A vehicle washing system includes a frame disposed above a vehicle treatment area, and an extendable and retractable scissor mechanism coupled to the frame. A rotatable top brush is coupled to a bottom end of the scissor mechanism, and the scissor mechanism is extendable downward to lower the top brush into engagement with a vehicle body and retractable upward to remove the brush from engagement with the vehicle body. The scissor mechanism may include a brush support flange coupled to a bottom end of the scissor mechanism. An anti-spin member may extend from the support member to the scissor mechanism to prevent bending of the scissor mechanism in response to rotating to the top brush. The anti-spin member may be in the form of a fork that slidably engages a protrusion of the scissor mechanism.