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Replacing pivot bolt on Shimano Sora caliper brakes

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Replacing pivot bolt on Shimano Sora caliper brakes

Old 02-19-24, 11:29 AM
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Replacing pivot bolt on Shimano Sora caliper brakes

Hi all, first time posting. I've lurked for years and have found answers to a ton of questions, but can't seem to find a discussion on one specific thing. I have a 1980s Peugeot Elan—I believe from scouring old catalogs it's from 1987. It's a low-end model (Carbolite+ frame). I bought it about 12 years ago in London for around 100 pounds. I've long since bought a few additional bikes, but this one has sentimental value so I want to keep it around but also give it a purpose my other bikes don't cover, so I've decided to convert it to a single-speed just for daily riding around the neighborhood. Because it's not a high-end model and already has some new parts on it (different wheels, new cassette, new pedals and seat, etc.), I don't have any special desire to keep the components vintage—just want a simple, reliable, and fun bike that encourages me to take it out instead of the others from time to time. I bought a pair of Shimano Sora dual-pivot brakes for it, which are set up for a recessed nut. After reading here and elsewhere, I decided to use the front brake as the rear and I ordered a Jtek 70mm replacement bolt to put into the rear brake so I can use it on the front. Seems like an easy solution, but when I tried to remove the original pivot bolt, I had no luck. I could get it to turn maybe a quarter turn and then it stopped. Because I was impatient, I went for more leverage instead of stopping and thinking it through, and I pretty quickly stripped the bolt with an allen wrench. I then realized that the fact I could move it partway but no more probably meant something is securing it and noticed a little screw on the caliper. I suspect that needs to be removed (or just loosened?). Because I also bought Sora brake levers and I think it would look better if the brakes and levers match, I'd like to try again with another Sora, but don't want to waste the money if I'm wrong. So I have two questions I'm really hoping somebody can help me out with: (1) Is it in fact possible to remove the pivot bolt from Sora brakes? And (2) Am I right about that little screw being the key to removing it or am I way off?
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Old 02-19-24, 01:19 PM
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Yes, there should be small allen grub screw in the underside of the caliper, right above where the tire would be when mounted (on the short pivot arm). This must be loosened to remove the main bolt (axle). If you loosened the bolt with the screw in, it may have damaged the bolt. But that is probably fine if you are replacing with a longer bolt.

The main bolt varies between different caliper models. The threading in the middle of the bolt can vary in location a little based on the caliper that it is intended for. Hopefully you got the correct version.

When trying to re-install the main spring. Loosen the screw on the top of the lever that is used for centering the caliper. This is the screw that you use during installation to center the brake to the rim.

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Old 02-19-24, 03:12 PM
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Thanks, KCT1986. Exactly what I needed. I managed to loosen the grub screw and it all makes sense. Unfortunately I completely stripped the pivot bolt, though. I'm going to keep at it and see if I can work out a way to get it out, but if not it'll go on the parts box and might be useful for a future project. At least now I can take a more intelligent approach if I pick up a new Sora brake.
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Old 02-19-24, 04:05 PM
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It is worth mentioning that reassembly of a dual pivot caliper and getting the tension correct on the pivots can be a major PITA. Just like a hub, the goal is to get the pivots as loose enough to pivot freely while also having little to no play in them. Worry about getting the center pivot adjusted first, then do the other pivot second. Sometimes the center pivot can tighten up slightly when the caliper is mounted to the bike, so make sure it still moves ok while mounted before messing with the other pivot. Make sure to tighten the set screws once the each pivot is adjusted. Once that is done it is time to get the spring tucked into place, do it while the caliper is mounted to the bike. A flathead screwdriver can be used to push it in place, but something with a concave surface will make it easier and safer. Make sure all fingers and other body parts are not positioned in the way of the spring if it slips loose, it can easily damage any flesh it comes in contact with.

Good luck!
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Old 02-19-24, 04:22 PM
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Thanks Arrowana!
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Old 02-19-24, 04:54 PM
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IIRC Most dual pivot Shimano calipers have a threaded portion, that is the section that engages the stationary "backing plate", that is larger than that of the recessed nut's portion. So one should be able to grip the center/mounting bolt with a pliers/ViseGrip on the portion that is hidden by the frame and has the nut's threading, turn the mounting bolt till it disengages with the plate's threads and then just slide the bolt out without doing any damage to the plate's threads. Andy
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