I am wondering if would be OK to fasten the screw to the plate by passing it through the stripped hole and clamping it with a nut on the other site. Has anybody ever tried this?
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Old 02-01-07, 08:09 PM   #2
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Originally Posted by kmart
Wee! I just installed a brand new Cannondale Theta road bike brake caliper (it was cheap but I realize now that was a mistake) and tightened the cable down, probably harder than I should have, but I thought hey this is a front brake, it needs to be tight. Well of course, I stripped something.
Congratulations! This is an essential part of the education of a bicycle mechanic, not a "mistake."

If you never strip anything, it means you're habitually leaving stuff too loose. This is how you learn to judge tightness by feel, something that the mindless slaves of torque wrenches never learn.

Were the threads dry? If so, that's a BIG no-no. That is the most important fastener on the bike, should always be greased or at least oiled.

Quote:
Originally Posted by kmart
On the brake caliper where the cable is attached to the clamp, there is a plate with a threaded hole and a screw with a square washer on it. The cable is clamped between the washer and the plate as the screw is tightened down. I actually bent the plate slightly and stripped the threads out of it.

Now, I am wondering if would be OK to fasten the screw to the plate by passing it through the stripped hole and clamping it with a nut on the other site. Has anybody ever tried this?
Yes, that will be just fine, as long as there are no clearance problems. Most likely it's a standard M5 thread.

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Old 02-01-07, 09:13 PM   #3
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No, I didn't put any oil or grease on it...doh! I think all the metal was alloy, which is why it stripped so easily. Alas, I tried putting in an M5-sized nut and bolt and it doesn't have room to clear.

On the other hand, for the brief moment before everything stripped, I got a few good squeezes out of the brake lever and noticed a bit of flex on the caliper. What a piece of junk...Yea, it was a good learning experience all right. Lesson: buy steel parts where it counts!
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Old 02-02-07, 03:27 AM   #4
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Could try a thread insert repair kit like recoil or helicoil, I have used them on machinery, but they are expensive (here in N.Z)
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Old 02-02-07, 06:27 AM   #5
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Helicoil kits are expensive all over. But they're worth their weight in gold!

+1111eleventy billion!!!11! on what Sheldon said about torque wrench slaves.
I remember the joy I had as a child when I broke my first bolt while tightening it, and dad was standing there too. I find myself within 10% of spec when I check myself against a torque wrench
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Old 02-02-07, 02:06 PM   #6
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What about just tapping the hole for the next larger diameter bolt?
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Old 02-02-07, 06:17 PM   #7
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Quote:
Originally Posted by Sheldon Brown
Congratulations! This is an essential part of the education of a bicycle mechanic, not a "mistake."

If you never strip anything, it means you're habitually leaving stuff too loose. This is how you learn to judge tightness by feel, something that the mindless slaves of torque wrenches never learn.
Normally I find your advice very good but I have to take exception to this one. It's like saying if a surgeon doesn't cut the wrong thing once in a while he'll never learn good surgery. Us "mindless slaves of torque wrenches" don't break stuff and we don't leave it too loose.
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Old 02-02-07, 06:20 PM   #8
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Interesting. Ask your surgon about malpractice insurance.
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