Abstract: A portable apparatus for aligning the axles of a tractor, a trailer, or other vehicle and for detecting bends, bows, twists amd other irregularities in vehicle frames, has a light source used to provide a reference plane from which measurements can be taken. Dual targets are attached to the underside of the vehicle frame and are used in conjunction with the light source to establish the reference plane. The light source is slidably arranged on a U-shaped frame and is positionable to project a light beam at the targets. The U-shaped frame is directly attached along the center axis of the wheel axle so that the horizontal bar on which a light support is arranged with be parallel to the wheel axle and thus provide an accurate measurement of missalignment. The U-shaped frame and dual targets are provided with features which allow both to be leveled easily. Rollers are provided on the leveling supports of the U-shaped frame to facilitate movement of the frame along the underlying surface as the axle is aligned.

Abstract: A portable apparatus for aligning the axles of a tractor, a trailer, or other vehicle and for detecting bends, bows, twists and other irregularities in vehicle frames, has a light source used to provide a reference plane from which measurements can be taken. Dual targets are attached to the underside of the vehicle frame and are used in conjunction with the light source to establish the reference plane. In certain embodiments, the light source is slidably arranged on a U-shaped frame and is positionable to project a light beam at the targets. Once a reference plane is established, a gauge can be used to measure irregularities in the vehicle frame by measuring the distance from the reference plane to the underside of the vehicle frame. The U-shaped frame is directly attached along the center axis of the wheel axle so that the horizontal bar on which a light support is arranged will be exactly parallel to the wheel axle and thus provide a more accurate measurement of misalignment.