1.3 Most Common and Preventable Failures

U-Bolts

• 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

Springs

• 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