If they are pulsating like a poor mans ABS it's likely pad crud buildup. Take them to someone you know with a brake lathe and have him hit them with a disc hone.
See the piccys of the setup I made as mine pulsated quite badly. They work great now. I powered the drill press table as well as spinning the hone for a nice even patern.
If you take a micrometer to them you'll likely find that they are thinner near the periphery and thicker towards the inside. This coning wear is typical disc wear. As others said, don't grind them. Try the rotor hone thing first before you replace them. You can get the hone from an auto parts store for $40.
02 998 la strega bella
Last edited by Slower than you; Apr 11th, 2007 at 8:58 pm.