Abstract: A reaction type disc brake is provided with a mechanical actuator in the form of a helical thrust bearing whose nonrotatable cam component is part of or fixed relatively to the caliper. The rotatable cam component is housed in the caliper and is axially displaceable as well as rotatable therein. The rotatable cam component acts on the directly operated brake pad assembly via an axial thrust bearing and the reaction thrust is received directly by the caliper and applied to the indirectly operated brake pad assembly. The rotatable cam component is turned by means of a laterally flexible member which extends into the housing and which is placed under tension. The lateral flexibility accommodates the axial travel of the rotatable cam component. The helical thrust bearing comprises bearing needles disposed between helical cam tracks on the rotatable and nonrotatable components.