Lift the front of the car and place it on axle stands then take away the roadwheel. Spin the disc to investigate it; with light scoring being the norm, there is too much damage therefore one must be removed and replaced or ground with a qualified engineering service. Measuring the disc thickness Check with a micrometer in various positions. When changing the disc brakes, remove the caliper without disconnection of the hydraulic hose but instead, hold the caliper using a piece of wire attached to the coil spring so that the hose is not strained. Then take out the countersunk cross-head screw, and draw out the brake disc out of the hub. Refitting entails undoing the undoing process making sure that the mating faces of the hub and disc are clean.