Shudder to thank

PETER Koning, of Hopper Stoppers in Werribee, says this is a problem in EF/EL Falcons. Every disc rotor has a small amount of face run-out. All modern brake calipers have an internal seal design that causes the pads to pull back slightly clear of the disc. When the seals get old and hard, the caliper doesn't retract properly and the pads rub lightly, even when not using the brakes, and take the high spots off the rotor as they go past. This causes disc thickness variation, and that causes your brake pulse. Koning is seeing a lot of EF/EL Falcons and, though the calipers may not appear to be seized, he finds the car often comes back with warped rotors if he only machines the discs and doesn't recondition the calipers as well.