Disc refacing is not a given whenever you change
Brake Pads, but extreme care should be taken during servicing so the disc stays in the needed range. When the disc surface is very meaning, curved or if someone mentions problems with rough brakes or pedal vibration, refacing the disc with a wheel brake lathe or changing it with a new disc is the solution. If you want to reduce runout, use a brake lathe that fits onto the hub, as it trues the disc in place of the hub and bearing. Every disc will show the minimum thickness allowed, marked on its untouched side, showing the least amount the disc should be machined. The thickness of the disc at this point must not be machined below the recommended level. Before you install anything, check that both the brake disc face and hub adapters are clean, rust free and not contaminated. While brake lathe operation, strictly go by what the manufacturer advises and grind two sides together to avoid a slanted or rough disc cut. The TIR and thickness limits should always be maintained during refacing which means operators of disc turning equipment must pay close attention to their work.