A wear adjustor is provided for adjusting the wear of brake pads and the brake disc of a pneumatically operated disc brake having a brake application device that can be actuated via a rotary lever. On a dispensing end of the nozzle a break-off cap is integrally formed thereon and closes off the dispensing end of the nozzle. A rotating member is in the housing. The retainer includes a base portion with a front surface and a back surface. In order to reduce the fabrication costs of the fuel pump, the invention provides that a support member that is separate from the piston is provided, which said support member is interconnected with the end region of the piston closest to the eccentric shaft or camshaft, and against which the prestressing element bears.