Brucey wrote:I am not an advocate of using magnets as pad retainers on disc brakes that will see a lot of heat for that exact reason. There are very few magnetic materials that will remain strong permanent magnets at temperatures much about 150C. You can get to 150C quite easily.
I would have thought this not accurate. There are strong permanent magnet materials that have a Curie temperature of many, many hundreds of °C. These can still lose their magnetism below this temperature in a processes analogous to creep, however 150°C is roughly the no-creep limit only for the best neodymium magnets, and even then brakes don't spend a long proportion of their life time hot. If a manufacturer were prepared to accept second-best magnet material, there would be no problem with creep at all.