As edde said, you need to make sure what youve got is working correctly before looking at spunking your hard earned on shiny new pads, discs etc..... Is the 'jumping' feeling only happening when you slam on??? If the ABS is cutting in, the pedal will feel like its jumping against your foot, how are the tyres, and how are the road conditions where you are??? If youre driving around treating youre brakes like a switch (all on or all off) then youre gonna lock up fairly regularly, or cause the ABS to kick in.....