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single pivot brake re-assembly help

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single pivot brake re-assembly help

Old 10-20-13, 04:26 PM
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zrossiter
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single pivot brake re-assembly help

So I have some old parts that I am giving to a friend to replace some of his even older/worse parts.

I have a set of some old dia compe single pivot brakes. One of them has no tension/spring, however.

I took it apart and it seems to have all the pieces (bearings, a spring for each caliper side, etc) but when I put it back together it's still quite, erm, limp.

I could not find anything online for re-assembly, or if it is necessary to tension them somehow. Granted they may be done, I figure I would get some knowledge on the subject before I toss them
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Old 10-20-13, 09:42 PM
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Andrew R Stewart 
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There were a few years in the 1980s that DC caliper springs were limp. We stretched then stronger frequently. But a few things to be aware of. First is pivot friction. It's better to have a slight slop between the arms then too much friction. Second is the orientation of the center bolt and the spring. The Vast majority of single pivot calipers have the spring held on the center bolt above the center. There are a few with the spring's center section located below the bolt's center but their rare. Next up is classic cable friction. Whether from casing routing issues or from internal sources. Last is the lever and it's pivot moving freely. And.
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Old 10-21-13, 10:41 AM
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The spring only needs to be strong enough to open the calipers to the point where the shoes will clear the rim; it does not affect braking performance. Do you have no return action at all from the spring? Have you tried removing it from the caliper and bending it to increase the return action? What model brakes are these? Many Dia-Compe calipers were licensed copies of Weinmann calipers, and many parts are interchangeable.
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