I am renovating a bike, I guess it's 10 years old. It has internal gears with pedal brake. And then it has a hand brake in the front, I think it is called "cantilever direct pull". One arm was moving quite smooth, while the other was very stuck, tough not impossible to move by hand.
In the process of removing the arm from the brake boss, something remained on the boss: some kind of brass-looking bushing with a kind of rubber gasket.
The brass part was almost impossible to remove. I tried different things. And only in the end when I took a 60cm pipe wrench was I able to wiggle it off.
I felt victorious until I realized that the power needed to clamp around the bushing was enough to deform the boss itself. So now I have a slightly oval boss, just enough to notice with the naked eye. The internal threading is now too tight, but it is possible to put in the bolts though. The real problem is putting a new brake arm on the bushing. I cant even get in one millimeter onto the boss.
Picture above shows: Bushing stuck on boss
Picture above shows: The other boss, where the bushing easily slid off together with the arm
Picture above shows: After removal of the bushing, the boss is slightly oval
My question is two-fold:
1) How should I have removed the bushing, without damaging the boss.
2) How can I fix the boss now, so that I can put a new brake arm on it?