These cantilever bosses are from a ?1980’s Coventry Eagle bike. They looked as if they were stamped or cut out of sheet metal. The pivots were crimped in and the bases folded into a box shape before brazing onto the frame. Additional braze was added around the pivots at some point, probably at assembly. As you can see from the top photograph one boss had snapped off with the force of braking and the other was cracked and bending. Whilst it probably would be a good idea to remove and totally replace the assembly, I opted to repair the existing ones so it would still match the similar ones on the forks.
The existing pivots were cleaned up and old brass filed off, as were the bases. Unfortunately because the pivots were somehow crimped in the remaining holes they were a loose fit on replacement, but could still rely on a flange at the base for capillary adhesion.
The final result seemed satisfactory and hopefully strong enough.
