Suspension. Inspect the suspension system for missing, broken, damaged, worn, rusted, or modified wheel bearings, springs, or frame that would affect vehicle stability. Wheel Bearings. Wheel bearings out of adjustment can cause wander, unequal brake action, and noise due to interference of parts. Springs. Air Suspension. Some trailers and semitrailers may be equipped with air suspension systems. Inspection of the system consists of checking for air leaks, proper height, and ride level. CAUTION: The inspector should not use a creeper under the vehicle unless the vehicle is properly jacked and supported. Shock Absorbers (if equipped). Alignment. Inspect axles for broken, damaged, worn, rusted, bent, or modified axle beams, spindles, or mountings that affect wheel alignment, tracking, toe-in, caster, or camber enough to affect vehicle stability.