It appears the Universal brakes are cast, not forged. Thus they are brittle, the grain is not aligned correctly. No wonder Mafac felt the need to distinguish their brakes by writing "Dural Forge" on them.
I wonder about putting modern pads on them (not that I plan to do that) - it could be that the increased friction leads to failure, because the brake arms weren't designed for those loads.
--
Jan Heine, Seattle
Editor/Publisher
Vintage Bicycle Quarterly
http://www.mindspring.com/