it is my understanding that if you run a car under hard braking and then park it with the pads still really hot, that they can create hardspots. Hardened metal has been changed metallurgically and when the shop tries to turn the drum, the softer material gets trimmed away, but the blade that cuts the drum does not cut the hardspots well.
Regardless, whether turned or not, drums with hardspots will result in grabby brakes as the drum surface surrounding the hardspots wears away while the hardened metal stays and becomes something of a speed bump in the swept surface that the pads jar over repeatedly.
Soooo... If you fail to find a handy replacement from another make that you can get over the counter, you may have to look at used drums. The good news is that hardspots are the exeption and not the rule. A good parts vendor will "spot" this defet and send good ones, but double check anyway.
Back to the Home of the Forward Look Network