Certain buses equipped with Hendrickson rear air suspension. Inadequate tightening of the 5/8" bolts on the rear air suspension hanger bolts and on rear axle torque arm axle seat studs. Insufficient tightening permits movement between the components that could result in bolts and studs breaking, increasing the risk of a crash. Correction: dealers will replace the 5/8" grade 8-hanger bolts. In addition, axle spring seat fasteners will be checked for proper tightness and, if needed, tightened to specifications.