Quote:
Originally Posted by Popcorn
When I was spannering back in the 80s you could buy abrasive pads which cleaned the discs up a treat don't seem to be able to buy them now  |
Abrasive pads were a consequence of asbestos being removed from brake pads. While not great for ones lungs, asbestos was a fantastic material for friction materials, conducting heat away from the disc.
When the various materials initially used as asbestos substitutes worked from a friction point of view, they weren’t great at heat transfer so discs warped, brake judder ensued and so abrasive pads were introduced to machine the disc true again. And discs lasted about as quarter as long as before.
Friction materials evolved to be less abrasive, but there’s still an element of machining going on with associated shortened disc lives.