February 9th – A puzzle, for sure. Shimano metal sintered disc brake pads for hydraulic brakes: what happens to them that renders them useless beyond recovery?

Usually the rear set, all of a sudden they loose stopping power,  and often become screechy. They are not contaminated with oil, although it feels like it. Deep cleaning in the dishwasher doesn’t work. Ultrasonic cleaner with solvent doesn’t, either. Neither does surface grinding as much as .75mm off the surface.

It’s like they just glaze, and some structural or metallurgical change takes place, and that’s it. Only thing to recover stopping power is new pads. Or using them in the rain; when wet, and only then, do they stop better.

At £20 a set, this is not fun. Anyone any ideas please?