I would strongly advise against using a punch on the spring. I was taught this in my early days as a wrench, but it can break through the chrome plating on the spring, resulting in rust marks later, and it takes some of the tension off the spring. Doing this enough times can reduce spring tension too much. The problem with centering the Campy brakes can come from the star washers. They make little indentations in the mating surfaces that make it hard to move the brake a very small amount, as the star washer tends to bring everything back to the origal position when tightened.
First thing is to make sure the caliper pivot is lubed (take the lock and center nuts off, clean and apply light grease), then adjust the tension on the arms without the cable attached, making sure there is not clearance and also no drag. Attach the cable, make sure it has sufficient slack in the casing, so it doesn't tend to pull the caliper to one side or the other, and adjust the pad to rim clearance after making sure the rim is centered between the fork blades or seat stays. If you need to recenter the brake, loosen the mounting nut, position the center bolt while holding it with a 13 mm cone wrench (or suitable alternative) and retighten while holding it in place. This will usually work. If it doesn't, CAREFULLY detach the spring from the side of caliper closest to the rim, using a pair of non-serrated needlenose pliers (such as jewelers use), and pull the spring away from the rim, increasing its tension slightly. Rehook the spring and chack clearance again. Be sure to snap the lever a couple of times, then let it return normally. If the caliper is still not centered, but its centering has changed, return to the loosening the mounting nut step and try again.
In general, if someone comes toward your bike with a hammer--RUN.
Why did Campy design the calipers with so much more spring tension? Because bike racers were real men in those days, not wusses who couldn't trim their shifts or flip their toeclips. And they didn't use those plastic lined cable casings, either. It wasn't to make the levers harder to squeeze to keep riders from making abrupt speed changes in the peleton. That was the excuse for using a pad material with such a low friction coefficient (at least that was the line we used when a white-knuckled customer returned after the first ride on his new Raleigh Pro). Scott-Mathauser took a lot of the excitement out of descents on full-Campy bikes.
Steve Barner, who owns about 50 different kinds of hammers, Bolton, Vermont
> From: Paulie Davis <paulieflt@email.com>
> To: <Classicrendezvous@bikelist.org>
> Sent: Thursday, June 19, 2003 1:21 PM
> Subject: [CR]more [newbie] brake caliper tension - off to side?
>
>
> > Hi all,
> >
> > I keep running into what must be a classic problem with my various Campy
> sidepull brakes -- difficulty in centering. One book I have says the
spring
> needs to be retensioned with use of a punch somehow, but it seems more
like
> a question of centering the brake caliper body and re-tightening the nut.
> However at the moment, even when I do that, it doesn't work for more than
> one or two uses of the brake lever.
> >
> > Can somebody point me to a good discussion of this problem in a book or
> online? Sheldon Brown covers cantilevers, but I can't find something on
his
> great site that addresses my problem.
> >
> > Paulie "seemingly forever newbie" Davis
> > In foggy (rainy?) Los Angeles, CA