Abstract: Conventional fluid control circuits for brakes, including separate parking and retarding valves, include high volume lines and/or complex mechanical linkages to selectively effect the braking functions. This invention provides a relatively non-complex fluid control circuit (10) for closely controlling engagement of brakes (15), including a first valve (25) for controlling engagement of the brakes (15), a pilot line (20), a second valve (47) connected to the pilot line (20), and movable between a closed position and an open position for venting an inlet (28) to the first valve (25), and a third valve (19 or 22) for closing the pilot line (20) and the second valve (47) or for venting the pilot line (20) to open the second valve (47) to vent the inlet (28) to the first valve (25). The third valve (19 or 22) may include interassociated parking (19) and retarder (22) valves adapted for common attachment within a cab of a vehicle for ready access by an operator thereof.