Brake grease is essential for quiet, free-moving brakes - but only in the right places and the right type. The wrong grease or the wrong spot causes problems. Here is which brake grease to use where.
Guide pins: high-temp synthetic
The caliper guide (slide) pins need a high-temperature synthetic grease that will not wash out or harden, so the caliper slides freely; see caliper slide pins. A seized pin from dried grease is a top cause of a dragging caliper; see why calipers stick.
Pad contact points: brake lube
The pad ears where they slide in the bracket, and the pad backing where it touches the caliper piston and fingers, get a thin film of silicone or ceramic brake lube to stop vibration and stick-slip; see abutment clips. This quiets the brakes.
Never on the friction surface
Never put any grease on the pad friction material or the rotor face - it destroys braking and is dangerous. Keep grease strictly on the metal sliding and contact points, not where the pad meets the rotor.
Do it right
Use proper brake-rated grease (not chassis grease), a thin film in the right spots, and clean the surfaces first; see quiet noisy brakes. Pair with quality pads and fresh hardware.