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Brake Interrupter causing brakes to rub?

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Brake Interrupter causing brakes to rub?

Old 09-28-13, 10:05 PM
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Brake Interrupter causing brakes to rub?

Hey all,
I have a quick question. I have a bike that has brake interrupters (2nd set of brake levers on the tops of the bars). When I pull the brake using the main brake levers, the pads will spring back just fine, but when I use the interrupter, they don't spring back as well as they should. The brake itself has had it's pivots cleaned and lubed.

When I squeeze the interrupter, it'll just be a little "loose" after I let it go (there is play in the lever.) The if I squeeze the main lever it'll pull the interrupter "tight" and reset the brakes so they don't rub anymore.

What could be causing this problem? Do the cables need lubed? I lubed the pivots on the levers as well.

For the record, this isn't my bike, and the person's bike it is does not want to remove the interrupters.
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Old 09-28-13, 10:10 PM
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Could be a tight pivot in the intermediate lever, or possibly a cable friction problem that happens when the intermediate lever bends the wire or housing.

I'd start by disconnecting the cable from the brake and feel how much force it needs to pull back, when either lever is used. Then, I'd work back from there, checking cable friction and lever pivot friction.
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Old 09-28-13, 10:41 PM
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I have seen where the cables leave the cross brakes to the cable stops on the frame and the cable has an extremely tight curve. I ended up routing one of my brake cables OVER the handlebars instead of under once it left the cross brake fitting. Works smoother even though it looks odd.

So I'm thinking that when you pull the cross brake lever, it causes the cable to make an even tighter curve which causes the friction.

Using the main brake lever doesn't cause that same friction because the cable runs are staying straighter.
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Old 09-28-13, 10:56 PM
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the cable runs through un-interrupted , it's the housing that is .

were the cut ends of the housing ground off flat and free of burrs ?
no? that may be dragging.

Die drawn (whole spool, surface is slicked after they were made), cables are a big improvement.

maybe the return springs in the caliper, and the primary lever are weak? 'light action'..

Last edited by fietsbob; 09-29-13 at 08:22 AM.
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Old 09-29-13, 07:01 AM
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Yeah. The regular brake levers work by pulling on the cable. The interrupters work by pushing on the housing. As mentioned, if the interrupter pivots are dragging or there's any binding preventing the housing from moving and returning freely, that could cause the problem.
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Old 09-29-13, 08:00 AM
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"The interrupters work by pushing on the housing. As mentioned, if the interrupter pivots are dragging or there's any binding preventing the housing from moving and returning freely, that could cause the problem."

The section coming out of the interrupter lever and going towards the brake must be fully free to move and cannot be impeded from moving by being wrapped to the bar or otherwise attached to anything. Is your housing tie-wrapped to or rubbing against anything such as another brake or shift cable?
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Old 09-30-13, 08:34 AM
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IMO fitting interrupters well is quite a tricky operation.

If the bars have cable grooves you may need to position the levers in a less favourable position to straighten the cable run.

And it couldn't hurt to optimise the length of the housing - usually as short as possible without introducing any sharp bends and allowing full movement of the bars.

While you're at it, throw a couple of drops of oil in the housing.

And if the housing isn't lined, there's your problem; bin it.
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