Abstract: Mobile service apparatus for movement from a first location to a second location includes a frame. The frame includes a floor upon which a vehicle to be serviced can be moved with the frame having a forward end, a rearward end, and spaced sides extending between the ends. A roof is provided supported by the frame and overlying the floor, and the apparatus has at least one corner post assembly positioned adjacent one end of the frame and adjacent one side of the frame for maintaining the roof space above the floor. The corner post assembly includes a generally horizontally extending upper arm movably held by the roof, a generally horizontally extending lower arm movably held by the frame and underlying the upper arm, and a spacer joining the upper and lower arms.