1.3 Most Common and Preventable Failures | ATRO Engineered Systems, Inc.

1.3 Most Common and Preventable Failures

1.3 Most Common and Preventable Failures


  • Never re-use U-bolts!
  • Check they are the proper grade
  • Ensure proper alignment (check condition of top plate and saddle alignment holes)
  • Allow suspension to settle, re-torque while under load.
  • Torque U-bolts per specifications – re-torque at 500 miles and check periodically


  • Proper U-bolt maintenance will increase spring life but springs will fatigue and wear
  • Cracks are the primary sign of fatigue
  • One overlooked factor in spring longevity is brake balance; a poorly adjusted brake makes the other brakes overcompensate and the spring at those axle ends will get “wound up” more than if all brakes are pulling equally

Torque Rod Neglect

  • Affects spring life, bushings, brackets, bolsters, shocks, air bags and other suspension hardware
  • Check for failure periodically – especially transverse rods

Lubrication Failures

  • Inhibits normal free movement, resulting in part breakage
  • Wear is accelerated; wear patterns are exaggerated

Bushing Failures

  • Waiting to replace worn bushings until after they’ve created a secondary, more expensive problem

Shock Absorber Neglect

  • Affects spring life, bushings and other suspension hardware causes additional strain and vibration on radiators, electrical systems, cabs and tires, defective shocks can also contribute to air bag failure