Campy 11 skeleton brake action adjustment

[fmradio516]

Howdy; im back! I have a set of well loved brake calipers that I acquired not long ago. The overall feel has been fine, but recently i started putzing with it to try to get left-right arm action equal and i have royally screwed them up. Now when I squeeze the brake, the caliper arms only open up a few millimeters. I have to use one hand on each arm to pull them apart. I tried mostly playing with the middle adjuster with the set screw that the spring goes through. Ive tried turning that adjustment a ton in each direction, which is probably why its screwed up now.This is a chorus brake btw.

Is there any hope to fixing it or should i just buy new brakes? Cable/housing is good.

[Hindmost]

I think you're talking about dual pivot caliper. The 'middle adjuster' is simply for the pivot (not for arm travel) and it sounds like you've tightened this up so that the caliper arms don't move freely.

[fmradio516]

I think you're talking about dual pivot caliper. The 'middle adjuster' is simply for the pivot (not for arm travel) and it sounds like you've tightened this up so that the caliper arms don't move freely.

Yep thats what did it. I guess this works different than much older brake calipers. Used to be able to get a cone wrench onto that adjuster and kinda pivot the arms enough to get equal space on both sides.

Ill need to look again, but I think I already tried loosening it a bunch and it didnt help. Thanks.

[Hindmost]

You can still center the calipers with the thin wrench at the caliper base and the allen nut at the far end of the shaft. Separate from that, set screw in the center needs to be released, the pivot play adjusted, and then retightened. Release the allen nut before you do this. I think...

[fmradio516]

Well yesterday, I loosened up the middle adjuster more than I originally thought I needed to, and now its returning normally. Now the only issue is that only one of the arms is moving. The other is just kinda constantly gliding against the rim. I can push the calipers lightly to make them center again, but as soon as I use the brake, its back to being sideways. Rear bolt is tight.

I saw the teeny adjuster screws on each arm, but after turning them a bit, i realized its not doing much.

[oldpotatoe]

Well yesterday, I loosened up the middle adjuster more than I originally thought I needed to, and now its returning normally. Now the only issue is that only one of the arms is moving. The other is just kinda constantly gliding against the rim. I can push the calipers lightly to make them center again, but as soon as I use the brake, its back to being sideways. Rear bolt is tight.

I saw the teeny adjuster screws on each arm, but after turning them a bit, i realized its not doing much.

Check to see if the spring is about to break.

[Mark McM]

Well yesterday, I loosened up the middle adjuster more than I originally thought I needed to, and now its returning normally. Now the only issue is that only one of the arms is moving. The other is just kinda constantly gliding against the rim. I can push the calipers lightly to make them center again, but as soon as I use the brake, its back to being sideways. Rear bolt is tight.

I saw the teeny adjuster screws on each arm, but after turning them a bit, i realized its not doing much.

Like Hindmost said, the main centering adjusting on dual pivot calipers is just like single pivot calipers - us a thin wrench on the base of the center pivot, and rotate the caliper to adjust. The set screws on the arms are only for minor centering adjustment and/or adjusting the return spring pre-load force.

Unlike with single pivot brakes, the arms of dual pivot brakes do not move independently. To center the arms, you have to rotate the entire caliper.

[Hindmost]

Check to see if the spring is about to break.

Oops, this is incorrect, Mark is right, see below...

This is a real thing, one arm will become very weak compared to the other and the spring part is symmetrical. A crack can develop in the bend leading to the spring coil and can fail pretty quickly. The metalurgists here can explain the spring steel, bending, chrome, etc etc.

You can check this by releasing the spring from the back of the caliper arm and just sort of testing springiness on each side. One side may appear out of alignment.

[Mark McM]

This is a real thing, one arm will become very weak compared to the other and the spring part is symmetrical. A crack can develop in the bend leading to the spring coil and can fail pretty quickly. The metalurgists here can explain the spring steel, bending, chrome, etc etc.

You can check this by releasing the spring from the back of the caliper arm and just sort of testing springiness on each side. One side may appear out of alignment.

This is true for a single pivot brake (like the rear caliper of Campagnolo differential brakes), but not for dual pivot brakes. There is only a single spring on dual pivot brakes. The arms on a dual pivot brake are linked together, so the spring retracts one arm, and then that arm retracts the other arm. A weak spring can not cause the arms to retract unevenly.

[fmradio516]

This is true for a single pivot brake (like the rear caliper of Campagnolo differential brakes), but not for dual pivot brakes. There is only a single spring on dual pivot brakes. The arms on a dual pivot brake are linked together, so the spring retracts one arm, and then that arm retracts the other arm. A weak spring can not cause the arms to retract unevenly.

Do you have any suggestions what would cause it? Its not that they retract unevenly exactly, but when I squeeze the brake, only one arm moves and the other just stays flush against the rim.

[Hindmost]

..but when I squeeze the brake,...the other just stays flush against the rim.

Something is not clear here... So one pad starts out flush against the rim and 'stays flush against the rim'? If so, center the calipers as we have described.

[Mark McM]

Do you have any suggestions what would cause it? Its not that they retract unevenly exactly, but when I squeeze the brake, only one arm moves and the other just stays flush against the rim.

There's a lot of information missing here:

You just describe them as "11spd skeleton brakes". But skeleton brakes included both dual pivot (front brake and non-differential rear brake) and single pivot (differential rear brake). Is it a dual pivot or single pivot brake?

When you say, "I have to use one hand on each arm to pull them apart," does it take any significant force to pull each arm? Do the stay in position once you've pulled them open?

Have you tried tried centering the brakes by rotating the base of the central pivot? Does the base stay in position (not rotate back) when you squeeze the lever?

If you actuate the caliper by directly squeezing the arms together (instead of squeezing the lever to pull the cable), do the arms retract normally?

[giordana93]

you need to start again from scratch. 1st, familiarize yourself with campagnolo doc's (as in rtfm):
https://www.campagnolo.com/media/files/035_37_Technical%20manual%20-%20%20road%20brakes_%20Campagnolo_Rev03_05_18.pdf

see page 7. some models have a traditional centering screw; some have a spring tension screw which acts differently. you need to set either of these in the middle of their range (tighten all the way then back off a few turns) then loosen the mounting bolt, center the brakes manually, tighten down, then microadjust. it sounds to me like you have the spring tension screw set up and have locked out one side.
also, before any adjustements, give a drip of tri-flow to all pivots and spring contact points

[Nomadmax]

A linked video of the problem would go a long way.