An adjuster for an air disc brake, the adjuster comprising an input shaft for engaging with a brake lever drive pin, and an output for transmitting rotation to one or more brake pistons, the adjuster further including: a one-way clutch arrangement for transmitting rotation in one direction from the input shaft to the output, but preventing transmission of rotation from the input shaft to the output in the other direction; and an over-torque clutch arrangement for transmitting rotation from the input shaft to the output shaft at low torques, but preventing transmission of rotation from the input shaft to the output shaft above a predetermined torque threshold, in which the over-torque clutch arrangement includes a clutch plate and a ball-carrying plate, a plurality of ball bearings, and a spring arrangement for forcing the ball bearings axially against the clutch plate, the clutch plate including detents for seating the ball bearings and preventing rotational movement of the ball bearings relative to the clutch plate as long as axial movement of the ball bearings relative to the clutch plate is prevented by the spring force, and the detents including ramps for allowing the ball bearings to move rotationally relative to the clutch plate when the axial force of the spring arrangement is overcome, and the ball-carrying plate including pockets for retaining the balls in position relative to the ball-carrying plate as the balls move rotationally relative to the clutch plate, in which one of the clutch plate and the ball-carrying plate provides an input to the overtorque clutch arrangement and the other of the clutch plate and the ball-carrying plate provides an output of the overtorque clutch arrangement, characterised in that the pockets in the ball-carrying plate are in the form of through holes through the ball-carrying plate, a base for the through holes is provided by a thrust washer disposed behind the ball carrying plate, and in which the spring arrangement is arranged to bias the thrust washer towards the ball-carrying plate. a one-way clutch arrangement for transmitting rotation in one direction from the input shaft to the output, but preventing transmission of rotation from the input shaft to the output in the other direction; and an over-torque clutch arrangement for transmitting rotation from the input shaft to the output shaft at low torques, but preventing transmission of rotation from the input shaft to the output shaft above a predetermined torque threshold, in which the over-torque clutch arrangement includes a clutch plate and a ball-carrying plate, a plurality of ball bearings, and a spring arrangement for forcing the ball bearings axially against the clutch plate, the clutch plate including detents for seating the ball bearings and preventing rotational movement of the ball bearings relative to the clutch plate as long as axial movement of the ball bearings relative to the clutch plate is prevented by the spring force, and the detents including ramps for allowing the ball bearings to move rotationally relative to the clutch plate when the axial force of the spring arrangement is overcome, and the ball-carrying plate including pockets for retaining the balls in position relative to the ball-carrying plate as the balls move rotationally relative to the clutch plate, in which one of the clutch plate and the ball-carrying plate provides an input to the overtorque clutch arrangement and the other of the clutch plate and the ball-carrying plate provides an output of the overtorque clutch arrangement, characterised in that the pockets in the ball-carrying plate are in the form of through holes through the ball-carrying plate, a base for the through holes is provided by a thrust washer disposed behind the ball carrying plate, and in which the spring arrangement is arranged to bias the thrust washer towards the ball-carrying plate.