A co-axial wear adjuster and wear sensor for a brake caliper includes a sleeve having an external tooth form engageable with a toothed adjustment wheel of a brake tappet. The sleeve rotates with the tappet and is threaded to engage a relatively non-rotatable, but axially movable, bolt. A wear sensor is partly within the sleeve and has a plunger operably engaged with the bolt. The bolt may be tubular to carry a screw-threaded head whereby a position of the plunger may be set.